If you were paying attention to the 2010 NY Governors race, or just to the thousands of jokes it spawned you know the phrase “The rent is too damn high!” What you might not understand is what vacancy rates are and how keeping them low ensures that rents will stay high. In this post I will use the words of landlords themselves to help regular people understand this so we can push for a world of housing abundance and affordable rents.

What Is A Vacancy Rate?

First off we need to understand what a vacancy rate is. Simply put, it’s the % of units that are unrented over a period of time. It is usually calculated across a whole year, so if a home was vacant for 36 days out of 365 it would have a vacancy rate of around 10%. Now calculating a vacancy rate for an individual home isn’t very useful. Instead we want to calculate it for a whole building, a neighborhood, or even a whole city.

Moving Takes Time

One common misunderstanding about vacancy rate, is that a home which is being cleaned out or renovated between renters is considered vacant. This is why pretty much no city has a 0% vacancy rate, because someone is always moving out somewhere. It almost always takes a few days or even weeks after a move out for a home to be cleaned up and rented again.

There is a chance that a new renter would sign a lease that starts the literal day after the last lease ended, but that’s unlikely because they’d be paying for an apartment that wasn’t even cleaned. If you see that happening it is a clear sign that there aren’t enough apartments available in that area and renters are willing to either accept a dirty apartment, or lose out a day or two of living there to ensure that they get a place.

Who Benefits From Low Vacancy Rates?

So now that we understand what a vacancy rate is, we must ask ourselves, who benefits from keeping vacancy rates low? The main beneficiaries of a low vacancy rate are landlords. Don’t take my word for that though, let’s listen to a landlord explain it himself.

If you don’t want to watch the whole video here are a few key quotes.

“If a vacancy rate is zero in a particular town or a particular building, then that probably means the landlord set the rent too low... Time to increase the rent.”

“The properties that I buy, I try to keep them at about a 4% to 5% vacancy rate. So that means when we have a tenant leave the property, a few short weeks after paint and carpet, we have a tenant moving right back into that property.”

“Another thing that I look for is over building. I personally like to invest in areas where there's almost no building going on.”

But We Built Stuff And The Rent Is Still High!

This is a common complaint that is trotted out to prevent additional building. Vacancy rate does a good job of answering it though. If new homes are built, and those homes are quickly filled, then the vacancy rate stays low and the rents stay high. The answer there is to not stop building, but actually to build even more such that the vacancy rate actually rises.

What If We Overbuild?

Okay, so you’ve heard me call for more building, but there must be some limit right? Homes take months, or even years to construct, so what happens if we finally build enough housing to drop vacancy rates and rents and there are still thousands more units under construction? Well we don’t have to guess about that, because it is happening right now in multiple cities in America, like Las Vegas and Austin. Don’t take my word for it though, here’s another landlord straight up telling you that increasing housing supply results in higher vacancy rates which leads to lower rents.

How Vacancy Rates Affect Home Prices

We’ve finally gotten to the real reason many people oppose lowering vacancy rates, they fear it will drop their own home prices. The landlord in the above video certainly thinks this is the case. He notes

The history of the U.S housing market says that when rents go down home prices go down and the mechanism that's going to cause the price is going to go down is landlords selling because right now lots of them are losing money with their cost of debt.

Who Loses Here?

Think of all the articles you’ve seen about AirBNB landlords raising housing prices/rents because they’re taking homes off the market, or companies like Blackrock buying up large numbers of homes and raising rents. What we’re seeing in Vegas is those landlords being forced to sell those exact homes (potentially at a loss) because the vacancy rate raised and the rents they could charge dropped below their costs to maintain those properties.

It’s also possible that the large developers who are in the process of building thousands more homes in these cities will lose out. They may finish their projects only to find that they sell for less than the cost to build. In the worst case scenario these builders will realize this part way through construction and abandon a half completed structure. This can cause real issues, but good blight ordinances can allow municipalities to seize this land either demolish the unfinished structure, or better yet, complete it into something useful.

What About Homeowners?

Big developers aren’t the only ones who own homes though. There are also millions of regular people who own homes in America. What happens to them if home prices drop? Well it certainly isn’t going to feel good if the home that you had thought was worth $500k is actually only worth $350k. This creates a situation where moving or taking out more debt both become much harder because mortgages are underwater. This happened to millions of people, including me, during the great recession and it certainly wasn’t fun, but there are currently millions of people who are drowning due to high housing costs right now. Which is worse?

Hidden Benefits Of Housing Abundance For Homeowners

Building more homes to create higher vacancy rates and lower home prices does produce some benefits to existing homeowners as well though. First off, if a home’s assessment drops then the amount it’s charged in property tax will also drop. Now, your town may delay assessing or raise property tax rates to prevent this, but that is really a function of how good your elected leaders are and how much your municipality has to spend. If the new homes in your community were built in an area that already has infrastructure like roads and pipes then the extra cost to the town’s budget for those homes is minimal. They’ll actually provide a surplus of value to the community and allow lower property taxes, increased municipal services or both. This is covered well in this Not Just Bikes video based on Strong Towns’ work.

A Way Out For Homeowners Who Overpaid

Loosening zoning also gives homeowners who may have overpaid for their homes a way out. If your town just made it legal to build 12 homes on a plot of land that had previously only allowed one home then developers are going to want to buy that plot of land and build 11 more homes on it. Competition between developers here will lead to a period where existing home prices go up even higher, because the demand for homes hasn’t been met and there is a huge demand to build more.

Allowing 12 homes to be built where 1 once stood means that even if a developer might overpay $600k for what had been a $500k home. That’s because the cost for land for each of the 12 new homes they’ll build on that land is just $50k so the extra cost isn’t much per new home.

A homeowner who paid too much for their home could likely sell it for a profit during this time. Eventually though, enough homes will be built and home prices will drop back to lower levels. This affordability is a good thing in the long run though, and the homeowners who stay and continue to live there will benefit from others being able to afford to live in their communities too, like the teachers at their kids schools, the drivers of their buses and the people who take our their trash.

A Final Note on Quality

The fastest way to increase the vacancy rate is to build a bunch of cheaply made, low quality homes on already vacant land. I think this is a mistake too though, because these homes will quickly become trash and require either extensive remodeling or even demolition. These buildings will still claim to be “luxury” but anyone living there will show you how that isn’t the case.

@donnyskipper1Luxury” apartments in a nutshell: Part 1 👍 FoIIow my journey of EXPOSlNG my corporate landlord! #luxuryapartments #corporatelandlord #badlandlord #fyp

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This also goes for the location of the housing. We need to build homes near where people actually want to live, which is largely influenced by jobs, family, and weather. Attempting to increase the vacancy rate in a city by building far off, low quality sprawl housing just leads to abandoned suburbs that can’t support the cost of the roads and pipes they require. These can and do become abandoned and stop contributing to the housing supply after a few years. We would do well to update our code to require higher quality homes, with better insulation, air sealing and noise blocking, and to keep using zoning to prevent far flung farms and forests from being turned into suburban sprawl.

Conclusion

Let’s use our laws to not just allow, but actually encourage quality homes in desirable places. This is a key step to making homes more affordable, but it’s more than that. Denser homes are inherently more energy efficient than detached homes because they have fewer exterior walls. This also means that they require fewer materials to build and convert less farmland and wild land into housing. We should all work together to encourage sustainable housing like this to increase vacancy rates and improve affordability so everyone can profit greenly!

P.S. If you got this far and want to learn more about dense, sustainable housing, check out this great video by Climate Town.

Apartments Save Land

The most obvious benefit of apartment buildings is that they can house far more people than single family houses on the same land area. People sometimes look at densely built cities like New York or Paris and see concrete jungles, divorced from nature. But, what if all the people of those cities were living in traditional homes on quarter acre lots? Lets do some math on that. Manhattan is 14,000 acres with 1.6 milllion residents. In the US the average household size is 2.5 so we’d need 640,000 detached homes for all of these people. Put these on quarter acre lots and you’re talking 160,000 acres, and that’s not including the space for streets, stores, parks, etc.! The residents of Manhattan are likely saving well over 150,000 acres of land just by living more densely. By not using this land for housing we can do other things with it like farming, solar and wind production, heck we could even just let it be wild.

The environmental costs of sprawling like this are real. I just have to look a mile from where I live in State College to see an example. The Yards of State College was built on 44 acres of land that used to be a mix of farmland and wild areas. There was a lot of protest when it was constructed because they were building on top of a source of our drinking water, but it got built anyways. It provides housing for 1,000 people, which is great, but it uses a lot of land to do so and puts its residents so far from campus that many are likely to drive (just look at how much land has been paved for parking). A single 12 story building going up downtown now will house nearly 500 people on around 10,000 square feet of land. The Yards residents could fit into 2 such buildings on less than an acre of land, but sadly our borough council just effectively banned such developments. That means that sprawl like The Yards which replaces farmland and wild areas with asphalt and buildings will continue (like this new development by our airport). This sort of development may include a bit of green grass but it is not green in an environmental sense because it destroys farms and wild lands and increases commuting distances.

The single family neighborhood that I live in is even worse than The Yards in terms of land use. It uses about 200 acres to house under 1,000 people in under 500 homes. We do have a senior living facility that houses another 300 some people, but still we’re far from dense. This is largely because State College’s zoning outlaws density here. Each home is legally required to be on at least 10,000 square feet (sqft) of land by our zoning (.23 acres). You are allowed to build duplexes (aka Two-family dwelling) here, but they require 20,000 sqft of land so there are no land savings which amounts to a de facto ban. Changing this law to simply allow denser building if people want to do so is the heart of YIMBYism to me.

Apartments Save Money

The big misconception about dense building is that apartments/condos cost more than detached homes. An apartment may require some things a home doesn’t, like an elevator, but it also massively cuts other costs, like land. My town has very few buildable lots left, so you’ll be paying $150,000-$250,000 just for land to build a home. The land alone for 6 detached homes here would cost over a million dollars, and in reality there aren’t even 6 vacant lots left here. A 6 story apartment building on 1 lot here would save at least $750,000 in land costs. That $750,000 could easily fund a nice elevator and other additional costs of building taller with money to spare.

The issue again is zoning, with Floor Area Ratio (FAR) limiting the square footage of a building as a multiple of the area of the lot it’s built upon. This means that as a building becomes taller it must legally become narrower as well. That rule, along with other rules (like parking minimums) adds a lot to the price of a building. Loosening or eliminating these requirements is another YIMBY goal. If people want to live without a car they should be allowed to buy a unit without the added cost of parking. If they don’t want a yard they should be allowed to buy a home without one. The more people we can put in a small area downtown the less area we waste building sprawl housing and the less fuel we waste commuting to that. It’s that simple.

Density Helps Towns

Density is also key to making a town a great place to live. A frequent complaint I hear about State College is that our restaurant scene is weak. This is largely due to our zoning laws preventing dense building and limiting where restaurants can be built. Before moving here I used to live in Ithaca. Its downtown has buildings on far smaller lots (my house was on a 0.04 acre lot), along with many apartment buidlings. This dense building provides a customer base that could support many good restaurants, coffee shops, etc. These businesses are built right into the neighborhoods too, so people can actually walk there from their houses. My own house there was about 300 feet from a sports bar and it was great to be able to just walk over to watch a game and have a beer or two. In State College we limit the places such bars can be built and require that they have huge, expensive parking lots, then wonder why we have a weak restaurant scene and a serious drunk driving problem.

Beyond allowing a better restaurant scene and saving on construction costs, dense building also saves towns money. The miles of local streets used to connect homes are paid for by property taxes. Most people are blissfully unaware of how much roads cost to build and maintain, but once you see the numbers you can’t ignore what a huge cost they are. State College budgeted $19 Million for Capital Improvement projects in 2022 and well over half of that was earmarked for roads and parking. Sewer costs are another big ticket item, and though dense building requires bigger, more expensive pipes, it requires far fewer miles of them resulting in a lower total cost.

The Not Just Bikes Youtube channel partnered with the Strong Towns non profit to do a great job of explaining how dense development saves cities money check out their whole video series if you’re still confused. The short version is that denser homes require fewer miles of roads and pipes, and so they require government spending to maintain. The money for these projects comes out of residents pockets in the form of property tax, so anyone who cares about saving money should care strongly about this. Even if you don’t personally live in a condo, having them in your town adds to the tax base while only marginally increasing government spending. That results in lower property tax, and/or better government services for all residents.

But all new apartments are luxury!

Another argument against new building is the claim that new units will all be luxury units and drive up prices. This makes some sense in that new developments are often marketed as being luxury, but what does that really mean? Generally it’s just higher end appliances, and potentially amenities like gyms or pools. When you look at the total cost to build a new apartment it becomes clear that the extra cost of these things is just a small fraction of the cost of a whole building. If making a unit “luxury” only adds 10% to its total cost, but lets a developer sell the unit for 50% more then they’d be fools not to build it. That will continue to be true until the market for “luxury” housing is saturated and people aren’t willing to spend so much more to buy/rent them.

America has built so little housing over the last few decades that the pent up demand is so huge that we literally have to build millions more homes before we see truly affordable homes get built naturally by the market, and even that is dependent on low enough material/labor costs. Until the demand for luxury units is met the main way to ensure that “affordable” units are also built is with laws that require X% of new units in a building be affordable.

State College originally tried this with the luxury student housing it was building, but it quickly found that adults with families didn’t want to live in a building full of college students, even if the rent was low. The next option they tried was called fee in lieu. This allowed developers to pay a fee that the borough would use to build/improve low income housing rather than building new units directly. I recently saw an example of this in action near my house when I noticed that a dumpy old motel nearby had been converted to affordable apartments with efficient heat pumps added to all the units. It turns out that this upgrade was done with the help of the fee-in-lieu funds the borough had collected.

More affordable housing is greatly needed in State College and other popular cities in the US, but our regulations must walk a tightrope. If we require too high a fee-in-lieu or percentage of affordable apartments then new developments will become unprofitable and builders simply won’t build them. We often see anti-development NIMBY’s pretend to care about affordable housing by advocating for all new buildings be 100% affordable homes. This is a front because these NIMBYs know that 100% of 0 new buildings is still 0. These same people will scream that their neighborhood doesn’t need affordable housing, or will actively be destroyed by its existence if a developer actually tries to build some there.

Supply and demand is real

The other reality with luxury units is the law of supply and demand. Landlords and realtors look at the balance of supply and demand in an area by calculating its vacancy rate. This is what percent of homes in the area are currently vacant. As long as vacancy rates are low rents will continue to rise. There are studies that show this, but you can also just look at landlord forum posts to see how rent price is tied to vacancy rates. There are 2 ways to increase vacancy rates, either have fewer people or build more homes.

In high demand areas like my town, we are not seeing population drop. Well, if you look at our recent census results we did, but those in the know will tell you that this is the result of poor census taking methodology. This may have been deliberately done to reduce our electoral power, but that’s a topic for another blog. We have built thousands more units downtown in the past few yearsand these new units are almost all rented out, but they’re not increasing our population or decreasing our vacancy rates much because their renters are often college kids who would have been crammed 2-4 kids into a single room in the past. These students (or their parents) are willing to pay over $2,000/month for a single room. That is a LOT of money and until we build enough housing to fit everyone willing to pay so much all new development here will likely be focused on meeting their needs because it’s so profitable. Who would build an apartment to rent for even $1,000/month when there is a waitlist of students ready to pay $2,000/month? Pretending this demand is not here does nothing to fix our housing issues.

Why State College Bans Dense Housing

My local government has kept the demand for student housing from totally inflating the price of single family homes here by legally limiting which homes can be rented to students. Go to any gov event where student housing is discussed here and you’ll hear a lot of anti-student sentiment. Some arcane state law prevents this limitation on multi-family homes which likely explains why my local gov has banned construction of multi-family homes on most of our land. That doesn’t mean it’s a good choice though.

My town is named State College because Penn State is the reason for its existence. PSU is the economic engine of our town and we benefit by allowing housing for students to be built right next to it. The alternative to this is that apartments are built further away and students commute in by car or bus. It is true that the university could be building dorms on their own land, but residents should remember that PSU is tax exempt and such buildings would add costs to our community without adding revenue. That is how many college towns find themselves in dire financial straights despite the presence of a wealthy university in them. Until we end tax exemption of universities, college towns are better off having buildings built by taxable entities than by the schools themselves.

My YIMBY Dream for State College

State College is currently the 13th most populous city in Pennsylvania. We could easily be in the top 10 and the top 5 is possible. Most of these potential new residents already drive here daily for work and we’re budgeting millions to provide roads and parking to enable this. Instead we simply have to build enough housing for them to find an affordable place to live here, reducing traffic and improving borough finances. We don’t have to force everyone to do live in an apartment here, but we should at least make it legal to build enough housing for those who want it and to build it all throughout the borough and not just in a tiny sliver of land by PSU.

The best solution I can see for State College is to allow super dense housing for students on land that pays property tax to the borough, land that is directly adjacent to the university. Allow enough of this to be built to meet all of the demand for $1,000+/month rental units so other buyers/renters can compete for new builds. Along with this we should update our zoning code to require even greater energy efficiency, durability and sound proofing so the new buildings will be assets to the town for decades to come and not liabilities. We should also update zoning to allow even more dense housing beyond just student housing so the many employees of the university and the borough can actually live here and not 30+ miles away. Our zoning should also not require huge amounts of parking for each apartment so people who choose to live without cars don’t have to pay for those who do. We should create a vibrant food scene by allowing coffee shops and restaurants to open up right in our neighborhoods and get most of their business from foot and bike traffic from all the dense housing that is built. Finally, use all the fee-in-lieu payments and property tax from this to fund affordable housing and improved city services like a truly safe connected bike network and electrified bus or tram service.

State College could be a truly world class town. There are plenty of rural places in PA where misanthropes can live without much interaction with other people so we should not allow them to limit our future here. State College is one of the few places where thousands more people actually want to live. We should embrace this by making it physically possible for them to do so. It’ll improve both their lives and ours and we can all profit greenly together.

Note: I originally wrote this post 5 years ago for my friend’s blog. That site is seeing a lot less use these days and loading slowly so I figured I should copy the content over here to ensure it is still accessible and open it up to new readers. I’ve made a few minor updates to bring it up to date.

Keeping Your Thermostat The Same All Day Wastes Money

No one likes to waste money, right? Unfortunately, there are still some pernicious myths out there slowly draining our bank accounts. One of these myths is that leaving your thermostat at the same temperature all day somehow saves money. This is untrue for the vast majority of homes, yet the myth won’t die. Many sites on the internet will tell you that lowering your temperature by 10 °F during the day can save you 10% on heating costs, but they don’t explain why. This lack of explanation leads people to keep believing this myth and wasting money and energy. On my Money Saving New Year’s Resolutions post a commenter wrote the following:

I’ve heard that it’s more efficient to just leave the house at a constant temperature so the heat/AC can just work at a regular level instead of working overtime to “catch-up” in the morning or when people get home from work

This pretty much sums up the common misconception about thermostats. I’ve heard similar statements from many friends and relatives and have spent hours explaining why it’s wrong. In this article I hope to explain once and for all why leaving your thermostat the same all day wastes money. (Note: I’m only going to explain this in depth for heating, but the same basic principles apply to cooling with an air conditioner as well. The main difference for AC is that an AC unit actually becomes more efficient after the sun goes down and the outside air temperature drops, so there’s even more reason to avoid running it during the heat of the day)

A Furnace is Not a Car

To understand why it makes sense to turn down your heat during the day, you have to understand a bit about how your home heating system works. Most people have limited experience with furnaces and so they start thinking about car engines because they understand those more. People understand that flooring the gas pedal is not efficient for a car’s engine and they apply this logic to their furnaces.

Car engine logic does not apply to furnaces. Car engines have to operate at many different speeds (RPMs) with different amounts of fuel flowing into them. An engine will naturally have different efficiencies across this range and you get the most out of the engine by keeping it at its most efficient combination of RPM and fuel flow by shifting gears appropriately and not slamming down on the gas pedal. Furnaces, in contrast, generally only have one speed, maybe two or three if they’re fancy (the technical term for furnace speeds is “stages”). The design for furnaces is much simpler and they’re built to be most efficient when running at full blast.

Furnaces are also much more efficient than car engines because they’re burning something to make heat. Car engines, on the other hand, are burning something to generate spinning motion in the wheels. As you might have guess it’s hard to turn a fire into spinning motion and car engines end up generating a lot of waste heat. For home furnaces this is not an issue, since generating heat is the goal. This is why most gas car engines are around 20% efficient while modern furnaces are 80-98% efficient. Older furnaces can be as low as 56% efficient, so if you own your home and have an old unit you should look into upgrading it.

How Furnaces Work

The inefficiency of modern furnaces is largely due to heat that escapes your house through the furnace exhaust. You could make a nearly 100% efficient gas furnace by simply piping the exhaust into your living space. Of course no one does this because the carbon monoxide in the exhaust would kill everyone inside. Instead, efficient gas furnaces run their exhaust through a heat exchanger that pulls heat out of the exhaust before it is vented outside.

Heat exchangers aren’t perfect. They can’t extract heat as effectively right when the furnace is starting up or shutting down. This is why changing your thermostat every minute or two or having an oversized furnace for your house wastes money. Running a furnace for a while means that a higher percentage of time is spent burning full blast when the heat exchanger is most efficient. This is why using your furnace to heat your home up from, say, 58 °F to 68 °F in a single shot is more efficient than going from 58 °F to 63 °F, pausing for a minute, then going from 63 °F to 68 °F. The furnace isn’t wasting energy working hard, it’s actually saving it.

What About Electric Heat?

So far we’ve only talked about heaters that burn fuel. This is because most U.S. homes are heated by burning fuel in a furnace (usually natural gas, but sometimes heating oil, propane, or kerosene), but a significant number use electricity to heat instead. Electric heating can be even more efficient than burning fuel. Electric resistance heating, like what you see in baseboard heaters, is around 100% efficient. This means every watt of electricity you put in produces a watt of heat. These aren’t more efficient when heating many degrees in a single run, but they aren’t less efficient either. The issue with resistance heaters is that electricity is a lot more expensive per watt than something like natural gas right now. So, while resistance heaters are technically more efficient, they can cost a lot more to operate. If the resistance heater is powered by a natural gas generator that is only 50% efficient then its net efficiency is worse than burning that gas directly in your home for heat, but if its powered by a renewable source like hydro or wind it is better.

Electric heat pumps are even more efficient than resistance heating. They work by stealing heat from the outdoors and putting it into your home. Because they don’t have to create all the heat that they’re putting in your house, they can actually be more than 100% efficient. For example, they can can pull four watts of heat into your home from the outdoors using just a single watt of electricity. This is incredibly amazing when you think about it. A 400% efficient heat pump powed by a 50% efficent natural gas generator puts more heat in your home than a 95% efficient gas furnace was burning 2 times as much gas (see this video for thorough details)! Heat pumps are even more amazing because they can cool your house as well as heat it, so you don’t need an air conditioner and a furnace, just a single heat pump.

The main problem with heat pumps is that units installed on homes often can’t pull in heat super fast. Heating a house from 55 °F to 70 °F with a heat pump might take over an hour instead of a few minutes. Lots of people can’t handle waiting an hour, so many heat pump installations include backup resistance heating strips to heat things up quickly when needed. If you have a heat pump with a backup resistance unit, you will be more efficient by using the resistance part less. The heat pump is two to four times more efficient than the resistance heat strips, depending on outdoor air temperature, so you basically want to avoid using the heat strips as much as possible.

A smart programmable thermostat, like a Nest, can help avoid using resistance heat by turning your heat pump on in advance. This way your house will be at the temperature you want by the time you want it there. Without this type of thermostat, you could still just toughen up and live through your house heating a bit slowly. But you might be weak and end up turning on the backup resistance heating unit to warm your home faster.

Overuse of backup resistance heat strips in a house that has a heat pump is basically the only case where leaving your heat at the same setting all day might be more efficient. For example, if your heat pump is able to maintain your home at 68 °F, but you would turn on the resistance heat to push it from 55 °F to 68 °F, then you might not want to turn it down to 55 °F during the day. The outdoor air temperature during the day will also usually be warmer than it is at night so running the heat pump then will be slightly more efficient. Even this case isn’t a slam dunk, though, because your house loses soooo much more heat when it is warmer and lost heat is lost money.

How Heat Gets Out of Your House

Okay, so now you get how running most heaters for longer periods of time saves energy and money. This alone is just a small part of why turning your thermostat down for some of the day is super efficient. The heat escaping from your house is responsible for most of the money wasted by leaving a thermostat at one setting all day.

Basic physics explains how heat transfers faster when there is a greater difference in temperature between two systems. That means that when your house is 70 °F it is transferring heat to the world outside faster than when it is only 60 °F. Exactly how fast depends on how big your house is and how well insulated it is. Larger houses have more surface area to transfer out energy so they lose heat faster.  Well insulated houses have a better barrier that helps trap heat inside. Your furnace has to generate heat to replace every watt of energy that is transferred out of your house. So, the more heat you lose the more your furnace runs and the more your furnace runs the less money you have.

Your House is Like a Cup of Coffee

Don’t worry if you’re not all the way on board yet; heat transfer can be hard for people to wrap their heads around. Try thinking of your morning cup of coffee. It comes out really, really hot but quickly cools to a drinkable temperature. This quick initial cooling is because there is a big temperature difference between the coffee and the air, so the air takes heat from the coffee faster. Similarly, if you keep your house hotter then the outside air takes heat from it faster.

If a cup of coffee has been sitting around for a while it will still be a little warm and it will take a really long time for it to cool down to the actual temperature of the room. This is because the air takes heat from the coffee more slowly as the coffee gets closer in temperature to the air. Similarly keeping your house cooler in winter means that the outside air will take heat from it more slowly.

How quickly the coffee cools also depends on how well insulated a cup it is in. If you put coffee in a thin paper cup it will cool more quickly than if you put it in a styrofoam cup because styrofoam is a better insulator. Scientists can calculate just how well a material insulates and they call this the R-value of that material. When you buy insulation for your house the R-value will be prominently advertised. Adding insulation is a great home improvement project that can save you hundreds of dollars a year. I added R-60 insulation to the attic of my old house in Ithaca over a weekend for less than $400. It was a couple days of hard work, but it saved me tons of money over time and helped my house sell when it was time for me to move. This is like putting a nice thick lid over the coffee cup that is your house; it’ll keep it warmer far longer. If you insulate don’t forget to air seal as well because air moving through cracks and holes in your ceiling will transfer heat right through your insulation. Using caulk or spray foam to seal the holes in your ceiling can massively reduce this major source of heat loss.

Coffee Schmoffee, I Demand Math!!!

Okay, I can hear some of you screaming that a simple coffee analogy isn’t good enough! Yes, you won’t be satisfied until you see some real equations (if that isn’t you, feel free to skip to the next section). Let’s do some simple math to see how this works. Imagine you have a 1,000 square foot house that has 10 foot ceilings. It’s basically a 50 foot by 20 foot by 10 foot box. The walls have an R-value of 10, the floor has an R-value of 20 and the ceiling has an R-value of 25. Let’s imagine that the outside air temperature is 40 °F and the ground temperature is 50 °F. How much more energy does your house lose every hour when your thermostat is set at 70 °F instead of 60 °F?

The Heat Transfer Equation

BTUs of Heat Transferred per Hour = Surface Area in Square Feet × Temperature Difference in Farenheit / R-value

As you can see, our fantasy house loses an extra 6,400 – 4,100 = 2,300 BTUs of heat every hour when its thermostat is set to 70 °F instead of 60 °F. If you turn your thermostat down to 60 °F when you leave to go do stuff during the day and turn it back up to 70 °F when you get back eight hours later, you save 8 × 2,300 = 18,400 BTUs per day. Setting the thermostat back again during the eight hours you’re asleep doubles this to 36,400 BTUs per day. If you did this every day for a whole month you would save over 1 million BTUs!!!

Real houses are certainly more complicated than our fantasy house. For one, they’re likely much larger with the average American house being more than double the size of our fantasy home, and thus losing a lot more heat. They are also probably not perfect cubes, but instead have additions that jut off in different directions, increasing the surface area they lose heat from. The heat inside them also isn’t evenly distributed. Since hot air rises, the air touching the ceiling will be a few degrees warmer than air on the floor. This is why the most important place to insulate your house is your attic (this is true for AC as well, but for a different reason).

It’s not all bad news, though. Many Americans live in townhouses and apartments that share walls with other living spaces. Because the temperature on the other side of a shared wall is close to that of your own home, you likely don’t lose much heat through it. If you keep your heat significantly colder than your neighbors’, your home will actually gain heat through shared walls based on the same principles of heat transfer explained above.

Understanding the heat transfer equation also helps you understand how important each degree you drop your home temperature is. In the above example, dropping it by 10 °F while the house is unoccupied saved 2,300 BTUs per hour. Dropping it by 20 °F (all the way down to 50 °F) would have saved twice as much (4,600 BTUs per hour). Dropping a thermostat down to 50°F may risk pipe freezing if it’s very cold outside and a house has poor insulation. It should be okay in most houses though and 55 °F should be fine for pretty much everyone. Here’s an online heat transfer calculator if you want to explore this more for your own house.

How Does This Hit My Bank Account?

Now you understand that leaving your thermostat set high all the time causes a bunch of BTUs of heat to flow from your house to the outside world, but maybe you’re still wondering how exactly this affects your bank account. Well, your furnace has to burn extra fuel to replace every BTU of energy that flows out of your house, so you end up paying for those lost BTUs. If you have a furnace that costs a lot to operate, like resistance baseboards or an old gas furnace, then this can cost a lot. Having a bigger house and worse insulation make wasting heat cost even more. Setting your thermostat from 70 °F down to 55 °F during the day when you’re at work and down to 60 °F while you’re asleep will save a ton of dough. For example, if you lived in that huge house from Home Alone with the rickety old furnace, you could probably save well over $200 each month and over $1,000 a year! Even a small apartment can easily save $20/month by simply turning the thermostat down when no one is home or awake.

If you have a super efficient heat pump like me, then you won’t save as much money by turning down your thermostat during the day, but you’ll still likely save. This is even more true for cooling in the summer time because the efficiency of an AC increases at night when the outdoor air is cooler. My HVAC costs only around $350/year to power, but it’s still a good idea to turn it down a bit when I won’t notice a difference.

Seriously though, why are you heating your house when you’re not able to appreciate it anyways? Your dishes will not shatter if they get below 70 °F. Your pets evolved to live through the rigors of winter, and unless they’re cold blooded or some tropical bird they will be just fine at 55 °F. When you’re asleep under your blankets you won’t notice that the temperature has dropped a bit. If you have a programmable thermostat, now is the time to figure it out (if you need help, please drop a note in the comments). If you don’t have a programmable thermostat, then just make it a point to remember to turn your thermostat down every time you leave the house. Tell your friends! Tell your family! If all of us start turning down our thermostats when we’re not able to enjoy the heat, we’ll save a ton of money and a ton of energy too.

UPDATED Feb 2024 with updated links, prices and new info on ski helmets, and bar mitts

It's that time of the year when temps start dropping and lots of people start thinking that they can't bike any more. As an utter wimp when it comes to the cold I used to be one of them. My body can easily handle 100 degree heat, but at 60 F I'm shivering. Luckily, I learned how to pick out clothes to make cold weather biking really comfortable, even for a heat loving guy like me. Read on to learn how you too can bike comfortably, no matter how cold it gets.

What to wear

Most posts you find online about cold weather biking gear are all about pricey stuff for bike racing. That's all well and good for some people, but I primarily use my bike for taking my kids to school, going to the store, riding to work, etc. My cold weather biking clothes are ones that are equally at home both on and off a bike, and they're generally cheaper than cycling specific gear. Here I'll lay out the basics, explain their costs, and how you can mix and match them to ride comfortably even as the weather warms up.

One other note, every body is different. Some people are comfortable at far colder temps than I am (like this guy biking with rolled up pants in 30 F). You can drop my temperature recommendations down a few degrees if your body does better in the cold than mine. Just don't be one of those dudes that stubbornly wears shorts all winter long but refuses to bike then cause it's too cold.

Costs

Costs:
Ski Goggles: $30
Helmet Cover: $8
Half Mask: $11
Hat: $22
Jacket: $150
Thermal: $20
Gloves: $50
Flannel/Fleece Lined Pants: $42
Socks: $15
Shoes: $75
Total: $423

In the image above you can see what I wore biking on a cold 18 F day a few years ago (11 F with wind chill). The total cost of all that gear was $423. That may seem pricey but most of that stuff has already lasted 10 years or more. That means cold weather bike clothes can cost under $50/year. Much of it has now reached end of life, but some of the replacements I’ve found for it are even cheaper!

The bigger value comes from the fact that these clothes aren't just for biking. Outside of the helmet cover and the ski goggles I wear all this stuff just walking outside on any normal cold day. This sort of clothing isn't a bike specific investment, it's the stuff that anyone living in a cold environment should own. Living a climate controlled car centered life causes many of us to forget how to handle the elements, but we don’t have to disconnect from nature like this. One of the great positives from biking is ensuring that you'll spend more time out in the real world learning how your amazing body can truly deal with it.

Jackets

The first, and most critical thing you need to ride in the cold is a good coat. My go to for this over the past decade as been a 3 layer Gore-Tex jacket. It's great material, long sleeves, and hem that overlaps with my pants when I'm bent forward biking block wind great. This is critical on a bike when you can easily be going 20 MPH and thus creating your own 20 MPH wind. There's also a great pocket in the chest that I can store my phone in which I love. I didn't realize how amazing this jacket was until it lost its waterproofing and I had to buy a new one (I tried to refresh it with Nikwax, but sadly it still leaks, still great on dry days though).

Cabelas no longer makes my old coat, so I had to shop around. I settled on a REI Rainer rain jacket on sale for $70 as a replacement. I was originally disappointed that this 2.5 layer jacket held less heat than my old 3 layer one but I've made it comfortable in freezing temps by adding a cheap puffer coat under it (see below for deets). I also love how it's hood folds into the collar so it doesn't catch wind and block my rear mirror vision.

2024 UPDATE: After a few years use I can confirm that the cheap puffer+thin wind/rain jacket is all the coat you need, but that this particular REI jacket sucks. Its waterproof lining is flaking off in many places, especially around the collar and not having elastic in the cuffs means you waste time velcroing and unvelcroing them every time you want a tight sleeve fit. It’s currently on sale for $40, but I wouldn’t even pay that for it. I’m looking for a more durable 3 layer jacket that has no PFAS, elastic in the cuffs, a hood (that hopefully either detaches or stowes in the collar), and a front chest pocket to replace the old REI. Unfortunately PFAS are still in a lot of jackets and elastic cuffs aren’t so finding this has been impossible so far. I’m going to keep dealing with my bad REI jacket till this comes along though, if you find it please shoot a link my way in the comments.

Warmer Weather Jackets

The other jacket I ride with is a hi-viz yellow cycling jacket from Canari (similar to this one). This is one of the few cycling specific pieces of clothing that I own, but I've enjoyed it and its lasted well over a decade so far. The main feature I love about it is its zip off sleeves. If you get a little warm on your ride you can zip open the pits, and if you get really hot you can just remove the sleeves entirely and convert it into a vest. This was really useful back when I would commute to work on cold mornings, but then ride back in the heat of early evening. As a cycling specific jacket it also has a little pocket on the back. This feature is great when you're riding a road bike and don't want junk in the front pockets hanging low and brushing your knees. If its not raining this jacket is what I throw on between 50 and 75 F. Given how light my new 2.5 layer rain coat is though, this one is really a luxury, not a necessity.

Under the Jacket

You can layer all sorts of things under the jackets listed above to make them feel good as the temperature drops. I generally start with a t-shirt, then add a flannel shirt over this when it gets colder. I found a puffer jacket on sale from Land's End for just $33 a few years ago (the new, thicker version is currently $44). That's honestly less than the $40 I paid for a thick flannel from them and it's both lighter and warmer.

When it gets really cold I layer the flannel under the puffer, but a cheaper thermal shirt would do just as well if not better. The tan thermal shown in the picture at the top of this article is an unbranded one my dad gave me over a decade ago that I assume cost around $20. It's nothing pretty, but it gets the job done. The best thing about it for me are the extra long sleeves that truly cover my wrists. This is critical for biking below freezing, as you really don't want any gaps in the insulation around your body. To keep warm on a bike on a budget a cheap thermal like this with a puffer and a wind breaker/rain coat on top can't be beat (note for Land's end shoppers, wait for sales there, everything eventually sells for 50-70% off).

Gloves

The final thing you need to keep a jacket warm is a great pair of gloves. Without these your hands and wrists will be cold and air may flow up your sleeves and freeze you. I've used a lot of bad gloves over the years, and I thought that my fingers were just destined to always be freezing in winter. Then my wife bought me these amazing, thick, Goretex gloves from Cabela's and changed my life.

This exact model isn't made anymore, but any waterproof glove with lots of insulation and a gauntlet that goes back over your sleeves and cinches tight would do. If I had to replace them today I'd look at these $56 Gauntlet GTX gloves from REI. It's also possible that some $30 gloves off amazon would work too, just make sure they totally cover your wrists.

Another option is something called bar mitts or pogies. These are big insulated covers that go over your bike handlebars. I bought my wife these $20 Lixda bar mitts and they allow riding in 20 F with just a pair of thin gloves underneath. They totally cover your shifters and any bells or eBike controls you might have, so you have to get comfortable with using those without seeing, but since you’re wearing thinner gloves under them it’s actually easier for your fingers to work these controls if you can visualize them. These cheapo bar mits are really quite warm and their reflective accents help you stay visible in dark winter nights. I don’t think I’d drop $100+ on fancier versions, but combining these with some cheap, thin gloves is probably the most economical way to keep your hands warm on a bike.

Hats & Helmet Covers

Along with your core, the other big thing you need to cover for cold weather cycling is your head. When temps start dropping below 70 F I throw on my helmet cover. I got mine free at the 5 borough bike ride in NYC years ago, but you can find an even better waterproof hiviz cover on amazon for just $11.

When it drops into the 50s I add a thin fleece helmet liner under my helmet. The feature I love for my liner are its ear flaps as cold wind on your ears really sucks. My liner is so old I have no idea where I got it or how much I paid for it, but I'm pretty sure it was cheap, maybe $10? It is pretty thin so I can wear it when it's a little cold without overheating. Another good option is a wrap around ear warmer as your ears will get coldest first.

For the 40s and below I switch to my thick turtlefur beanie. I'm not sure what it is about this hat that makes it so much better than other beanies I've tried, but with the helmet cover mentioned above it, it gets me through just about anything, even 0 F days.

The other option is to get a full on insulated ski helmet. I bought my kids ski helmets years ago and seeing how much they loved them I finally had to buy my own. I mistakenly didn’t get one with a sun visor, but I was able to jerry rig that by cutting up an old hat and mount a mirror on it too. This is now my winter riding head gear with a thin hat under it to cover my forehead on days under 25 F.

Face Covering

Below the hat, you'll also want to cover your face. Leaving little to no skin exposed is crucial to biking comfortably in the cold. One of the few benefits of COVID is that it's now much more normal to walk around with a face mask on. I expect to keep biking in my XL Enro face masks whenever it's 50's or below even after the pandemic ends. They totally eliminate chapped lips and wind burn and keep my face nice and warm even when the outside air is freezing (using some chap stick on your lips is still a fine idea though).

The big issue with masks is fogging glasses. I avoid this by keeping the top of the mask pinned to my face under my glasses nose pads. Somehow this isn't common knowledge multiple years into the pandemic, but if you haven't heard it yet now you know.

Down in the 20s I'll cover my mask with an old insulated half mask (here’s a newer half mask for $30). The must have feature for a half mask is velcro in the back so you can take it off while riding. Someone gave me a turtlefur neck gaiter once, but since I have to pull it over my head to remove it when I get hot I just can't ride with it at all. Even if you can stop to remove it, it will ruin your hair when you take it off. Just say no to neck gaiters and balaclavas and get a hook and loop insulated half mask instead.

Eye Covering

When it's really cold you're going to want to cover your eyes too. Having little to no exposed skin is the key to riding comfortably in cold weather. The new option I've been using for a few years now is a pair of Wiley X Tide prescription glasses (you can see them in my helmet and blue face mask pic above). These have a thin removable foam seal on the inside of the glasses and an elastic strap that attaches to the glasses arms and holds them tight on your head. I bought them primarily as safety glasses to use with woodworking, but these features let them function like slimmed down ski goggles too. I’ve ridden them down to 10F and they don’t keep my eyes as warm as ski goggles, but the ease of use of just throwing them on my face makes up for that. The foam insert is degrading a bit now, but apparently Wiley sells an upgraded foam insert for $20. The only real negative of the Wiley glasses is that being curved distorts my prescription in them a bit. They also fog a little if you wear them wrong, but that’ll happen with any glasses.

For serious warmth and the least fogging possible you’re really going to want some ski goggles. There are endless options for that, so I'll just say find a pair that works for you. Here are my son’s :).

Everything Below the Waist

The most neglected part of winter cycling wear is found below the waist. Since you're pedaling with your legs they can stay pretty warm on their own, but I still prefer to add some insulation and wind blocking to them. Feet are the last piece of the puzzle and you'll definitely want to keep them warm as well.

Lined Pants

The first thing most people think of if their pants are too cold is long underwear. Mr Money Mustache wrote a lovely ode to this in The Oil Well you can Keep in your Pants, but my leg hairs distinctly do not like tight long underwear so it's a no for me. Instead my secret weapon is flannel lined pants. These look just like normal slacks unless you roll up the cuffs to show off whats underneath. I have two pairs of flannel lined pants that I rotate in winter, one from Lands End, and a new fleece lined Eddie Bauer pair. You can also get flannel lined jeans if you want a bit more durability or a slightly different look. Whatever you do, make sure your legs have enough insulation for the conditions you're riding in.

Rain Pants Rule!

I'd never heard of breathable rain pants before I met my hydrologist wife, but now I never want to live without them. I had Marmot rain pants that lasted 6 years but waterproof membrane degraded in the area where my legs rub against the seat so I had to replace them. My new rain pants are the Endura Urban Luminite Pants. They’re designed for biking so hopefully they last longer, and they also have some nice reflective panels. Best of all they’re PFAS free and their adjustable cuffs are actually long enough for my legs.

Rain pants are great in the cold too. If it's below 18F I'll throw a pair on top of my flannel lined pants. This basically makes some DIY snow pants that are perfect for biking. Even if when its dry the rain pants act as a wind break and add a tiny bit of insulation that keeps my legs comfortable all the way down to 0 F. They're also great if it's warmer and raining and a worthwhile addition to any closet.

Socks

The right socks are also key or cold weather biking, and really just living in winter in general. I mostly use some generic thick wool + acrylic mix socks I got for Christmas a decade back. These are starting to wear a bit thin though, while my fancier and older Smartwool pair is still nice and thick. I’ve gotten some thinner Darn Tough socks that work down to around freezing and I like their lifetime warranty, though my Smartwools have lasted so well I don’t think it’s needed. Some cyclists recommend wearing sandals with waterproof socks in the winter, but that's a bit too out there even for me. I'll stick with the warmth of thick wool socks under waterproof shoes, then switch to thinner socks as the weather warms up.

Shoes

Finally, on top of socks you’ll need some shoes, they're the last critical detail for cycling. I prefer my shoes to not have laces for easy on/off, and the added benefit of never getting a lace caught in your chain while pedaling. I don't like being locked in while riding my kids around either and walking on clipless pedals is just a pain so I look for regular shoes that also work for biking.

During warmer weather I wear the wonderful Five Ten Sleuth slip ons because of their sole's amazing grip on my pedals (just make sure to order 1/2 size smaller than usual). I added a Power Grips strap to my left pedal to make it easy to reset the pedals at a stop. I didn't put one on my right so I could still instantly put that foot down when I stop. They sell these in pairs so doing it this way means you can equip two bikes with just one set.

Once it gets cold I’d break out my Staheekum Neoprene and rubber boots (currently $60, but I got them on sale for $36). The insoles are very comfortable and the insulation is decent. The only real problem is that they look boring and the pull tab has separated at the back of one of mine, but my rain pants cover that up, so I still wear them. Their soles don't grip the pedals nearly as well as my Five Ten's, but the Power Grips strap ensures that at least my left foot will never slide off the pedal.

When I’m riding somewhere that I need to look a bit more professional I throw on these insulated, waterproof Chelsea boots from Will’s Vegan Store. Their 12 is tighter than the Staheekum’s so they only fit thinner socks, but their insulation is better so total warmth is about equal. They’re definitely a bit pricey, but that’s what you pay for for such comfort, style and functionality.

That's it

Car culture has brought many people to a point where they simply don't dress for the weather any more. Wearing a t-shirt and shorts in December may work if you're inside a climate controlled box all day, but cycling forces you to actually engage with the weather. Luckily, there have been great advances in clothing technology that now make this easy, comfortable and cheap. Hopefully the above advice will help you get the clothes you need to be comfortable biking no matter the weather, and we can all profit greenly together.

Readers of this blog will already know that eBikes are by far the most efficient method of travel, but that I still decided to keep pedaling with my own muscle. I figured that I was gonna eat those extra burritos anyways, so why not use them for miles on my bike instead of inches on my waist? Well, COVID changed my whole mindset on this. Read on to find out why, learn the pros and cons of various eBike tech, and how I converted my own cargo bike to electric for under $700.

Why Electrify?

The first thing to ask yourself is why you'd want to electrify your bike. My main reason is that it'd get me places faster and more easily. This is especially in an area with lots of hills, which can be painfully slow on a loaded pedal bike. I used to slog my kids up hill at walking pace. It kept me strong, but it took a long time.

Riding an eBike up hills is a whole lot more fun, and it will likely lead to you using your bike instead of your car more often. Just look at these two graphs of the route I ride to pick my daughter up from school before and after I electrified my cargo bike. The eBike trip on the right has a far higher average speed. The eBike went 5 MPH so little that the graphing software literally removed that mark from the Y Axis on its graph! It also had 1/3 less travel time even with a lower top speed downhill, probably due to riding the brakes a bit to stay with traffic, and no sprints up near 20 MPH at the end like I did with the pedal bike (I must have been feeling energetic that day).

The trip graphed above takes a bit over 5 minutes by car, but parking, carseat buckling and then walking from the car mean the whole car experience is just about as long as the eBike's 7:03 total time if not longer. This parity of travel time is really a game changer. It eliminates one of the main reasons I would ever jump into my car for a short trip (cause I'm LATE!!!). The higher average speed of eBikes and easier parking mean that for short trips they're basically as fast, if not faster than cars.

In the gridlocked area of Northern Virginia where I grew up traffic was SO bad. I would often beat cars with my bike even on 10+ mile trips. Traffic there has only gotten worse since I left. Combine this with an eBike's higher average speed and it seems like in NOVA it would get you to your destination before a car for most trips under 10 miles.

This points to a key feature of bikes that car supremacy has blinded most Americans to. A 2 way protected bikeway can move more people per hour than using that same space for a single lane of car traffic. This is because even though bikes move more slowly, they take up far less space on the road and their lighter weight and greater visibility requires less forced stopping for safety. A lane of car traffic in a city only moves 600-1,600 people per hour, while a 2 way bike lane can move 7,500!

Car ads have confused us into thinking that the top speed of cars is the speed they continuously move at, but anyone who actually drives knows in their bones that this isn't true. Research shows that the average speed of car traffic on a given road network moves toward the speed of public transport/walking/bikes in that same area over the years. This is because more and more cars will clog the roads until they've made them so slow that other options are faster (AKA the Downs Thomsom Paradox). Using an eBike puts one less car on the road, reducing traffic and hopefully spurring our lawmakers to build more safe protected bikeways so there's even more cycling and less car traffic. This virtuous cycle ensures that the people who will still drive cars move along more smoothly.

There's also a financial aspect too. We know that eBikes get over 1,000 MPGe and require far cheaper maintenance than cars. Replacing car trips with eBikes will end up saving lots of money and reducing emissions. This is particularly true if you drive an inefficient truck. Maybe you need that truck for specific jobs, but saving it for those times and riding an eBike when the bed is empty will save tons of money!

The fun aspect just can't be ignored either. An eBike's assistance makes you feel super strong and speeds you up hills. You can still cut off the assist or go faster to get a workout, but that’s now a choice of riding and not a requirement. It makes riding feel as wonderful as it did back when you were a kid. When I bought my wife an eBike for her science work I took a few trips on it and just couldn't deny how fun it was. Seriously, find one to borrow or rent and you'll see.

The other big reason to electrify is to be able to haul seriously heavy loads with my bike. My usual cargo are my two kids, and they just keep growing every day. They're about 80 lbs together now, but they'll be over 100 in the blink of an eye and I wanted to make it easy to take them where they need to go quickly via bike. Beyond this my Madsen is rated for 600 lbs and I'd like to be able to truly haul that much up the hills of State College with it. The heaviest I've hauled so far was near 500 lbs of cargo + rider. While I could pedal that on the flats, steep hills were impossible and required me to walk it up with great difficulty. Adding electric assist should let me ride to the hardware store 5 miles away to pick up 200 lbs of rock, pipes, or lumber with my bike, a serious upgrade.

Why not Electrify?

Some readers will currently be muttering to themselves that adding a motor and a battery adds embedded energy to your bike and thus wastes resources. This is half true because while it does add embedded energy, that's small compared to the total emissions required to build the rest of the bike. It's half false because eBikes actually reduce emissions per mile compared to pedal bikes. Even if you still ride a pedal bike and only use the eBike to replace car/truck trips you wouldn’t have biked it will pay back it’s embodied carbon incredibly quickly (see my thread on this here).

There are other studies that claim that pedal biking has lower emissions, but when you read through them you see that this is only achieved by not counting the emissions embodied in the extra food you eat to pedal. Their basic premise is that in rich countries people are gonna eat whatever they want anyways. In my original eBike post I agreed with this, concluding I was gonna eat that extra burrito no matter what, so the emissions embodied in it belonged to my gluttony, not my biking.

The COVID-19 pandemic greatly reduced the amount of miles I put on my bikes and helped change my thinking around calories. As the disease spread I became largely home bound and quickly gained my own personal COVID 15. Actively deciding not to eat as much as I can all the time has helped me drop most of this weight over the past year and honestly it hasn't made me any less happy. I guess I'm lucky to have a body that doesn't require starvation tactics to drop weight (people whose bodies can maintain weight with even less caloric intake have the option to lead even lower emissions lives, but it seems pretty rough for them). I'm going to roll with what my own body is capable of and keep my emissions lower moving forward by sticking with my current diet and propelling my bike the extra miles I need to go with solar electricity instead of burritos. If you're not growing emissions free potatoes in your yard to power your pedaling it's worth a shot to see if you can reduce the amount of food you eat and add a little e-assist to pick up the slack.

But the Battery!?!

The final objection to eBikes is largely about the batteries they're powered by. As I detailed in Saving the World With an EV section of my EV post there are some legitimate problems with batteries, but they pale in comparison to those from fossil fuels. Batteries for eBikes are a special case because they don't have the same battery management systems found in large EV packs. There's no liquid cooling, or warming of your eBike battery and few limitations on how deeply you can discharge it. These can all lead to an eBike battery degrading much more quickly than those in bigger EVs. The industry is also still young, and many batteries are sold by sketchy firms, who have been known to put inferior cells into packs or bundle faulty chargers. This can result in eBike batteries catching fire while charging and even exploding.

One way to avoid a bad battery is to shop with big, reputable companies, but another is to buy a different battery chemistry entirely. The standard chemistry used in most EVs and eBikes is nickle manganese cobalt (NMC). It's so common than many people simply call it Lithium Ion or Li-Ion. But, there's a new option gaining popularity now called lithium iron phosphate (LFP or LiFePO4).

NMC can store almost double the energy in the same amount of mass as LFP so it has been the king for a while now. LFP main competitive advantages are that it basically can't catch fire from charging/discharging and it lasts far more charge/discharge cycles. That means a single battery will last for far more miles and won't burst into flames on you. LFP also doesn't use cobalt which means that it avoids the child labor issues that some cobalt mining has. Finally, LFP batteries also perform much better in cold temps than NMC. An LFP eBike loses less range when it's very cold out than an NMC one, though its battery still shouldn't be charged outside when it's freezing (large LFP batteries used in offgrid solar arrays have their own little heaters to enable cold weather charging).

For my eBike I selected a small 10ah 48V LFP battery (though in reality it outputs more like a 52V NMC battery because LFP cells have slightly higher cell voltage than NMC). It weighs just about the same as the 14ah NMC battery that my wife's Radrover came with, but that's without the hard plastic shell + locking hardware hers has. This little battery cost just $200 though, with charger! A Radpower pack costs $549, and you can easily spend $1k on a fancy high capacity NMC battery. If you need 100 miles of range from your eBike then that might be the right purchase to make, but in my case my town is only 5 miles across. It took me over a week to get my first full discharge of this battery using max assist on my heavy cargo bike and I still I got 29 miles of range. Even in winter I get like 20 miles per charge at max assist. LFP batteries are rated for 2500 charge cycles before they can only hold 80% of their initial charge. That means over this battery's lifetime it should be good for over 70,000 miles, more if I use lower assist levels. The electricity from my solar panels to charge this battery for 70,000 miles of range will cost under $100 total. Try finding a car that cheap to run!

How To Electrify a Bike

Okay, so now that I've sold you on eBikes, how do you get one? The simplest option by far is to just buy a new eBike. There are plenty of eBikes available for around $1k from retailers like Rad Power, Ride1Up, Propella, Lectric, Ariel, and more. The main issue with these bikes is that to hit this low price point they skimp out a bit on their non-electric components. My wife’s lab has a Radrover bike that we love, but it weighs 70+ lbs and literally has the worst bike shifter I've ever used. That doesn't mean it's unusable, it just means you often won't be able to shift into the lowest gear when you need to. The hub motor in its rear wheel does a great job of making up for this by being there to scoot you up hills even if you're in the wrong gear though, but the reality is my 1980s Cannondale has far higher quality components than this bike.

Upgrading to a Mid Drive Motor

You can buy an eBike from a major bike manufacturer that has truly quality components, but it's going to cost you over $2,000 (like the Giant/Momentum LaFree E+ or the Yamaha Cross Core) and you could easily spend over $4k (like the Specialized Turbo Como SL 4.0 or the Lemond Prolog). Moving up the price spectrum like this gives you bikes with better shifters and brakes, but also better motors. These high end bikes generally use mid drive motors (the Lemond is the exception, using an ultralight, low power hub motor). These motors use your bike's gearing so they can deliver more low end torque when you're in low gear, but also a higher top speed when you're in high gear. Check out this YouTube video if you want the full details (if you want a counterpoint on how hub motors can still be great check out GrinTech's writeup).

My main issue with the hub motors on fancy eBikes is that they don't seem very future proof. The bike frames are made with a very specific cut-out to fit the motor. This secures the motor better and lets them make it a bit smaller but if that motor dies in 10 years and there are no more motors of the same shape being produced then that frame becomes garbage. A good quality bike frame can last many decades, heck I still ride a 1989 Cannondale much of the time, so I don't want to spend big on a frame that might become worthless much sooner.

DIY hub motors completely solve the issue of a frame design becoming obsolete by attaching to any regular bike frame right where you pedals would have gone. You may have to do a little monkeying to reroute shifter/brake cables that run where the motor needs to go, but that's only true on a few bikes. My Madsen had this issue but as you can see getting around it wasn't too hard, I just moved them up over the bracket [UPDATE: with a bit of jiggling I managed to route the cables under the frame like they used to be, it brakes far better this way].

Adding a motor like this to a decent bike that you already own will always be the cheapest option. Even if you have to go out and buy a new bike it's still probably far cheaper to DIY that into an eBike than to buy the same quality eBike new. The question is which motor should you buy?

What Motor to use?

For my eBike conversion I selected a 52V Tongsheng TSDZ2 mid drive motor for just $425. I had to buy a couple extension cables to make it work with my cargo bike, but all that plus my battery was still under $700. That's a far cry from the official $1815 eBike kit from Madsen. This motor is a bit less powerful than the Bafang BBS02 motor that kit uses, but it's strong enough for my needs and it has 1 killer advantage over the Bafang, a torque sensor. Torque measure how much force your legs are applying to the the pedals and then the motor multiplies that force. This means you still have to actually work at pedaling while the motor makes you feel super strong. It also means that the motor responds very quickly whenever you increase or decrease your pedaling strength. They are usually only found on higher end eBikes with motors from Bosch or Shimano, but this tiny, cheap, Chinese motor has one.

Other eBike motors use cadence based sensors that track how fast you're spinning your pedals and use this to determine how much power your motor puts out. My wife's Radrover uses such a system. These might require 1 or two full rotations of the pedals before they change the power output of your motor, so from a stop on her bike I generally use the throttle to get rolling. Having a throttle guarantees that the eBike is either Class 2 or Class 3 and prevents it from riding on trails or roads that are limited to only Class 1 (like some mountain bike trails near my home).

Cadence based systems also really need brake lever sensors that cut motor power as soon as you brake. Otherwise you might stop pedaling and hit the brakes while the motor keeps trying push you forward for a second or two. Mid drive eBikes that use cadence sensors also often include a shift sensor that cuts motor power every time you shift to avoid damaging your gears. Torque sensor eBikes don't really need this as you can simply let up on pedaling a bit before you shift, just like on a normal bike, and the motor will almost instantly follow your lead. I like to leave a heavy foot on my left pedal when stopped at a light though, so I still appreciate the brake cutoffs that came with my TSDZ2 kit.

[UPDATE] After a year with my torque sensor I like it, but I don’t see it as necessary. The main use is when going slowly up hill following people walking. A cadence based bike is harder to do this with, but the torque sensor lets me do it easily. A throttle based cadence sensor eBike can slowly creep up hills too though and once you reach speed though there’s almost no difference between a torque sensor and a cadence sensor. Maybe just pick the cheaper option?

How Hard Was It?

The most technical challenge in converting my eBike came from the fact that the battery I bought was just a bare battery with wires coming out of it. I had to use my soldering skills to attach connectors to this so it could plug into the bike and the charger. I hope that LFP batteries with actual hard plastic cases and plugs start being sold in the US soon. Even if they don't soldering really isn't that hard, and you can buy all the tools I used for under $100. [UPDATE: Another dad replicated my setup without soldering by using push in wire connectors, I wonder if they’ll heat up, but so far it’s working for him]

The next hardest part of the install was removing the cranks and the bottom bracket of the bike. This required 2 special bike tools, a bottom bracket tool and a crank puller. These were intimidating to me because I'd never used them before, but it turns you basically just hold each with a wrench and turn real hard. I was lucky enough to get to borrow these tools for free from Penn State's awesome new Bike Den, but even if you have to buy them both new they're under $40 total.

Outside of those two pieces of complexity, I tacked on a bit of extra challenge by using my cargo bike instead of a regular bike. I did a little extra wiring to connect the 6V lighting output wires of the TSDZ2 kit to a buck converter that charges the USB battery my lights and DIY GPS tracker run off of. Then I had to figure out a way to mount the battery. Madsen's eBike kit includes a special custom built bracket for this, but it wouldn't work with my case-less battery. On a regular bike I could have just put this battery into a trunk bag on top of the rear rack, but obviously this wouldn't work for my cargo bike, which has a huge bucket on the back. In the end I drilled a couple holes in the bucket so I could tie the battery down under one of the seats in the bucket (see pics of this on my Twitter). Another hole let the power cable get to the motor and that was it. This mounting location keep its it out of sight and out of the rain (yay for Madsen's awesome weather cover). My son has complained that its "taking up space where his feet want to be" so maybe some day I'll have to suspend it from the seat itself so he can put his feet under it? [UPDATE: I did exactly this by strapping the battery to the underside of the seat, it fits there perfectly]. The most amazing dream would be rebuilding the whole kids bench seat to be the battery, but that's outside of my comfort zone right now.

After this was done all that was left was zip tying cables to the bike and setting up the handlebars. The main challenge there was to to pull off my bike's grips (shoving a zip tie between the grip and the handlebar makes this a lot easier) so I could replace my brake levers. [UPDATE: The brake levers that came with my TSDZ2 were crap, one of them literally broke off in my hand while biking, luckily I was able to stop with my second brake and carefully ride home. I may have caused this by overtightening them, but it’s never happened to me with another brake lever in the past. If I was doing it again I’d just keep my existing brake levers.] If I used a kit without brake cutoffs I could have avoided this step, but since this is how I carry my kids around I felt like cutoffs were required. [UPDATE: with a torque sensor cutoffs aren’t needed] The display itself could have screwed onto my handlebars without needing to take off my grips, and the only trouble I had with it was that I had to push scarily hard to get the plugs for the eBrakes fully seated into the holes in its back.

Luckily, I didn't break anything and the bike is now performing flawlessly. It took me a lot of research to decide upon this, but now that it's done I can't believe I waited so long. Riding my kids around with e-assist is wonderful. I expect it'll increase the miles, even I, a hardcore transportation cyclist, put on my bike. Hopefully this guide helps you to do the same, so we can all profit greenly together. [UPDATE: I replaced enough car miles with this to pay back it’s embodied emissions in just 10 months, I’ll have over 1,000 miles on it before I’ve had it a year, it took me 2 years to put that on the bike without e-assist]

Still struggling with the starter cord on your dirty old gas mower? It's time to recycle that loud and polluting contraption and move into the future with a quiet, cheap, and easy to use electric mower. The same is true for other lawn tools. Electric bush trimmers, leaf blowers and even chain saws are amazingly good now and you can use them all without going deaf. Still not convinced? Read on to find out more.

Electric = Easy

When my kids see old movies where people are trying to fix finicky gas mowers they're gonna be confused. Electric mowers are so incredibly easy to use. There's no mixing gas and oil, no annoying pull cord starter, no spark plugs to replace, nothing! Really the only maintenance is charging the battery and occasionally sharpening the blades. Electric mowers just plain work, and the same is true for pretty much all other electric yard tools.

It's hard to overstate the simplicity of electric mowers. Think about the gas mowers you've used in the past. Have you ever kept them running at idle even when you're not cutting grass because starting them was so annoying? With electric the start is just the push of a button, so if you want to take a moment to chat with a neighbor you just shut down the mower knowing that starting it up again will be easy and instantaneous.

The Quietness is Deafening

The other huge advantage of electric yard tools is how incredibly quiet they can be. There is some noise from the spinning blades and whirring motor, but it's nothing compared to the racket of gas mowers and leaf blowers. Above I noted how easy it is to shut off an electric mower to talk to someone, but the reality is you don't even have to. Electric mowers are so quiet you can actually chat to someone while mowing. Listening to your favorite podcast while mowing at volume levels that won't cause permanent hearing loss is now possible!

Gas lawn tools could be made to be more quiet, but doing so would add a lot of cost and cut their power. For decades we've accepted their cacophony because it seemed like the only choice, but now electric tools offer a quiet way out. Some places have proposed bans on gas lawn tools, but the reality is that a ban on overly loud lawn tools would have almost the same effect. Gas tool makers simply can't produce good tools that aren't ridiculously loud. People who are fed up at having their hearing damaged by their neighbor's lawn service will support the idea that lawn tools must be quiet, I know I would.

Electric Challenges

The main challenge electric yard tools have is that their batteries don't run forever. Even this isn't really an issue for a homeowners though. A rapid charger (like this one from EGO) can recharge a spent battery about as fast as you can use up a 2nd one. With two batteries and a fast charger you can literally do lawn work all day if that's what you're into. The 2nd battery adds some up front cost, but it will essentially double the life of your existing battery, so the total cost over time is pretty similar.

The next issue with electric yard tools is that some of their motors do not have enough power for the jobs you want to use them for. This sort of issue is more common with lower voltage tools. The reality is that yard tool manufacturers (both gas and electric) do a terrible job of explaining their products, and many times they're actively trying to trick their customers. I'll try and cut through their BS a below.

How to Pick an Electric Mower

The first electric yard tool that most people are going to buy is a mower. There are a lot of things to consider when doing this. You want to buy a tool that is going to be able to run long enough to cut your whole yard, or as much of it as you want to cut in one go. It must also have enough power to not stall out on your thickest grass. Unfortunately, manufacturers don't make this as easy as they should by advertising tools in terms of peak torque and batteries in terms of Volts (V) and Amp hours (Ah).

Gas mowers aren't much better. Their peak torque numbers given for RPMs their engines will almost never run at and there's nary a mention of their total fuel consumption. If electric mower manufacturers just published the peak power of their mowers in Watts and the total energy their batteries in Watt hours (Wh) it'd be much easier for consumers to pick a mower. Since they don't I'll try and explain how it works to all the normal people reading along.

How Long Can I Mow?

The main question most people have about electric mowers is many minutes of runtime their batteries have. To figure this out we first need to know how much power the mower is using on average. An electric motor's power output is measured in Watts (W). You can convert Watts to Horsepower if you want to be old-timey.

Most electric mowers have variable power output. They may run under 100 W with nothing to cut and bump up over 1,000 W when they detect thick grass and really have to work to cut it. If a mower's motor can't output enough Watts to cut a particular area of grass then the whole mower will stall out and stop. With a gas mower this is a big hassle because restarting it is so annoying. With an electric mower it just means rolling back an inch and clicking the start button to try again more slowly. If this happens frequently then you'll wish you'd bought a more powerful mower, but I'll get into that later.

At 300 Watt average output
40 V, 2.0 Ah = 80 Wh
80 Wh / 300 W * 60 mins = 16 mins

60 V, 2.0 Ah = 120 Wh
120 Wh / 300 W * 60 mins = 24 mins

80 V, 2.0 Ah = 160 Wh
160 Wh / 300 W * 60 mins = 32 mins

At 500 Watt average output
40 V, 2.0 Ah = 80 Wh
80 Wh / 500 W * 60 mins = 9.6 mins

60 V, 2.0 Ah = 120 Wh
120 Wh / 500 W * 60 mins = 14.4 mins

80 V, 2.0 Ah = 160 Wh
160 Wh / 500 W * 60 mins = 19.2 mins

Now, to be able to understand how long a battery will last we need to average its Watt power output across your entire yard. I wish manufacturers provided this info for a few known sample test yards and published it like the EPA publishes MPG for cars, but I haven't found any yet. From my own personal experience I'll say my mower averages about 300 Watts when cutting my grass on a normal day (fairly dry, not too long) and maybe 500 Watts when cutting tall wet grass slowly.

Lowering the blade of a mower increases the average Wattage a lot. I can imagine a push mower cutting the worst possible field of wet grass very low averaging over 1,000 Watts with peaks over 2,000 Watts. Of course cutting very low is also really bad for grass so you shouldn't actually do this. Still, it gives an idea of the power range a mower might use.

Once you know the average Watts your mower uses across your whole yard calculating the fraction of an hour your battery will last is simple. Just divide the battery's Watt hours rating by average the Watts it will consume. Unfortunately most lawn tool manufacturers don't advertise the Watt hour ratings of their batteries! Instead, they will confusingly tell you the Amp hours. Electrical engineers will know that Watts = Volts * Amps, but it's not common knowledge. Multiplying Amp hours by the Voltage of a battery will give its approximate Watt hours (I say approximate because the actual voltage of a battery is above its rated voltage and drops as it is discharged). An 80 V battery with the same 2.0 Amp hour rating as a 40V battery should actually have double the Watt hours and thus run for twice as long at the same Wattage. This is getting a bit into physics and math and if the green sidebar on runtime is still not clicking for you try watching this helpful Youtube explainer.

More Volts More Power

NOTE: High Voltage tools can often have more power because tools need thicker wven wire thickness and it will overheat and potentially start a fire. Lower voltage tools can be built with thicker wires to safely deliver the same Watts, but that adds to the price. The optimal engineering to get higher watts is to up the voltage. This is why you see really high power battery tools running at 80V or even 120V. A Porsche Taycan electric supercar actually runs at 800V and can deliver 620,000 Watts of power.

As we saw above, higher Voltage batteries will store more Watt hours for the same Amp Hours. This might not translate into as much extra runtime as you'd expect though. That's because higher Voltage tools often also support higher max power output (aka more Watts). If your mower has more power you can push it faster over your grass without it stalling out. Pushing faster will both reduce the time it take to mow your yard and increase the average Watts your mower puts out while mowing. That should theoretically allow the same battery to cut your yard fast at high power or slow at low power. But, in reality, the higher power models probably waste a bit more energy and thus have shorter run times for the same amount of Watt hours. Higher power mowers are also more likely to be self propelled. Moving a mower takes a lot of energy and will seriously reduce battery run time, but big battery electric mowers can handle it.

One Battery To Rule Them All

The most useful thing about manufacturers advertising the voltage of their various batteries and tools is that it lets you know which tools can be run with the same battery. In general, all tools made by the same company at the same voltage can run off the same batteries (there are some exceptions though, so read the fine print). If you buy a 40V Greenworks mower with a battery it should also be able to power a 40V Greenworks leaf blower, but not with their 60 V string trimmer. This can be a huge money saver as the battery is where most of the cost comes from. It's how I was able to buy my kid a leaf blower to play with for just $50 and a 20 inch pole hedge trimmer for $88.

The tools in a 40V line will likely be cheaper than those in an higher voltage line, but as I discussed above they're also likely have less peak power. As someone who's patient and leaves my grass fairly high, max mower power doesn't matter much to me. If I need an electric chainsaw in the future though I may regret not buying a 56V EGO mower to start the EGO chainsaw is top notch. There are even some 120V tools coming to market, but I wouldn't be seduced by their higher voltage unless you really need the highest power output.

If you already have cordless drills from company like Dewalt, or Makita you can actually use their batteries in cordless mowers from the same manufacturer. Dewalt offers a mower that connects 2 20V Dewalt batteries run in series to get to 40V. Of course the tiny 20V 1.5 Ah batteries on my drill and driver set would only run this thing for a couple minutes. But, if I had Dewalt's amazing cordless miter saw I could use its big batteries in their mower. Still, reviews of purely lawn tool focused manufacturers like Greenworks and EGO tend to be better than these workshop tool makers who have expanded out into lawn tools. If you already have a big workshop and a lot of batteries from one of these brands, adding some lawn tools from them without buying new batteries might still be a good choice, otherwise stick with lawn focused companies.

Electric Costs Can't Be Beat

Of course it wouldn't be a Profit Greenly article if I didn't discuss the costs of these tools. As we've seen with electric heat pumps, bikes and cars the price to run electric lawn tools is unbeatable by gas. The 40 V 4.0 Ah battery that my mower uses contains 160 Wh of energy. My utility is now charging 9.5 cents for 1,000 Wh of energy (down from 10.5 cents pre COVID) and my solar panels bring my effective personal energy price down to around 7 cents.

On a dry day I can mow my entire 0.2 acre yard and still have battery left, on a wet day with thick grass I might need to use this whole battery plus my backup 2.0 Ah battery to get my yard done. That's a total of 240 Wh of energy in the worst case. So, the high end cost of electricity to mow my lawn even at last year's higher energy prices is a mere 2.5 pennies!!! And that's on a bad day. On a good day with solar it can cost as low as 1 penny. With gas currently at $3 per gallon I'd have to mow my lawn between 120 and 300 times to spend as much on electricity as a gallon of gas costs. I have a small 0.2 acre lawn, but still this gallon of gas would probably only mow it 10-20 times.

Eventually I'll have to replace the battery for my mower, but it's already gone 3 years without any sign of slowing down. I expect it'll last around 10 years, but we'll see. When it does finally die replacing it will likely be the first real maintenance cost I experience with this mower. There are already 3rd party replacement batteries for $60. With lithium ion batteries dropping in price so quickly I don't expect this part will cost much by the time I do need to buy it.

Of course this fuel comparison doesn't include other important costs from maintenance. I've had my electric mower for 3 years now and have spent exactly $0 and 0 hours on maintenance for it. Can you say the same for your gas mower? I guess if you count the time it takes me to put the batteries in and out of the charger I may have spent 1 hour total on maintenance over the last three years but that's really it. Winterization is as easy as drawing the battery down to half full and taking it inside my house for the winter. The leaf blower gets the battery down to half very easily at the end of my fall raking.

The initial price on my mower was also exceptional. I bought the 20 inch Greenworks mower with a 40V 4.0 Ah battery for just $194.67. That's less than the initial price of a lot of gas mowers and below what people spent to DIY an electric mower 13 years ago. This mower is currently selling for $380 on Amazon, and I don't recommend paying that price for it. You can to upgrade to a 56V 21 inch EGO mower with a 5AH battery for just $399 at Lowes right now. Alternatively, Lowes Kobalt brand mowers actually seem to just be blue colored Greenworks mowers. I wouldn't be surprised if they were made in the same factory even. Right now they're selling a 40V 20 inch model with a 5Ah battery for $249 and a 40V 19 inch model with a 4Ah battery for $199. Either of those might be good for you, or you could just wait for another Greenworks sale.

If you are buying a new gas mower it will likely cost as much or more than I paid for my Greenworks. The cheapest gas mower at Lowes is a 20 inch 170-cc Yardmax model for $169. That saves you $25 up front compared to mine, but of course you need to add a quart of oil to it which is $4. The manual says to change this completely after the first month, and then again every 3 months after that. So at the end of the first summer you've spent $12 on oil. You're also supposed to replace the spark plug and air cleaner every 6 months, and of course there's gas too. Basically after 1 season of use this cheap gas mower will end up costing more than my electric. After 3 years this cheapo gas model probably has a total cost of over $250.

The nearly non-existence fuel and maintenance of an electric mower mean that I still haven't put $200 into mine even after using it for 3 years. That's cheaper than this dinky little Yardmax. Even if you spring for the $399 EGO it's still going to be less than a similarly capable gas mower. You'll have to do the math for your own use case, but I bet it turns out that over the life of the tool electric will turn out cheaper than any comparable gas model.

The True Price Champions

There are three other kinds of mowers that can actually be cheaper than even the great deal I got on my battery powered model. The first of these is a corded electric mower. You can literally find this for under $100, like this Sun Joe Model. They actually have less max power than the stronger battery mower options and you have the hassle and danger of running an extension cord out to them. I don't recommend them, but they sure are cheap and I've known people who loved them.

Next up is a reel mower. At $65 reel mowers are the cheapest up front cost. With no motor or batteries it is also the true greenest choice in lawn cutting. These models just use your own muscle power to spin their blades fast enough to cut grass. Sometimes I wish I'd tried one of these out on my lawn before buying my electric mower, but the amazing deal I saw came before I had a lawn to mow so I didn't have the option. The issue with Reel mowers is that being harder to push means that they take longer to cut your grass. They also force you to workout more, but that actually seems like a benefit to me. If you value your time monetarily though then the total cost of a push mower can actually be quite high.

Electric robot mowers can actually be the cheapest when time is factored in. These models have high purchase prices, often over $1,000, but if you truly value your time though they can pay for themselves. Rather than use your own hourly salary to capture time cost it's best to compare them to a lawn service. I was forced to pay $50 to have my yard professionally mowed or get fined by my city when I was out of town once (crazy I know). A $1200 Husqvarna 115H robot mower would have to mow my lawn 24 times to pay for itself at this rate. If I'd been able to find some neighborhood kid to mow for $20 it'd take 60 mows before the Husqvarna paid for itself. That's still probably only 2-3 years.

Robot mowers are also all electric, so they have the same low operating costs as my own electric mower. Unfortunately, you can't re-use their batteries in other tools so there are fewer side benefits. Of course, their main side benefit is saving your time. If your time is so valuable that you're paying for a lawn service, or you're just physically incapable of mowing then a robot mower could be your true lowest cost option.

But is it Green?

The final question is whether a battery powered mower is truly green. The true greenest option is to simply not have a grass yard (there may be other social benefits to not having yards as well). Unfortunately, most homes in America do have grass yards and removing them is explicitly banned in many communities. Even in a magical world without lawns we'd still want public green spaces at our parks mowed, so emissions from lawn tools will still be with us. In the cases where lawn mowers must be used switching to battery powered equipment is definitely far greener.

I'm sure some readers are now thinking about the horrors of lithium and cobalt extraction. There are real issues with these, but as I explained in my EV post they are overblown and quickly being corrected. A mower also only has around 1/500th the battery capacity of an EV so the magnitude of its waste is much lower. On the flip side small gas engines in mowers and leaf blowers are actually crazy polluting. They can actually create more emissions than a full size truck!

We're not talking CO2 here (which trucks definitely emit more of), but other pollutants like nitrous oxide (NOx), and carbon monoxide (CO). These are bad for your health and certainly not something you want to be breathing in while you're huffing and puffing doing lawn work. They're also not good for the environment either, with every lb of N2O released into the atmosphere causing as much warming as 298 lbs of CO2. Again, car engines are run for so much longer than these small motors that their total greenhouse impact is far higher, but these little gas motors do a lot of damage in the short periods when they're run. Noise pollution is also a real thing, and while it's not as deadly as carbon monoxide it certainly is annoying. Now that electric yard tools provide cheaper, easier, quieter and cleaner alternatives there's no excuse to stay with gas. Make the switch to electric and start to profit greenly with me.

UPDATE 2023: I’ve learned one more thing about the road damage formula. It’s not just axle weight to the 4th power, you must then multiply that by number of axles. Since most bikes and cars have 2 axles most of the numbers in this post stay correct, but a 5 axle big rig will actually do 2.5x more damage than calculated below. Adding more axlese still reduces damage by better distributing weight and lowering the number being raised to the 4th power, but it isn’t magic.

Been on a road lately and noticed how absolutely busted it was? Have you also noticed how vehicles today are far larger than in the past? These two things go together because vehicle weight is the main factor that determines road damage. State legislatures across the country are ignoring this simple fact and instead trying to blame EVs or even bicycles for our crumbling roads. The smarter/fairer way to fix our roads is by switching to a fee based on the actual road damage that vehicles cause. Replacing gas taxes and EV road fees with this would lead to a fairer and better system. Drivers who are currently freeloading off our system will pay more, but the rest of us will profit and the world will become greener. Read on to find out how it could all work.

How Roads Get Damaged

Note: The above chart from streets.mn incorrectly assumed that a 9 ton big rig would have 2 axles holding 4.5 tons each. Big rigs actually have 5 axles so it needs to be 22.5 tons to have 4.5 tons per axle and do 410 times as much damage. I've corrected this on their otherwise wonderful chart.

The first thing you need to know to understand my proposal is how roads actually get damaged. The exact formula for road damage depends on a lot of factors, but the most important two are axle weight and miles traveled. When scientists did a thorough study of how quickly roads deteriorated in the 50's they found that road damage increases by axle weight to the 4th power. There's some debate as to whether road damage is primarily due to axle weight or to total vehicle weight but the conclusion either way is that heavy vehicles do far more damage to roads than light ones.

A 4.3 ton Hummer does more damage per mile than 21 2 ton passenger cars. Miles traveled increases road damage linearly, so one car driving 200 miles does as much damage as two cars driving 100 miles each. The 4th power rule still applies so a single 22.5 ton shipping truck with 4.5 tons per axle does as much road damage in 1 mile as a 2 ton passenger car does in 410 miles. Most states in the US limit total truck weight to 40 tons and a 5 axle truck carrying this much would do as much damage per mile as 4096 2 ton passenger cars! There are a fair number of exceptions to this, like Michigan allowing 82 tons per truck, but they still generally limit axle weight to around 10 tons or less.

Age and Weather Deterioration

Even if no vehicles drive along a road it will slowly degrade. Roads in Hawaii that have been traffic free for decades due to volcanos show just how long a road can last if nothing is driving over it. The 30-50 year old road pictured here is looking pretty good, outside of the giant mass of lava rock on top of it. I'm unsure how long it will last in this state of disuse, maybe 100 years? Certainly far longer than the 18-25 years engineers expect roads with a usual amount of traffic and maintenance to last. It's fair to pass the initial construction costs of a road to all users, but the costs created by actually driving on it dwarf these and our fees should account for them properly.

The Gas Tax Can't Cut It

Now that you understand how road damage is actually caused you can start to see how the gas tax can't fairly pay for our road maintenance. Big shipping trucks average around 6 MPG, with 7.25 being consider quite good. US passenger vehicles averaged around 22 MPG in 2017. That means that shipping trucks use a bit under 4 times as much fuel for every mile they travel, but that doesn't come close to accounting for the 400-4,000 times as much damage they often do per mile. They do face other fees, like a 32% higher tax on diesel than on regular gas, but these do not come close to matching the extra damage they cause. Big trucks drove a bit over 1 mile for every 10 miles light duty passenger vehicles traveled in the US in 2018 but do far more than 10 times the damage of passenger vehicles. They're freeloading on the current highway funding system.

Of course Passenger vehicles have also ballooned in size and weight. Americans have made a massive shift to larger SUVs over the past few decades. These accounted for 50% of new autos sold in the US in 2019! The engines of these vehicles have also become more efficient, burning less gas to pull the same amount of weight, but the gas tax has remained largely unchanged in most places. A heavier truck that gets the same MPG as an older lighter model will pay the same amount of gas tax while causing significantly more road damage.

All of this means that in America the gas tax hasn't fully funded roads in decades. When you look at it comprehensively road funding costs every household in America over $1,000 beyond what they pay in gas taxes. This doesn't even include the local property and sales taxes that generally fund local streets. People are on the hook for this even if they don't drive cars at all. Think about that next time someone tries to tell you that pedestrians and cyclists aren't paying their fair share for roads.

EVs Complicate Things

The upcoming shift to electric vehicles will provide an even greater challenge to road funding as they don't use gas at all and are often heavier than their gas counterparts. Rather than fairly charging EVs for the road damage they cause legislatures across the country are tacking flat fees onto EV ownership. These fees range from $50 to $225 per year currently and some states have proposed fees as high as $1,000/year! It should come as no surprise to readers of this blog that these fees are often backed by money from fossil fuel interests that are trying to slow EV progress.

State EV fees will almost never correctly charge drivers fairly. For example, my dad payed Virginia an $88.20 fee for his EV last year. If he'd just kept his old gas car and used it for the same driving he'd only have paid around $25 in gas tax. This is exactly what fossil fuel lobbyists are hoping for when they get these fees passed. Of course being flat fees means that they may also undercharge some road users. The shuttle company that drives Teslas over 100,000 miles per year will never be charged appropriately by a flat fee.

These flat fees also fail to address the elephant in the room, vehicle weight. A 6,600 lb Cybertruck will be charged the same as an 1,800 lb Aptera even though it does over 180 times more road damage per mile. That'll just keep pushing Americans to buy bigger and heavier vehicles that do more damage to our roads. This will eventually result in another shortfall of road funding in the same way our switch from small cars to huge SUVs has. EVs can be made smaller and lighter, but this won't happen so much if heavy vehicles aren't charged their fair share of road maintenance fees.

Hidden Costs of Big Trucks

The trend towards bigger vehicles is doing a lot more than just destroying our roads. To start with the obvious, big SUVs take more materials to build. Kees van der Leun did a quick estimate in 2020 and found that around 9 million extra tons of steel was used to supersize cars into SUVs that year. This isn't all the steel used in SUVs, just how much extra they required compared to traditional cars. To contrast, every wind turbine built in the entire world in 2019 combined probably only used about 6 million tons of steel. That's a lot of material to be wasted on big vehicles that have just one occupant and no load much of the time.

Safety is another big reason to get drivers to switch to smaller vehicles. Many SUV owners bought their vehicles for safety, but the reality is that they're just as risky in a crash as smaller cars (ask Tiger Woods). The sad flip side is that SUVs are far more likely to seriously injure or kill the people they collide into, particularly if they have bull bars on them. Part of this risk is accounted for in higher SUV insurance costs, but much is simply born by society through hit and runs and unpaid medical bills.

Note: Buying a cheap used Leaf to use for trips that don't require hauling saves so much on gas and maintenance vs a big truck that it is essentially free and will quickly start saving the owner money.

Bigger vehicles often have big hoods in front that make it harder to see and avoid hitting things that aren't so tall, like kids. The new post office truck is a welcome exception to this trend, but consumer trucks are in a race to make the largest, most vision obstructing hoods possible. This is part of why vehicle crashes are the leading cause of death for kids in the US. If a road use fee that included axle weight to the 4th power caused truck drivers to only put miles on their large vehicles when they really needed their size it would have benefits far beyond paying for road maintenance appropriately.

What About Work Trucks?

A common complaint about a weight and mileage based road damage fee is that it would unfairly penalize those who use heavy trucks for work. Those who are simply using their 2 ton pickups as commuter cars can follow Mr Money Mustache's work truck advice and switch to smaller vehicles, but what about the people who actually need to haul literal tons of stuff? The simple answer is that they should pass the cost of the damage their vehicles cause on to their customers directly. This would increase the cost of things like construction and fracking that truly require large trucks by taking away the subsidy they are currently receiving from all of us when we pay to fix the roads that they destroy. The people who are actually requesting those services should be the ones who pay for the road damage the trucks they require cause and the rest of us should keep our money.

Beyond the simple fairness of appropriately charging large trucks, a weight based fee could also encourage better ways of doing things. Light weight materials would cost even less to ship and thus become more likely to see use in buildings and products. Rails can also handle huge weights with less maintenance than roads. If roads aren't so subsidized efficient trains may transfer more of our freight. Because of the 4th power rule two smaller trucks combine to do less damage than 1 large one, so shipping companies could start downsizing trucks and employing more drivers to lower their road use fees. In densely populated areas this could go even smaller like the 10,000 electric rickshaws Amazon is deploying in India, or the delivery cargo bike trailers that have started popping up all over Manhattan. These smaller vehicles do less damage to roads and also cause less traffic. Think of how frequently delivery trucks block full lanes of traffic while dropping off a package. Bikes can avoid disrupting traffic by pulling directly up to someone's door. This also saves delivery workers time, with many actually delivering more packages per day after switching to cargo eBikes. Of course I'd be remiss if I didn't refer back to my own post which explains how these eBikes likely get close to 1,000 MPGe, an efficiency level no car or truck will ever achieve.

How to Implement It?

The next major complaint about a mileage based road damage fee is that they'd be hard to implement. The straw man argument made here is that they'd require privacy invasive GPS trackers on all cars. This of course ignores the fact that most people have already accepted having their locations tracked by Google and other tech companies for years. Also, a mileage based fee does not require that level of tracking. In many states the odometers of cars are checked during their annual safety inspection. In the rest odometers get logged whenever a car is sold. These existing practices can be used to charge people for the miles they've driven without invading their privacy.

We could implement GPS tracking for super heavy cargo trucks since they do so much more damage per mile. Reporting where a truck has driven is already somewhat required by IFTA fuel tax reporting and many already have GPS trackers because of this. The privacy implications of this feel less fraught as these trucks are driven by employees on the job, and not by people just living their daily lives. The cost of GPS trackers is so low now that this could be done very cheaply, and it would allow precise delivery of funds based on where trucks are traveling. When Amazon opens up a shipping yard in your town there won't have to be a huge political fight to get them to pay for the extra road damage their trucks will cause, it'll just be recorded on the GPS and paid accordingly.

The other big complaint is whether we'd have to start weighing our cars. This is disingenuous and simply taking their gross vehicle weight should be enough. For light trucks we could add some percentage of their payload capacity, say 50%, to this figure. That'd give even more disincentive for people to drive huge trucks around with nothing in the bed, and might actually spur manufacturers to make some decent smaller trucks again. These aren't the only possible answers, but they seem easy enough and show to implementation of a road use tax is do-able.

Wrap Up

Once we open our eyes to how the true costs of our roads are incurred a weight and mileage based road fee is pretty obvious. Yes, there can be quibbles about how the cost of initial road construction should be factored in, but the basic idea that heavier vehicles should pay far more per mile driven is sound. The monetary and environmental benefits of encouraging lighter vehicles are huge, and we need to stop missing out on them. If it helps properly fund our roads and increase our safety at the same time, all the better.

I've been haranguing my mom into buying an electric car for years now. The other day she had a Zoom with some friends and shared a bit of what she'd learned, they were incredulous. This drove home just how little the general public really knows about EVs these days. This isn't really their fault. People are busy, progress has been super fast, and oil related companies spend millions on huge misinformation campaigns to keep us burning gas. Price has also been an issue and early EVs cost so much that they were easy for many to ignore. I drove a gas car myself until nearly a year ago when a low priced Chevy Bolt finally got me to switch. After months of driving my new EV, I can clearly say that if you're buying a new car it should be an electric car.

UPDATE: Jesse from the Best Interest blog published a write-up from me on how the Chevy Bolt might just be the cheapest new car in America right now with a lower total cost than even the cheapest gas car. It's in the Cheapest Car in America section of his The True Cost of Car Ownership post. Go check it out.

Living With An EV

EVs To Check Out:
Aptera
Chevy Bolt
Ford Mach-E
Kandi K23, K27
Nissan Ariya
Tesla 3, Y
VW ID.4

Even normal people have probably heard about how fast Teslas are these days. They might not realize that the Pike's Peak hill climb record was just taken by an EV this year and will likely never be held by a gas car again. And speed isn't just for expensive EVs anymore either. My cheap little Bolt does 0-60 in 6.3 seconds. That's as fast as a brand new Subaru BRZ or a 90's Supra. Those cars both corner better but the Bolt will actually be faster in normal use. This is because to get full power out of a gas car you have to rev your engine to the red line and drop the clutch. With an EV you just stomp on the pedal when the light turns green and leave everyone in your dust. If you haven't yet felt this for yourself just go and test drive one- you'll be amazed how fun they are.

The other incredible thing about EV performance is that flooring them barely affects their efficiency. Everyone knows that when you accelerate hard in a gas car the MPG drops a lot. With an EV though, hard acceleration only creates a little extra waste heat in the car's battery and wiring, and that will barely drop the efficiency (a high power Tesla constantly going all out it may wear down components faster than you'd like though). Turning on the heat, slamming on the friction brakes, or even running the AC will all hurt efficiency more than flooring an EV. What this means in practice is that frugal drivers like me will finally feel free to jackrabbit start out of every red light and up every freeway on ramp. I wonder a bit about the safety implications of this, and try to use this power carefully, but the fun of it is undeniable.

Living with an EV isn't just about fun driving though, it's also about saving your own time. A gas car, even a hybrid, constantly forces you to get gas. With an EV it only takes 2 seconds to plug the car in at home leaving it fully charged and ready the next day. There's no more driving your car down to E and trying to find the perfect time to fill before you run out of gas, or searching for the cheapest station. The whole narrative on how EVs are less convenient to fuel than gas cars is dead wrong when you're charging at home and people need to realize this.

There are a few times when you do have to plug in on the road though and these are currently more annoying than fueling with gas. To make it easy to sort through the confusion, apps like Plugshare let you easily see only the chargers that will work with your car. Because we're still at the beginning of the EV revolution, using an app like this is pretty much required to plan out longer trips. Being at the beginning also means you'll find things like chargers that are literally giving away electrons for free! Still, researching a route is a bit more annoying than the ubiquity of gas stations. Unless you're a traveling salesman though you won't be doing this much and many EVs have custom apps in the car to make this even easier. The time you'll waste planning your few long trips is likely far less than the amount you're probably wasting right now filling up gas for local trips. Also, as I explain in my EV transition post, the ease of refueling will likely flip as gas car's market share drops and gas stations close, so it won't always be harder to fill an EV.

The final annoyance with charging on the road is how long it takes. This can vary a lot depending on what type of car you have and how empty it's battery is. Every EV has a certain number of kilowatt hours (kWh) in its battery and a maximum kilowatts (kW) of power it can accept. My Bolt has a 66 kWh pack and accepts 50 kW of charge. This is where a little bit of understanding of electricity comes in. If I charge at 50 kW for 1 hour then I will have added 50 kWh of energy to my battery, if I only charge for 1/2 hour I will have only added 25 kWh. The realities of battery chemistry mean that my pack can't take 50 kW of charge the whole time. It accepts a bit more than this when it is low but the amount of power it can take starts tapering off as the battery gets more full (see the red dots in this graph).

The other reality is that EVs have different efficiencies, depending on the weather. The tons of waste heat that spills off a gas engine just doesn't exist for an EV. That means that turning on the heat in an EV is turning on an actual heater which can seriously drop your efficiency. My Bolt gets over 4 miles/kWh on a nice spring day and under 3 on a frigid winter day. Charging my battery from 20% to 40% will add about 13.2 kWh of energy to it in about 15 minutes. In the Spring this adds over 50 miles of range but in the winter it's under 40 because of my lower miles/kWh.

Speed also affects how far an EV can go per kWh. Since wind resistance increases as a square of car speed going just a little slower can save a lot of energy. The numbers I gave above are for regular highway speeds (mostly 55-65 some 70-75). If you drive in the 80s then efficiency and range will drop. If you are driving slower then they'll increase. These crazy guys drove a Tesla 3 under 20 mph for over 30 hours and got over 9 mi/kWh! This leads to the counterintuitive, but welcome reality that an EV plodding through a traffic jam can actually drive more miles than one doing 80 on the open road.

Even my "long" drives are generally under 300 miles, so most of my fast charging stops are for less than 10 minutes. My Bolt adds about 30 miles of range in this time, just enough to get me where I'm going. If I was charging more I would consider a car that accepts a higher rate of charge. A Mach E can accept 150 kW, so it can take energy 3 times faster than my cheap Bolt. It's bigger and heavier than my Bolt and thus less efficient, but this is still around 50 miles of charge in just 10 minutes. Tesla's new 3 and Y can both accept an incredible 250 kW of power. The 3 is also extremely efficient, meaning that it can add over 150 miles of range in just 11 minutes of charging! If I took a lot of long trips then the new Teslas would be at the top of my list. As it stands though I've only spent a few minutes fast charging in the last year so I'm happy to have saved tens of thousands of dollars by choosing the Bolt.

That's kind of it on living with an EV. The basics are that they're fun to drive, easy to fill up in your garage, less stressful in traffic and just a little annoying to charge on longer trips. The problem is that people base their entire car buying experience on optimizing the one long trip they take each year instead of optimizing the shorter trips they take far more frequently and waste more time with. When you look at it with this perspective, an EV is just plain easier than a gas car in total.

Saving Money With an EV

Here on Profit Greenly I like to focus on cost, so of course I can't forget the price of the car. I'd been dreaming of an EV (electric vehicle) for over a decade, but the price had always held me back. Luckily the price of batteries has fallen like a rock in those years, in 2010 the average pack cost over $1,000 per kWh, in 2020 some companies were building packs for just $100/kWh. The 66 kWh pack in my Bolt would have cost over $66k in 2010 but GM probably spent about $135/kWh on batteries for 2020 Bolts, so the pack in my car was likely around $9k. This is part of why they've been able to discount the car so much. In 2017 they sold it for $40k, I bought mine a year ago for $26k and thought it was a great deal and now Bolts are going for just $23k! Researchers say that EVs will have the same initial cost as gas cars by 2023, but with the Bolt selling for these prices I think they're already there. A Bolt is far cheaper than the $38k average new car price in America and still less than economy cars like the $24k Hyundai Ioniq and Toyota Prius. There are a few cars that are still straight up cheaper to buy than the Bolt (like a $13k Spark or a $16k Mirage) but they are smaller, slower and cost more per mile to run. When you look at total cost over the life of the car you may be spending even more money on these cheapest of new gas cars than you would on a Bolt, especially if they eventually need a lot of repairs.

Electricity Vs Gas Price Per Mile

Fuel cost per 100 miles 
Bolt EV:
29 kWh*$0.105/kWh 
= $3.05 Home Charge
29 kWh*$0.07/kWh 
= $2.03 Solar Charge

58 MPG Ioniq:
$2/gal/58 MPG*100
= $3.45/100 mi

24 MPG Average Car:
$2/gal/24 MPG*100
= $8.33/100 mi

Fuel for EVs generally costs far less per mile than for gas cars because they're so much more efficient. The Bolt is rated at 118 MPGe (or 29 kWh per 100 miles) far higher than any gas car. Even the most efficient new gas car, a 58 MPG Hyundai Ioniq, is nowhere close. The issue is that 1 gallon of gas contains about as much energy as 33 kWhs of electricity but it does not usually cost 33 times more than 1 kWh. If gas is cheap relative to electricity then a hybrid that is far less efficient than an EV can still get similar fuel per mile costs.

One great way to ensure that your electricity is cheap is to install your own solar panels as I detailed in my Solar ROI post. Another way is to see if your utility offers a time of use rate plan that sells power for less at night. In places like Texas you can actually get a rate plan that gives away electricity for free at night. This is because Texas has a ton of wind generation, and they often make more power at night than people there currently use. To avoid having to waste money turning off generation at night they just give power away then for free and charge more during the day to make up for it. This is the plus side of renewable generation's intermittency, as it creates times when power is essentially free. Getting on this sort of amazing rate plan would give an EV an unbeatable fuel cost of $0/mile if you charge it at night!

Fast Charging Costs

The one time a gas car has a chance of competing with an electric car in terms of fuel price is when the EV is using an expensive DC fast charger. I like to use the Electrify America network, which charges $0.43/kWh in most states now. In PA they still charge by the minute, and their $0.16/min here equates to between $0.18 and $0.32/kWh for my car depending on how full the battery is (remember that batteries can charge faster when they're less full). The top end of these PA prices costs $9.28 per hundred miles and in other states it can be over $12. Those are terrible prices but this is the top end cost and most charging is done cheaply at home. If you really do charge on the road a lot, you can pay a $4 monthly membership fee to get 25% off these prices, or get a Tesla and use their cheaper Supercharger network. If Aptera is actually able to deliver their amazingly efficient EV that gets 10 mi/kWh then that'd drop per mile price back below gas cars. Of course if you have 1,000 miles in your car's battery and get 10-40 more each day from the sun, will you ever even plug in? For me these fast chargers are only used for a few long trips each year, and honestly I'm happy to pay their high rates to ensure that I can get to all the places I want to go.

Fast Charging % to Equal $2/gallon Gas 

58 MPG Ioniq vs 
Home Charging:
(3.45-3.05)÷(9.28-3.05)=6%
Solar Charging:
(3.45-2.03)÷(9.28-2.03)=20%
Free Night Charging:
(3.45-0)÷(9.28-0)=37%

Avg 24 MPG Car vs
Home Charging:
(8.33-3.05)÷(9.28-3.05)=85%
Solar Charging:
(8.33-2.03)÷(9.28-2.03)=87%
Free Night Charging:
(8.33-0)÷(9.28-0)=90%

When I say I only take a few long trips each year, I really mean it (read my elegy on why most travel isn't worth it to see why). This has become even more true with COVID. I've driven under 4,000 miles on my Bolt over the past 11 months using just 1140 kWh. Under 40 of these kWh came from expensive fast chargers, a measly 3.5% of my total. Part of this was due to me finding a few fast chargers that were free (try finding a gas station that gives away free gas) but the bigger part is that even the "long" trips I take to visit family are only a few miles longer than the Bolt's full range, and often well under it. Recharging fully at home every night means the car is always full so if it can make the trip on a full charge, then no fast charging is needed. People who do a lot of very long trips may use a higher percentage of fast charge kWhs, but those same people probably also drive their car around town more than I do since I bike most short trips. Those around town miles would keep the percent of kWhs from fast chargers down so their EVs $/mile of fuel would probably still be low. As you can see in the math on the side I'd have to fast charge over 20% of my kWhs to make my Bolt cost as much to fuel as an Ioniq, 87% when compared to an "average" 24 MPG car.

Fuel isn't the only per mile cost for a car though. Maintenance is often an even bigger cost over the life of a car. The maintenance schedule on a Chevy Bolt is amazingly empty. On a gas car you have constant oil changes, brake servicing, transmission issues, exhaust problems, spark plugs, belt replacements and eventually failures of sensors inside the engine. Most of this stuff just can't go wrong on an EV because it doesn't use those parts in the first place. The only thing in the prior list that can even be done on an EV is brake servicing. Luckily, regenerative braking is so strong in a full EV that it can pull you to a dead stop going down a steep mountain road. This means that the regular old friction brakes in an EV are hardly ever used (though they should be engaged every once in a while just to clean the rotors). There are other maintenance items that still exist for EVs, like replacing the 12 V battery (it's used to safely engage/disengage the high power battery) and fixing structural things like cracked windshields, axles, and PV boots. That being said I spent nearly $1,000 a year on maintenance for an old Versa I had but I've spent $0 so far on my Bolt and expect to average well under $100/year on maintenance for it, mostly for tires. This $900 annual savings is far more than the $100 I saved on fuel this year, and will likely be greater even after I start driving more miles again post COVID.

Saving the World With an EV

If you've been following along so far, you've gathered that an EV can be both fun and cheap, but how does it affect the planet? Honestly there is a ton of disinformation out there about this right now. People love to complain about the Cobalt used in EV batteries, but only about 10% of the cobalt that is mined each year is used by them. That cobalt is dang expensive so automakers are working to reduce it. Tesla actually plans to eliminate all cobalt use in their next generation of batteries. The child labor that has gone into mining cobalt for decades is horrendous, but most of the people bringing it up now have probably never once complained about cobalt being used to desulferize gasoline. This is because the roots of these complaints are funded by the fossil fuel industry. The millions of dollars they put behind these claims means that they get repeated and repeated till suddenly they're at the top of mind for everyone, even though they don't include a full view of the harms of fossil fuels

A similar campaign has been waged against lithium, claiming that its extraction is terrible so EVs are terrible. The reality is, that mining anything isn't great, but when comparing mining of lithium to oil extraction, the environmental cost is not close. There have been no lithium spills that have fouled entire coastlines, but the list of such oil spills is long. When you put lithium into a battery it can be used for hundreds of charges, and then eventually recycled. When you put gas in a car it gets burned once and then its exhaust warms our planet. As more EVs get built and battery tech develops lithium use in them may even be reduced or replaced by a switch to solid state batteries or some other technology. There are lots of ways to make energy dense batteries, so even if a single element becomes hard to get safely there are alternatives. Rather than trying to stall adoption of EVs because of specific mining problems, we should work to fix those problems and accept the affects of this on EV price.

Once past the disingenuous mining critiques and disinformation on climate change the question becomes "How fast do we need to switch to EVs to avoid catastrophic climate change?" Luckily there's a wealth of good research on this topic. The rate depends on how fast we switch our grid to clean renewable energy. Decarbonizing our grid faster allows us to switch to EVs more slowly because each EV saves us more. Even if we have 100% zero carbon electricity by 2050 we'd still need to replace 67-84% of our cars with EVs by then our current amount of driving (67% gets us to 80% carbon reduction, 84% gets us to 90%). If we only cut our current electricity generation emissions amounts by 75%, down to around 100 grams of CO2 per kWh then we'd need over 90% of our cars to be EVs by 2050.

Cars last a long time, so to reach 100% of our cars being EVs by 2050 we'd need 100% of new car sales to be EVs by 2020! Of course that hasn't happened. There is still the possibility that our gov could pass a cash for clunkers type program to phase out gas cars more quickly down the road, but who knows. We can and should also support bikes and transit to reduce miles driven. Still, the basic reality is that we need to be switching to EVs much faster than we currently are to hit our climate goals. You can go read the full paper on this if you want the nitty gritty. The brass tacks are that if you care about this planet, or even just humanity's future on it, locking in emissions reductions from switching to electric vehicles and reducing miles driven matter far more than the environmental impacts of lithium and cobalt extraction.

To really understand the impact of an electric car vs a gas car, you need to do a full life cycle analysis (LCA). An LCA sums up all the energy that goes into both building and using a vehicle over its lifetime. The Union of Concerned Scientists did an EV LCA in 2015 and has been providing regular updates over the years. Their latest update finds that the most efficient electric car (the Tesla 3) beats all gas cars in real world MPG in almost every state in the union. The 3 only gets 49 MPGe in Oahu because the power generation mix there is so dirty. On the other hand it gets a whopping 306 MPGe in upstate New York home of a ton of clean hydro-electric power. If you average the power generation mix across the entire USA in 2018 a 3 would get 116 MPGe. Given the incredibly low cost of renewable generation our grid is getting cleaner every year, so this will continue to improve, while a gas car's MPG will stay the same. If they guys at Aptera actually turn their amazing prototype into reality it will be more than triple the Tesla 3's MPGe and handily beat gas cars everywhere on the planet.

eBikes: The Actual Best EVs

Of course if you really care about the environment and your wallet, there is one way to travel that’s even more efficient than an electric car, and that of course is an electric bike. As I have detailed before, eBikes get between 1,000 and 3,000 MPGe, and that’s about 10-30 times better than an electric car. If you want to really walk the walk on efficiency, you should be riding one of these amazing machines for all short trips. Riding an eBike 100+ miles to visit family is a difficult feat though, and that’s where electric cars can really shine. Even our most efficient mass transit, a Greyhound Bus, only gets around 150 MPG per person. My Bolt gets 110 MPGe on the highway, so with 2 people it’s getting 220 MPGe per person and with my whole family of 4 it’s at 440 MPGe per person. Electric buses and trains may be able to beat this (this whacky 40,000 MPGe train type thing certainly does), but its nearly impossible to find them. For the time being, an electric car is the most efficient form of long distance travel. If you really want to save money eBike a bunch and rent an electric car the few times you actually need to. If you’re not quite ready for that, and still not sold on getting a full electric car then buy a used gas car that’ll last 3-5 years and die just as used electric cars get ridiculously cheap. To profit greenly, never buy another new gas car as long as you live.

Here at Profit Greenly, I mostly talk about the dollars and cents underlying green choices. Biking is one of the most profitable green choices you can make and in this post I delve into how it can make you feel better and more alive. If you're apprehensive about getting things done with a bike, don't worry about it, we all were at some point. Hopefully exploring my life experience transitioning from driving to cycling will give you some thoughts on how to get your own biking joy and profit greenly.

Early Life Biking

I did not have an ideal introduction to biking as a kid. Starting late, I didn't learn till I was 8 years old. I was scared to go down steep hills fast, but I could ride over to my friends' houses a few blocks away. My parents both worked so my brother and I walked to and from school each day. This was about a mile each way so once I got more comfortable enough to bike it it saved me a ton of time. Beyond time savings the feeling of biking as a kid was just biking joy. The freedom to get anywhere in the neighborhood was truly liberating. When I think of my own kids growing up and biking like this I get a bit apprehensive because car danger feels like its increased, but back then I never remember having a close call with a moving car. My biggest accident happened with a parked car actually. One day I foolishly tried to ride to school during a torrential rain storm and ended up crashing into the back of one! I broke my front teeth on the back window, but didn't let that stop me from biking again. Sometimes I wonder what the owner of the car thought when he found two tiny pieces of teeth embedded in his back window though.

My only other big childhood biking issue involved more psychological trauma than physical. I was given a sweet new mountain bike for my 12th birthday but it was stolen from our carport literally the day afterwards, along with my brother's bike. Luckily, my parents got us new ones, but the experience left me paranoid enough to develop my own DIY bike GPS tracker later in life. I kept riding after this to school, to soccer practice, and around town until I started going to a middle school that was 4 miles from my house. At that point my parents were divorced and I'd occasionally ride between my Mom's and my Dad's. My memory told me that this trip was shorter than the one to my school, but looking at the map now I can see it was actually a half mile longer. It must have felt shorter because it was along quiet neighborhood streets and through a large park while the route to school was along a noisy and dangerous road filled with car traffic. I didn't realize it at the time, but this was my first experience with just how important safe cycling infrastructure is.

College Biking Doldrums

The bike I'd been given at 12 came to college with me and I used it a bit as a freshman (my parents had smartly bought me a full size model at 12 even though I could barely fit it at the time). Unfortunately, the route to campus from my dorm required a trip down an extremely steep hill that t-boned into a busy street. When the roads started to ice over I got scared of sliding to my death in this intersection and switched to walking instead (if only I'd known about winter bike tires). After that my bike spent the better part of 4 years rusting at various outdoor bike parking areas around campus, only to be harvested in a campus wide junk bike removal the week before I graduated. The really unfortunate thing was that during the summer of my sophomore year I got my dream summer job at Autodesk and rather than using this bike I stupidly bought a car to commute to it. Looking back on this with the wisdom of age I can safely say that this was a multi-thousand dollar mistake. The commute to my work was under 4 miles from where I lived and the office building had a shower in it. I could have even picked a summer sublet that was closer to the office, but that I wasn't advanced enough for that sort of life optimization at 20. Having the car did enable me to take a few long drives back home to visit my family and friends over my college years, but I could have paid for fancy plane tickets for those trips instead of driving with all the money I'd have saved by not owning a car. Live and learn I guess.

Mid 20's Return to Biking

In my mid 20's I really started getting back into biking and rediscovered the biking joy of my youth. I bought a used 1960's Fuji 10 speed and started riding it around on bike paths with my friends. Eventually I got comfortable enough with it to start riding to work. This was a nearly 17 mile ride, but I was young and strong and it was mostly on the nice and safe W & OD bike trail. The ride itself was a beautiful, calming hour and a half of good exercise that let me think about things before I got to the busy office and left me feeling energized for the day. My office had shower and a deal with a dry cleaner who would pick up and return right from the office so my suits just lived there and I was the cleanest person at work despite getting sweaty every day. On top of all this there was a train/bus route between my home and my work that let me leave my bike if the weather turned bad or I was feeling too tired for the ride home. This sort of safe and useful infrastructure is not common in America, but it could be and if it were how many more people would bike to work?

As I got into my later 20s I started to upgrade my biking gear and knowledge. First, I bought a speedy Lemond road bike that cut a full 1/2 hour off my ride to work compared to my old Fuji. Then, I learned how to keep my bikes running well for almost no money by going to The Bike House bike Co-Op in DC and volunteering with Bikes for the World. A couple years later I found a 1989 Cannondale touring bike for $300 and put a rear rack and panniers on it so I could haul loads of groceries, recycling or library books. To handle truly huge loads I DIY'ed a used bike trailer into a cargo hauler. I learned about all the other trails and safe biking streets in my area and found ways to get not just to work, but to the houses of my family and friends. To enable riding in the cold of winder I got bright lights, wool socks, thick gloves, a good coat, long underwear and a realization that with the right clothes no weather is too cold. The lights also allowed me to ride my bike to late night parties and shows. I was starting to realize that a bike could get me almost everywhere I needed to go and all of this biking kept me in great physical shape. As I slid into my 30s and my friends became pudgy with age while I stayed the same weight I'd been in college. More important than that though was the great feeling of accomplishment I got everywhere I went by bike. I wasn't just lazily hopping in my car to get where I needed to be, I powered myself there with my own muscles, really experiencing the world and using my strength to accomplish meaningful stuff. It was amazing.

Fatherhood and Family Biking

Many people think that you can't bike with small children, but as I got older and became a dad my biking actually increased. Part of this was because I was reading Mr. Money Mustache's many opuses on biking (here, here, here, here, here, here, and here) and part of this was because shortly after my first kid was born I moved to Tempe AZ, one of the most bike-able cities in the whole US (not the most bike friendly in terms of car policy, but the lack of rain, flat topography and tons of bike paths make it super bike-able). My family actually lived there car free for our entire first year. Then, when my wife was pregnant with our 2nd kid she demanded we buy a car so we wouldn't have to take an Uber to the hospital when the baby was coming. I had joked with her that I should buy a pedicab instead and take her there with that, but the siren song of the automobile still called to us. Looking back with 20-20 vision though with the hospital only 1/2 mile from our house and even with a new pedicab costing $5k, that's still thousands less than we spent on our used car with next to no maintenance, registration, or insurance fees. My wife's office was also far from any streets/parking lots so a pedicab would have allowed me to drop her right at the building door when she was very pregnant, something I couldn't do with our car. Ah well, live and learn, maybe one of you readers will pedicab your wife to deliver a baby? If you do I will be truly excited to hear what happens when it's all done and the nurse comes out to inspect how well you have secured your new baby's car seat.

Now that my kids are a bit older I've tried out nearly every way to transport them by bike (check out my comparison review of these options). Riding my kids to and from school in our cargo bike gives me my recommended 30 minutes of daily exercise and I feel refreshed and energized afterwards. My kids get to experience nature, play I-spy and wave at people from the back of the bike. My hope is that this will better equip them to deal with the real world. While other kids are being trained that every trip must be made in a climate controlled car, they're actually getting out in the elements. When it's below freezing outside and they ask me to remove the bike cover though I wonder if maybe they're becoming too hardcore? We do have a car now too, and we use it for long trips and bad weather. If our town had access to a good rail line and actually plowed snow out of the bike lanes in winter we might not need it, but those are dreams for the future. Still, even though I do enjoy the instant power of our Bolt EV, it does not bring me the same joy as riding my bike. Even running my wife's eBike on pure throttle is just more fun than driving, there's just something about being out in the open air on two wheels that's life affirming (plus her eBike gets 1,250 MPGe vs the Bolt's 128). It's like JFK said "Nothing compares to the simple pleasure of riding a bike."

Useful biking is one of the most important ways to profit greenly. It saves money, cuts pollution, and improves fitness and happiness. When kids enter the picture though biking as transport becomes more challenging. Even if you get past the initial fear of traffic, you're confronted with a myriad of ways to get your kids around by bike with wildly varying price points. Over the past 4 years I've managed to try most every type of kid hauling bike contraption and extensively researched the rest. In this post I'll reflect on my experiences to help other parents who are trying to figure out the best way to profit greenly by hauling their kids around by bike.

Front Handlebar Seat

The first way I carried a kid on a bike was with a $70 Bobike Mini front seat mounted on my handlebars. My main bike has mustache bars that keep my hands fairly wide and high so this worked great (narrow/low drop bars wouldn't work so well). I was a bit nervous putting my son in for the very first time, holding the handlebars with a death grip as my wife strapped him into the seat. Once he was in though the ride was really nice, and over years of riding with both him and later my daughter in this seat I never once came close to falling with it. This got me comfortable enough to not grasp the bike super tight whenever putting a kid in/out of the seat and I loved it.

The best part of a front seat is how your kid can see everything so clearly while riding with you. Both of my kids absolutely loved being in this seat and had plenty of laughs while riding with me. Because they're right there between your arms you can see what they're doing, talk with them, even give them a little hug with your elbows. Other road users see them too, which results in a lot of waves and smiles from passers by.

The most common annoyance with this seat was that I had to splay my knees a tiny bit to keep from knocking the back of it. Once I got used to riding like this it wasn't too big of a deal, but it must be far worse with those seats that mount over the top tube of the bike and I wouldn't recommend them. The other issue that came up when I started riding with my daughter in this seat is that she could actually reach down and adjust my bar end shifters while riding, putting me into a different gear! My son never did this, but my daughter thought it was hilarious. We eventually came to an understanding about it, but it was a surprise drawback to a front mounted seat that I didn't experience the first couple years I rode with it with my son. The biggest issue with front seats is that kids outgrow them pretty fast. My seat claimed to work till 3 years, but both my kids legs got too long for it just past 2 (me and my wife being over 6 feet may have contributed to this). Still, $70 for a ton of fun over 2 years seems like a good deal, and a great cheap way to test the waters on biking with your kid.

Bike Trailer

After the front seat, the next kid carrying contraption I tried was a bike trailer. I was riding with my son in the hot, desert environment of Tempe Arizona and I got afraid that on longer, hotter trips he might get too much sun in the front seat. My solution to this was to buy a used Trek GoBug trailer (now discontinued). This trailer had a built in sun shade and I also threw one of those little misting fans in the back to keep him cool. The trailer worked great for longer rides, but I still used the Bobike front seat for short trips because it was so much smaller and easier to maneuver with. The trailer did allow me to bring a bunch more stuff though, so it was great for taking trips to the pool or park with a bunch of toys, or even small kid bikes. Many people criticize trailers as not being visible enough to cars, but this was never an issue for us. We were lucky to be riding almost exclusively in bike lanes/paths though, because while Phoenix drivers aren't the most bike friendly, the bike infrastructure there is pretty great (we've also had no visibility issues with it in State College).

The particular trailer I bought also had the ability to turn into a jogging stroller, which seemed like a great feature but was executed poorly. The main issue was that the front wheel + supports were huge. They'd fill up nearly the entire trunk of the trailer, and when you put them on (which took like 5 minutes of fiddling) they'd make the trailer over 6 feet long. The front wheel was also fixed so turning this beast meant that you'd have to pop a wheelie. I biked it to a mall once with hopes of pushing my son around inside, and while I managed getting around it was so bad that I quietly declared "never again". If I was going to do it all over again I'd get a trailer with those fold down caster wheels like the Thule Chariot. Of course that trailer costs like $1,000 while mine was under $100 used, but I bet if you looked hard you can find a deal on a trailer with fold down caster wheels.

The other great feature of the trailer I bought was that it had 2 seats. That meant when my daughter came along there was room enough for both her and her brother. I even used its stroller feature to push them around town before her neck was strong enough to be pulled along in the trailer by a bike. I biked them both around in this for a little over a year, but then the kids started growing bigger. At 1 and 3 they could physically still fit in the trailer, but they were smushed up against each other (especially with winter coats on) and started fighting a lot. Getting 6 months older just made it even worse. I wish someone made a kids bike trailer with more room and a higher weight capacity, but it just doesn't exist. This eventually led me to my next child bike purchase, a tag along bike trailer.

Tag Along Trailer (aka tadpole)

I bought a tag along bike trailer to keep my kids more separated on rides and give my son more experience pedaling. The WeeRide Co-Pilot used to be just $75 on Amazon (now the price is up to $110, probably thanks to a global pandemic that has spurred a surge in biking). At 4 years old he barely fit on it, and I had to turn the handlebars around backwards to bring them a bit closer to his body, but he totally loved it. The feeling of helping pedal really brings him joy, and I think it helped him transition from his balance bike to a real pedal bike too. His balance bike experience also let me trust that he'd actually hold on to this tag along and not just fall off in the road randomly. With my daughter in the front handlebar seat this setup let me carry both kids around in one long bike train type setup (though parking and getting them out took a bit of balance).

The main issue with the tadpole I bought was how it connects to my seatpost. There's a connector piece of metal with 4 bolts that you tighten it around the seat post. The connector on the tag along slides into this and a quick release bolt goes through a side hole to secure it. This is easy enough to do, but the cheap model I had didn't have the side holes lined up perfectly. I'd shove the metal connecter all the way in and then have to slowly work it back (the fit is tight so it doesn't easily slide) to line up the holes and put the quick release clamp through. I figure a more expensive model wouldn't have this issue, but I solved it by cutting a wood spacer to the right size and taping it inside the connector on my seatpost. The other issue is that even though there's an articulating joint behind the connector it doesn't bend very far. Too tight a turn can torque the connector on your seat post to a new angle and it's annoying to turn it back. This happens even if I screw the bolts down super tight with an impact driver, and just seems like an issue with how this type of connector attaches.

A vast improvement on the cheap tadpole I bought is a more expensive model called the Weehoo. I'd originally considered buying this one, but decided against it as too expensive, then a few months ago a friend randomly gave us one that her kids had outgrown and it's been amazing. It has a metal cylinder that goes around the bike's whole seat post which totally avoids the problems I mentioned above. There's a black nylon bushing in this that lets it fit snugly on different size posts and rotate around freely as you turn. If you want to get really aggressive you can actually turn the bike over 90 degrees and ride a circle around the Weehoo pivoting it on it's tire. The Weehoo's recumbent sitting position is also an improvement as it allows you to strap the kids in. This means that I'm comfortable putting my wiggly 2 year old daughter back there when I would never be okay putting her on our more bike like tag along. The Weehoo we got is a tandem model too, so you can put both kids in it. It's even got its own little panniers, along with pockets on the sides of the seats for water/snacks and seat back pockets for toys. The long bike chain is enclosed in plastic to keep your kids safe and clean. Heck, they even sell little sunshades and weather enclosures for this thing, it's got it all!

The Weehoo is nearly perfect with only a couple small flaws. First, it's fairly unstable getting the kids in/out of it. This could be improved by adding a big double kickstand to the bike, or a 2nd kickstand on the Weehoo. Next, only the kid at the front can pedal so sometimes there can be fights over who gets to sit there (also the pedal straps there don't work great). Most importantly though there's not a ton of room for two longer legged kids on it. I expect my kids won't be able to both fit on the Weehoo anymore when they're 4 and 6, maybe even earlier. The good thing is that you can still hold one kid by just pushing the front seat further back and relegating the back seat to storage. I could see it lasting a single kid till 8 or older this way. This bike trailer has become my kids' favorite way of getting around so I can certainly see doing this, but I'd need my wife with me to pull kid 2 on the tag along. The need to be able to haul 2 big kids around is the same dilema I was confronting before we were given the Weehoo as my daughter outgrew her front seat, and is why I bought my cargo bike.

Cargo Bike

Rather than spending $500 on a Weehoo that my kids might outgrow in a few years I decided to spend $1700 on a used Madsen bucket bike which I hoped would last much longer. That was a bit over a year ago and looking back I'm mostly happy with my purchase. The great thing about the Madsen is that it can carry a ton. It has seating for 4 in the bucket and maxes out at 600 lbs of cargo. The most I've hauled with it was 500 lbs (car batteries, cinder blocks and me). This had me really wishing for e-assist, but the Madsen frame handled it no problem. I've thrown my wife and kids in the bucket at the same time for a short ride, but would not recommend that in general. The bucket on the back is also nice because the kids like to wave at the cars coming up on us. This is fun for them and seems to lead to less aggressive drivers.

One of my main concerns before buying the Madsen was whether it would be stable to carry so much weight on 2 wheels. After 1 year of riding I can say it definitely is. I'd originally been thinking of a cargo trike like the Virtue School Bus, but after test riding one and feeling how a trike tilts on uneven ground I decided it wouldn't work for me. The Madsen has been able to handle the uneven bike paths of my town with aplomb and even though it's big it's narrow enough for another bike to pass it without off-roading. It can also handle fast speeds a lot better than a trike too. The trike I tested felt super wobbly at 15 mph and would need to be even slower to turn a corner. The Madsen turns fine no matter how fast it's going and while its gearing maxes out around 20 mph but I've gotten near 30 on downhills with no issues (FYI: I do brake to keep it slower when my kids are in it for safety). Conversely on steep uphills I can go into the lowest gear and spin along around 3 mph just fine. This is just barely faster than walking, but you more than make up for this on the flats and downhills (and if time is really an issue you can get e-assist to speed you up). A trike would be more stable at this super low speed, but it'd take even more strength to get up a hill. The real only balance issues I've had are when my 2 year old leans hard from one side to the other to look at something, but this hasn't tipped us yet and I don't think it will.

The seating for 4 does give my kids more room to spread out, but at 2 and 4 they still fight sometimes. When this gets bad I wish I'd bought a bike with the cargo bucket in front of me (called a bakfiets), so I can see what the kids are doing. I had a similar feeling when my daughter threw not 1, but 2 water bottles out into the street to be flattened by cars. But, the buckets on most bakfiets are much smaller than on my Madsen so I wonder if that'd just lead to even more fighting? The other issue is that most bakfiets cost a lot more than my Madsen. An Urban Arrow can cost over $5k and a top of the line, fully loaded Riese and Muller Load 75 can cost over $10k. You can get a used Leaf for less! Obviously there are advantages to a bike that an electric car doesn't have like fitness, offroading, and ease of parking. Both of these premium bakfiets also have electric assist motors, and their flat cargo areas can hold some items that the Madsen can't, but the price is a huge difference and for me it just wasn't worth it (they're still cheaper than most SUVs though). Even if I add e-assist to my Madsen it'll be 1/2 to 1/4 the price of these bikes. And e-assist is definitely something to be considered. As I've written before an eBike can give you well over 1,000 MPGe and it will make a heavy cargo bike much easier for people who aren't athletes/masochists.

The hump in the Madsen bucket doesn't have to be wasted space either. I was able to mount my DIY GPS tracker and the battery pack for my LED bucket lights in the empty space under this hump (turns out an old takeout food container fits perfectly in the frame down there). This keeps these parts safe from both thieves and rain in a way that few other bikes can duplicate. The wheel lock of the Madsen along with its huge size and my GPS tracker means that I am comfortable just parking it anywhere which really adds to its ease of use. I can just roll right up next to the front door of any building and lock up the Madsen with no searching around for a bike rack that might not even exist.

One of my grand visions for the Madsen was that I'd use it to ferry other kids to and from school, playdates, etc., like a sustainable mini-van. Unfortunately Covid has put this dream on hold, but if it weren't for that I think this is something the Madsen can do that many smaller cargo bikes can't. Another great feature of this bike is the weather cover. I rode it to school pretty much every day last winter when there wasn't snow in the bike lanes (unfortunately, my town loves to plow snow into bike lanes) and the kids were never cold. Honestly, my kids are weird ice children who'd often request that the cover to lowered even when it was freezing out. With the cover up they're protected from the wind and the bucket warms up 5-10 F above the outside air. I even throw some blankets back there, but like I said my kids are strange ice beasts so they didn't use them much. The cover also keeps the kids dry in the rain, and shaded on sunny days (this is where its unzippable windows really shine). My only wishes for the cover are that it was easier to zip up the little black cover that goes over it when not in use, and that there was a clip to truly lock it in place when it's up. You pull a strap tight to hold the bottom of it down to the bucket, but there have been a few times when this has failed and the whole cover has flapped open while riding. Luckily this hasn't hurt anyone injuries, but it's definitely scary (I'm thinking of screwing 2 loops of metal into the bucket that carabiners can clip onto to prevent this).

In terms of negatives, the main issue with the Madsen is its weight. This thing weighs like 90 lbs empty, that's far more then 50-60 lbs of my touring bike and Weehoo combo. And while the Madsen carries that weight well, you definitely feel it. When I first got it I stopped doing weight lifting for a month or so because all my body could handle was adjusting to pedaling this giant thing around. I'm sure an e-assist would make this a non-issue but I'm focused on saving money/getting stronger right now. The other question is how long this bike will really be useful for my kids. It has the weight capacity to keep hauling them till they're teens, but how long will they really accept being ridden around in it? At 4 my son is already very proficient on his own bike and my daughter's going strong on her balance bike. Will they refuse the bucket at 6 and 8, what about 10 and 12? I think only time will tell on this, but my fingers are crossed.

If I had to do it all over again what would I buy?

Madsen purchase delay gain
$1700 Used Madsen Cost
 - 6.24% 2018 SP500 ROI
= $1593.92 total in 2018
 + 28.88% 2019 SP500 ROI
= $2054 total in 2019
 - 15% capital gains tax
= $301 gain
 - $70 Bobike front seat
 - $100 used GoBug
 - $70 WeeRide Tag Along
= $61 gain from delaying Madsen purchase 2 years

So, having experienced all these different ways of transporting kids around what would I recommend to new parents just getting started? A common school of thought is that since a cargo bike can do everything you're better off just buying it first. My main recommendation is the opposite though, start cheap and go from there. The reason for this is that I factor in lost investment income/interest costs. The front seat, used trailer and tag along trailer I got were all tons of fun, very useful and essentially free. This is because keeping the $1700 I paid for the Madsen invested for 2 more years earned over $300 which is more than all of these things cost combined. Yes one of those years saw high stock gains, but even a lower 7% ROI would have paid for them and that isn't even factoring in resale price (I'm probably giving all my kid bike stuff away when done).

Hindsight makes the optimal spending path for getting my kids around quite clear now. The cheapest choice would have been to only buy a used Weehoo and nothing else. This would have let me bike my kids around from a very young age through today for just a few hundred bucks (I could have spent another hundred or so on shades/weather covers). But, starting out I had no idea how much my kids would love the Weehoo, how quickly they'd outgrow the front seat and trailer, or how COVID would prevent me from bringing their friends along in the Madsen. I'm still happy to have had time with my kids on the front seat, and the GoBug as a tandem stroller was useful when my daughter was too young to be on a bike. My big fat cargo bike is also still my favorite way to ride them around. Its huge storage capacity and the security of the wheel lock and DIY GPS on it are just awesome. I've also run a few trips with it that none of my other bikes could handle (though a Surly Bill or Bikes at Work trailer could handle such loads for less). In the end I hope this opens your eyes up to all the possible options for carrying your kids around and lets you realize that while you can spend a lot of money doing so you don't have to. Whatever you do though, don't forget that even a fancy cargo bike is far cheaper than the vast majority of cars. Biking your kids around will likely make you fitter, happier, and wealthier, the sooner you start doing it the sooner you too can profit greenly.

The first question people usually ask after learning that I have solar panels on my roof is whether I bought a battery backup system as well. This makes sense from a basic off grid viewpoint, but not so much in the real world. Most electrical grids have such low levels of renewable generation right now that they can easily act like huge batteries for the small numbers of people who get solar roofs. For grids like this installing individual battery systems is a waste of resources. In this post I'll try delve into why most solar homes don't need their own energy storage yet and how this will change in the future.

2021 Update: Strong demand for Powerwall’s has made Tesla increase their price yet again. They’re now $7500, and there’s another $1,000 for a “Gateway” that controls it and a crazy $3500 installation cost (I have to imagine you could cut this by DIYing, or just hiring a good local electrician). This makes the Powerwall ROI worse, but hopefully eventually supply will catch up and prices will fall the way the raw price of lithium ion batteries has been falling.

https://electrek.co/2021/01/17/tesla-increases-price-powerwall/

Why do You Need a Battery?

A battery can absorb excess solar power when the sun is shining brightly and give it back when it isn't. The most common use case for this happens when the sun sets every night. The size of a battery needed to handle each evening depends on the season and location. A long, cold winter night at my house in PA can draw over 40 kWh of power while a short temperate summer night here can draw less than 5 kWh. If I was in Arizona running the AC on summer nights and very little heat in winter this would be quite different. In Pennsylvania my winter draw is amplified because I use a high efficiency heat pump that runs on electricity. If I heated with another fuel, or had a better insulated house these numbers could be much lower, if I heated with old school resistance electric heat they could be much higher.

Another source of intermittency is clouds that pass by and reduce generation during the day, or sometimes for days on end. For example, there was a cloudy stretch of nearly 3 days last October where my solar generation was consistently below my home's consumption. My house drew nearly 60 more kWh than my panels generated during this period. Smaller passing clouds require a far smaller battery system to handle, often under 5 kWh. The big question is what percentage of solar generation a house can actually use over the course of an entire year. Here's a graph that shows this for my house at different battery sizes.

As you can see with no battery only 27% of the power my panels generate is actually used by my house. The rest goes back to the grid for my neighbors to use. If I add a tiny 6.75 kWh battery this jumps to 42% and a 13.5 kWh pack takes it past 50%. As the pack size keeps increasing though the percentage of self use starts tapering off and the big red grid draw bar stays pretty flat. This is because of the biggest intermittency gap cause, Winter.

With the shorter days from November through February my panels generated about 1,800 kWh while my home consumed about 5,000 kWh. This 3,200 kWh difference is about equal to the excess solar production my home produces during the rest of the year. To go off grid I would need a way to store this huge power difference. As you can see in the above graph the solar use percentage starts leveling off at higher battery sizes. The reason for this is that the extra kWhs added would only charge and discharge a couple times a year. Battery capacity from 70 kWh to 3200 kWh for my home would only charged and discharged once per year. This is not an efficient way to use a battery that costs a lot and is capable of thousands of charge cycles so expanding to that size would be foolish.

Does a Powerwall Make Sense?

The most common form of home energy storage today comes from Lithium-ion (Li-ion) batteries. For just $7050 you can buy a 13.5 kWh Tesla Powerwall 2 made with this tech. As you can see in the above graph that would increase my self usage to 51%, but the weird thing is that it would save me $0. This is because in PA I have net metering which means that I get to use the kWhs I generate to offset the kWhs I consume no matter when I generate them. If my state didn't have net metering then I would have more incentive to add a battery.

Another way to accomplish this is through time of use rates (also called TOU rates) that charge different amounts for a kWh based on the time of day it is consumed. Electricity production costs change throughout the day based on supply and demand, so a TOU rate can charge customers more fairly based on their usage patterns. But they also confuse a lot of customers and there are still lots of utilities that just charge a single flat rate per kWh no matter when it is consumed.

California utilities have truly embraced TOU rates and have some with huge peak price changes. The TOU-D-PRIME rate from SCE adds 26 cents for each kWh used between 4 and 9 pm in summer. A Powerwall 2 is warrantied to provide around 37,800 kWh of total discharge over its life or 18.6 cents/kWh if sold for $7,050. On this rate plan every kWh the Powerwall lets you shift out of this peak is profit. Of course to get an exact ROI you have to factor in prices during weekends and winter, and how many kWh of use the battery will really shift each year. In the end though if you're on this rate it's likely that a battery will have a higher ROI than bonds.

The battery backup provides even more value by keeping a home powered during blackouts. These are now happening more often in CA due to wild fire issues. If a battery backup avoids the need to install and fuel a backup gas generator, along with this peak price avoidance then its ROI could be really impressive. With battery prices continually trending downwards home based batteries may become one of the best possible investments in California in the near future.

To truly optimize ROI on the above rate the Powerwall would stop feeding energy back into the grid after 9 pm. This still means that your home would be drawing power from the grid at night. Looking into why a utility would incentivize people to keep drawing power late at night shows why most home owners still don't need batteries right now.

When Does A Grid's Energy Mix Requires Batteries

To understand when batteries are needed for a grid you need to look into how much power different energy sources provide to that grid throughout the day. Luckily the EIA provides a handy web tool that does just this for pretty much anywhere in America. This tool lets you drill down to your particular grid and see daily and even hourly electricity generation by source. Here's hourly generation by source for my grid in Pennsylvania (PJM) on April 27.

As you can see on the above graph my grid has a pitifully low amount of solar generation. Our wind gen is low too, but its high enough to at least be visible. When the wind picks up you see the green area thickening and the brown Coal and Natural Gas areas contracting. These plants are being fed less fuel similar to how utilities have reduced generation during times of lower demand for decades. This shows how initial deployments of renewable generation displace fossil generation without any battery storage. This does require the utility to predict of how much renewable generation there will be at a given time, but they're are actually pretty dang good at this. As they gain more experience and have renewable generation sites across a larger area their predictions will only improve.

There are also grids that have installed such a high percentage of renewable generation that battery storage could help them reduce costs and emissions even further. California's grid (CISO) is an example of this, with a far higher percentage of renewable generation than PJM. In this graph you can see how gas usage only peaks up at the end of the day when the sun goes down but demand is still high. This is also the time of day the CA TOU rate I discussed above charges extra for, which makes sense because gas generation has fuel and personnel costs that renewables simply don't.

This graph also shows how gas generation in CISO currently has a bit of a floor. There's a period around noon when CISOs total energy generation can be above their total demand, but their gas plants consumption doesn't go to zero, it's just as high as it was at 5 am before the sun came up. This is because a lot of gas generators can take hours, or even days to start back up after being shut off. Operators who expect their plants to be needed sooner than that leave them on at their lowest consumption mode instead of turning them off entirely so they can quickly ramp back up to meet the demand that they know is coming. When there's enough battery storage or fast starting gas plants to meet the demand that these gas plants are starting back up for then the gas floor can drop as the plants that can't start up fast get truly shut down for longer periods of time, and eventually forever. This is part of the reason why CA utilities are starting to contract for some truly huge battery storage.

More Solutions than Just Batteries

Of course batteries aren't the only way to solve the intermittency problem for renewable generation. Excess renewable energy can be stored by pumping a bunch of extra water up behind dams, or creating green hydrogen. Vertically mounted bifacial solar panels can generate more at dawn and dusk. Wind can be mixed with solar with the understanding that there are many times when the wind is blowing, but the sun is down and vice versa. This is particularly true if you build efficient long distance transmission so localized weather conditions matter even less. Another option is to simply massively overbuild renewables so that they produce what you need when conditions are bad, and you simply turn some of them off when conditions are good. Given the falling prices of batteries though, they just may continue to be the best solution, particularly if we ensure that the coming EV transition includes vehicle to grid (V2G) discharge capability and EV battery life further improves.

The reality is that most of these options will be implemented by utilities at the grid level. If we want homeowners with solar panels to buy their own batteries then we'll need to change how we charge them for power. Time of use rates with aggressive peak pricing like in California are a great way to do this, but to be fair they need to be applied to all utility customers, not just those with solar panels. In most of the U.S. right now the most profitable choice is to simply install solar without a battery. Given the extremely low percentage of renewable generation in many U.S. grids, like PJM, this is probably the right solution for the time being. Hopefully someday in the near future all of our grids will have enough renewable generation that storing excess green electricity an important consideration everywhere.

We're in the midst of a quiet transportation revolution right now. Recent advances in electric motors and batteries have made electric cars a reality and they're getting cheaper and better every day. A lot of people have noticed this, but electric bicycles (eBikes) haven't gotten nearly as much attention. These machines are so efficient they can have lower emissions per mile than walking or pedaling a regular bike. Back to the Future II promised us hoverboards by 2015. Instead, we got eBikes that get over 1,000 MPGe and save us thousands more dollars than they cost. Maybe the future's not so bad?

Our 1,000 MPGe Reality

People can get pretty impressed when they read that a Tesla can get the equivalent of 140 miles per gallon of gas (MPGe). This makes sense because we've become accustomed to terribly inefficient gas cars that get 30 MPG or worse. Once you do realize that eBikes easily get over 1,000 MPGe, even an EV will seem downright inefficient. Let me take a moment and do some math to show the insane MPGe of eBikes (feel free to skip to the next heading if you hate numbers and just want to take my word for it).

Math Time!

MPGe Math
48V * 14Ah
   = 672 Wh
672Wh / 1000
   = 0.672 kWh
0.672kWh / 33.7 kWh/gal
   = 0.02 gallons
25 miles/0.02 gallons
   = 1,250 MPGe

The Radrover eBike is one of the better selling eBikes in America and yet most people have never heard of it. It has a 48 Volt (V) 14 amp hour (Ah) battery pack. These numbers mean that its battery holds 0.672 kilowatt hours (kWh) total energy. The EPA estimates that 1 gallon of gas is equivalent to 33.7 kWh so this battery has the equivalent energy of about 0.02 gallons of gas. That's about 2.5 fluid ounces, which would be the tiniest gas tank ever! This miniscule amount of energy propels the bike 25-45 miles on a full charge depending on how much you pedal.

Lets assume no pedaling so the bike is 100% powered by its electric motor. This gives it the low end of 25 miles of range per charge. Divide 25 miles by the 0.02 gallons of gas equivalent of the battery and you get an insane 1,250 MPGe for this bike. And this is for a nearly 70 lb eBike with super fat off road tires. A much smaller GoCycle Gx can go 25 miles using just a 0.3 kWh battery pack giving it nearly 3,000 MPGe! No car can come close.

Still Room to Improve

We're still just at the beginning of the eBike revolution. There's a lot of room left to improve their motors, batteries and the electronics that control them. The improvements to this tech that are being spurred by electric cars should trickle down to eBikes eventually. I expect in a decade or so we'll see lots of eBikes weighing under 30 lbs which will make them easier to handle and even more efficient.

The electricity that fills their batteries is also getting cleaner with renewables starting to replace fossil fuels in much of the world. In upstate NY, home of the lowest emissions per kWh in the U.S., a Radrover produces the same emissions as a gas car getting over 2,700 MPG and a GoCycle is over 5,000! To put this in perspective, just one solar panel on my roof generates enough electricity to propel a Radrover nearly 15,000 miles each year.

Emissions are low even when charging from the grid in the place that produces the most emissions per kWh in the entire U.S., Honolulu Hawaii. There it produces the same amount of emissions as a gas car that gets over 400 MPG. It probably goes without saying, but it is a safe bet that there will never be a production gas car that gets 400 MPG.

What About Kids/Cargo?

One reason many people don't consider eBikes is that they don't think they can haul enough. These people probably haven't looked into cargo bikes and trailers much. After doing some research I bought a used Madsen bucket bike to chauffeur my kids around town with. It can hold 600 lbs of weight so it also works to haul groceries, bags of cement, whatever you can throw in it.

A Madsen can't really fit 4x8 sheets of plywood, but Bikes at Work makes a trailer attachment just for that! You can even go really fancy and build a Carla Cargo trailer. With its own integrated electric motor and brake this trailer can effortlessly pull huge loads behind any old bike.

There are cargo bikes and trailers that can handle pretty much anything you can throw at them. Add an electric motor and they'll glide effortlessly along while getting around 1,000 MPGe. Their up front prices may be in the thousands but they make up for this by having next to no operating costs. Just look at all these crazy cargo hauling contraptions!

How Much Do They Cost?

2020 eBike Prices
$ 500 Swagcycle
$ 800 Sondors
$1100 Ride1Up 500
$1500 Radrover
$2700 Super73-S2
$3300 GoCycle GX

High cost is a big part of why there still isn't an eBike in every garage. The prices of eBikes can vary wildly depending on price, quality and features. A tiny, but powerful, Swagcycle is just $500 while a fancy GoCycle GX costs $3300! Of course you can also build your own eBike to get the exact price/performance ratio you really want to.

With so many new eBikes coming out these models and prices will be outdated very quickly. There are also lots of sales on the old models and around Black Friday that can save you hundreds more. Check out the eBikes section at Electrek to see the latest models if you're considering buying one.

While all of these bikes may seem expensive when you compare them to cars they're downright cheap. Maintenance costs for eBikes are just a few bucks a year for things like brake pads, tires and chain oil. Even if you pay a fancy bike shop to do it it'll probably cost under $100/year.

Fuel costs for these bikes are so low they're almost non-existent. In the U.S. we pay between 9 and 30 cents per kWh and it can be even cheaper if you install your own solar panels. Even at 30 cents it costs less than 1 penny per mile and at 9 cents it's just 1/4 of a penny. If you pay $2.50/gallon and drive a 30 MPG car you'r paying over 8.3 cents per mile. If you ride an eBike for 100 miles instead of driving that car you will save over $8 on fuel alone.

Payback Time!

Of course $8 is a lot less than the $1100 purchase price of a Ride1Up 500 series. You'd have to ride that bike nearly 14,000 miles to pay for its cost on fuel savings alone. But of course there are more costs to driving than just fuel. There's maintenance, depreciation, insurance, etc. When the IRS added all this up they figured driving a car cost 57.5 cents/mile in 2019.

An $1100 eBike pays for itself in under 2,000 miles using the IRS cost per mile estimate. With a 10 mile each way commute it'd take less than 100 days of riding to pay for this eBike. Even if you drive every time the weather is bad you could still get this done in one year and the eBike will probably last well over a decade. The return on investment (ROI) of an eBike can easily be over 100%/year if you use it enough. The only other investments that can consistently return that much are Ponzi schemes.

If you're trying to have a profitable life it's important to choose the right tool for the job. If a eBike can handle a significant number of miles you use a car for then it is likely a worthwhile investment. This is true if you have to spend extra for a cargo eBike or a trailer or you run a cheap electric car that costs half the IRS per mile estimate.

Will the Battery Last?

One part of an eBike that might not last a whole decade is the battery. Batteries are rated in charge cycles which describe how many times they can be fully charged and discharged. An eBike battery should last hundreds of charge cycles, maybe even 1,000. If you get 25 miles of range from a full charge then going 1,000 miles would take 40 full cycles. If you get the full 1,000 charges from your battery it will take you 25,000 miles!

Given the stresses eBike batteries are placed under I don't think 25k miles is likely. The temperature extremes and high current draws eBike batteries face will probably degrade them faster than batteries that live cushier lives. Still 5-10k miles is certainly possible. Also, if your eBike battery does die while you're out riding you can always just pedal it home.

The other good news is that battery prices just keep falling. They have been dropping by around 20%/year for over a decade now. This is a big part of why eBikes from 10 years ago weren't great values, their batteries cost 10 times a much! Right now a good eBike battery pack can be had for $500. By the time you have to replace the battery on a new eBike this will be substantially less. It's crazy to think, but by 2030 an eBike battery may be cheaper than its tires.

Won't it Be Stolen?

Another big fear with bikes is that they'll get stolen. This is a sad fact of life in many places and will probably continue until we sort out a lot of deep underlying problems like drug addition and poverty. That being said the last time I had a bike stolen was in 6th grade and I've ridden thousands of miles since then. That childhood memory still haunts me though so I came up with a nearly free DIY GPS bike tracker. Its probably overkill, but it lets me sleep better at night.

Why Not Just Pedal?

Okay, so now you're probably convinced that eBikes crush cars, even electric ones. How do they compare to regular old pedal bikes though? Surprisingly, it turns out that an eBike has lower emissions per mile than even a regular bike. How can this be?

Food vs Electricity

To calculate the emissions of a bicycle you need to look at the emissions of the extra food a rider must consume to pedal that bike. This depends on what that food is and how fast the bike is going. The worst case scenarios, pedaling a bike really fast with meat heavy diet, gets around 50 MPGe. The best case scenario gives you 175 MPGe but it requires riding a bike under 10 mph and eating a low emission vegan diet, two things very few people do. My riding style/diet gets around 100 MPGe, which is better than any gas car but still well below a 1,250 MPGe Radrover.

Of course, the reality in America is that we eat for enjoyment and we often eat too much. The millions of dollars Americans spend trying to burn calories makes this pretty clear. We're going to eat that delicious burrito for lunch whether we go biking or not. In this case is it really right to attribute the emissions of that burrito to biking? It was going to get eaten no matter what and all the bike did was keep it from being burned at the gym, or padding our waistlines. From this perspective a pedal bike actually has an infinite MPGe.

If biking is truly causing you to eat more food then adding electric assist to your bike will help both cut your emissions and save money on food. How much money it will save can also vary dramatically based on what you eat. If you bake your own bread for 25 cents a loaf an eBike won't cut your grocery bill much. If you eat lots of steak, salmon and fresh vegetables then an eBike could easily save you $10/day on food. A cool feature of eBikes is that you can pedal as much as you want. If you have a crazy big lunch one day you can lower the assist level on your ride home to burn the extra calories.

Health Benefits

Pedaling a bike also provides a lot of health benefits from exercise. Getting some moderate exercise every day helps your body so much, and we know that more exercise is better (up to 90 minutes of exercise per day, after which we don't have enough data to say for sure). At the same time we've also found that eBike riders get about the same amount of exercise every day as regular bike riders. This is because eBikers use their bikes more often and go further on them, while still pedaling some. You also use your core muscles to steer and balance an eBike even if you aren't pedaling.

So What does Profit Greenly Ride?

With all this eBike evangelizing you probably expect that I ride one every day. If I lived in a bigger city I would certainly do this, but my town is downright tiny. Even with multiple trips around town it's hard for me to ride more than 5 miles in a day. I want the exercise I get from those 5 miles to help offset my burrito habit so I still pedal them. If my kids get too heavy to haul around, or I get injured or something I can certainly see adding an electric motor to my bike in the future.

I did buy an eBike for my wife's field work. This involves regularly visiting a nearby stream to collect over 60 pounds of water samples. She was renting a car for this for a whopping $40 a day! Even worse the closest it could be parked was a long walk away up hill from the sample sites. Her new Radrover and trailer setup can ride right down to the stream saving time and effort. By removing the $40 rental feel they will pay for themselves in just 40 uses. Considering that she'll be collecting samples from this area hundreds of times over the next few years this seems like a no brainer investment. Hopefully this example will help you think of some task you currently do with a car that could be more profitably done with an eBike instead.

Profit Wrap Up

If you went back in time and told someone from the 80's that in under 30 years we'd have vehicles that could get over 1,000 MPG they wouldn't believe you, but this is the amazing reality we live in. Even just thinking about how a bike like this generates less emissions per mile than on powered by your own muscles is kind of mind bending. Sure, it's still a good idea to get some exercise, but if you're using a car for short drives around town then you should really look into an eBike. It'll help you profit greenly with lower total emissions and more money in your bank account. Happy riding!

The idea of having a net zero home, one that generates as much power as it consumes, is very exciting. Some people are interested in it to help save the planet, others like the idea of never paying another power bill, or the freedom of energy independence. For a long time, net zero homes were so expensive and complicated that they were simply dreams for most people. In this post I'll explain how I did it, and how you can to.

The Two Keys to Net Zero

Technology has finally improved so much that retrofitting your old home to become net zero can be both simple and profitable. With two simple updates I was able to make my regular old house net zero. These updates cost a bit of money up front, but in the long run they will both more than pay for themselves.

In the old days, retrofitting a home to be net zero generally required making lots of changes to the house. You'd add insulation to the ceiling, walls and floor, air seal everything, update the windows, install a new HVAC along with a ventilator (this pumps fresh air into your well sealed house so you don't suffocate), update appliances, replace your lighting and who knows what else. This is all great stuff to do to a house, but the sheer number of tasks, along with the cost of it all has put it out of reach for most people. Luckily, nowadays you can turn most houses into net zero houses with just two changes. All you need to do is install a super efficient heat pump, and a big fat solar array then BAM, your home becomes net zero.

Step 1. Get a Big Fat Solar Array

Solar is the first key to easily converting your home to net zero and making money while doing so. A lot of people overestimate the price of solar because it used to cost a lot and they haven't rechecked the prices recently. It turns out that the price of panels has been falling steadily for decades now. Even if you did the math on solar and found it wasn't profitable for your home just a few years ago, it may well be so today. The price of installing solar on a home dropped over 60% from 2010 to 2017! All these price drops, along with the federal tax credit for installing solar means that if your roof gets decent sun you can now probably make money by putting panels on it. How much money depends on a lot of factors, which I delve into in my solar ROI post, but the key thing to realize is that solar panels now essentially pay for themselves and beat pretty much all "safe" investments.

WARNING: The Federal Solar Tax Credit (also called the Investment Tax Credit, or ITC) has dropped from 30% of total install cost in 2019 to 26% in 2020. It was going to drop again to 22% in 2021 but has been extended to stay 26% till 2022. In 2023 it'll drop to 22%, then it's gone for residential installs in 2024. Even if solar costs keep falling as they have, a system installed in 2022 with the 26% tax credit will be cheaper than a system installed between 2023 and 2026, maybe longer. I'm impressed that Congress extended this credit but I doubt they'll do it again.

Efficiency Improvements Vs Solar

Because solar can now pay for itself, cost concerns shouldn't limit the size of your array. Having a higher energy demand simply allows you to make a larger profitable investment in solar. Back when solar prices were higher and people were essentially losing money for every panel they installed, it made economic sense to do lots of efficiency upgrades to keep arrays as small as possible. Now, most people are better off simply building a bigger solar array instead of making lower ROI efficiency improvements.

An efficiency improvement only makes economic sense if the same money spent on solar will generate less energy than that improvement will save. It's surprising how often solar wins in this calculation. For example, I know many people who have installed new windows in their homes. It's pretty common to spend thousands on this, often over $10k. If that same money were put into panels instead, they would produce far more energy than those new windows will save. There are still some efficiency improvements with high enough ROIs to be worth doing, like upgrading bulbs to LEDs, adding insulation to a very poorly insulated attic, and DIY caulking and spray foaming to seal air leaks. In general, though, the price of solar has dropped so low that simply building a larger array is now usually the most profitable choice.

Where To Put Your Array

There are some limits on the size of an array your house can support though. Here in the northern hemisphere, you want to put all your panels on the south side of your roof because the tilt of the Earth means that the sun is shining more from that direction. If your roof doesn't have that much southern facing space, or it is shaded by trees or another building then that might limit the size of an array you can profitably install.

Of course, you can always think outside of the box and install an array somewhere other than your existing roof. Building a new shed, outbuilding, or car port with a sunny, south facing roof will cost more money, but it can give you a nice space to add more panels and increase the usability and value of your home. If your outbuilding is more than just a frame with solar panels on it then it may not be the obvious economic slam dunk of putting panels on your existing roof. But, this is because you're adding a usable building as well as solar, so you have to factor that in.

Step 2. Get an Efficient Heat Pump

A heat pump is the one high ROI efficiency improvement that usually makes a bunch of sense to pair with a solar array. Read my Heat pump ROI post for more details.

From a whole house perspective, heating and cooling are usually the top energy uses. A lucky few can avoid this by living in a tropical paradise where their home's climate can be controlled by cool ocean breezes. For the rest of us, upgrading our HVAC system to be all electric and super efficient is the next key to making our homes net zero.

Even just a few years ago this wasn't possible for people who lived in colder climates. Heat pumps made in the 90's and even early 2000's just couldn't put out enough heat when the weather got cold. But now heat pump technology has gotten so good now that they can efficiently heat homes even in cold places like upstate New York.

There are plenty of other ways to cut down the HVAC use in your home. The simplest is to just turn down the thermostat, but there's always a limit to how far people are comfortable going with this. The other options that have been recommended for years involve air sealing, adding insulation and updating your windows. Those can all still be great choices, and if your house is in really bad shape you might need to do some or all of them. But, the amazing price and efficiency of modern heat pumps crushes most of these other options.

Upgrading to an efficient heat pump can cut the HVAC energy use of your house by more than HALF! The only way upgrading your windows will cut your home heating bills in half is if your current windows have multiple gaping holes in them. If this is true for your home, I recommend investing in some duct tape stat! Otherwise upgrading all your windows will generally cost more than buying a new efficient heat pump, so why do them first? Heat pumps have the added benefit of working as efficient air conditioners as well as heaters.

The ins and outs of how heat pumps work and why they can be well over 100% efficient are best saved for another post (or you can watch this detailed video). The key thing to know is that a good heat pump can pull over 3 Watts of heat into your house while using just one 1 Watt of electricity. Old electric resistance heat adds slightly less than 1 Watt of heat for each Watt of electricity and oil and gas furnaces are even worse. This means that a heat pump can cut the size of solar array needed to make a home net zero by a lot. The price for that heat pump is almost certainly lower than the panels it is replacing, or other traditional energy efficiency improvements like windows or insulation.

Finally, because a heat pump runs on electricity, your solar panels are able to power it. This means that you can power your own HVAC, the biggest power consumer in your home. Oil and gas furnaces rely on someone else delivering that fuel to your house. You have to pay whatever price they're charging, and if they don't deliver, you're left in the cold. With a heat pump and solar combo your roof is creating the power you need to heat your home.

The one issue with this is that solar panels often create less power in the winter than a heat pump needs. Most people in the U.S. can essentially use the electric grid as a giant battery to store the extra power they generate over the summer until they need it in the winter. This is complex enough that it deserves its own post as well, so I'll just keep to the financial side here. If you're in a net metering state you can size your solar array so its total annual generation matches the total annual consumption of your home and pay $0 for electricity. If your state is one of the few that doesn't yet have net metering then this guide is probably not the best way for you to go net zero right now.

Real World Numbers

House Stats:
Built: 1960s
Sqft: 2200
ACH: 0.32 
Attic: R38
Walls: R3
Windows: Old

My family moved into a regular old house in central Pennsylvania over a year ago. It was built in the late 60s and while it has decent air sealing, its insulation is lacking and most of its windows are original. A deep energy retrofit would have improved all of these areas, but it would have cost more than my heat pump and solar combined and our house still would have pulled more energy from the grid than it produced.

Putting a big solar array on our roof cost $24k after tax rebate and upgrading our old oil furnace to a high efficiency heat pump cost another $15k. These two updates allowed us to generate over 11,000 kWh in 2019 while only consuming 10,000 (those extra kWhs are for an EV we'll get some day). We made $1,382 from our solar panels and saved around $1,000 with our heat pump, so $2,382 in total. That's over a 6% return on investment (ROI). Of course both of these amounts are not taxed so if you factor in a 15% long term capital gains tax the ROI goes up above 7%. There are plenty of stocks that returned over 7% last year, but they could all well lose money this year. Our solar panels and a heat pump on the other hand will keep returning this much money year after year unless there's a huge drop in electricity prices, which is very unlikely.

Why Not Just Do Solar And Old Electric Heat?

We could still heat our home with electricity using those old resistive electric heaters (like the inside of a toaster). This would be far less efficient than our heat pump and probably pull and extra 6,000-9,000 kWh more. We'd need to install more solar panels costing $13k-$20k to generate this extra electricity and the resistive heaters themselves would cost over $1k to install. This means we'd be spending $14k-$21k to heat this way instead of the $15k we paid for our heat pump. The $15k we spent seems like the lower priced option, and I've discovered a few tricks for my heat pump that should make it even more efficient next year. Also, our roof is already full of solar panels and we don't have an obvious place to put more.

Step 2a. Convert All Appliances to Electric

If you already have an electric hot water heater, stove, and dryer then you can skip this. If any of these are powered by gas though. the solar panels on your roof won't be able to power them and you won't be able to be truly net zero. Converting them to electric is the final step in making it so the energy you produce can power your entire home.

If you want to still cook with gas there has been a lot of progress on generating biogas from food scraps, but it's still a niche technology. This post is all about making the net zero conversion easy so I'll leave the biogas stuff for another day.

Won't Converting From Gas Lose Me Money?

It is true that gas was pretty dang cheap in 2019. You could get a therm of gas for just over $1.00 in the U.S. last year. It takes about 29 kilowatt hours (kWh) of electricity to equal the energy content of 1 therm of natural gas. If your kWh comes from a utility, it probably costs around 11 cents, so $1 of gas has the same energy as $3.19 of electricity. If you install solar you're probably reducing your true cost per kWh to around 7 cents (possibly less) so for you it's only $2 for an equivalent amount of energy. A good heat pump powered by this cheap electricity beats a gas furnace because it delivers 3x more heat from the same amount of energy.

There are heat pump hot water heaters that can beat gas hot water heaters by a similar amount, but they aren't for every home. Most draw heat from air inside your house so they need a bigger area than many homes have set aside for a hot water heater. This also means that they are taking energy your heat pump added to your home during winter (Sanden makes one that pulls heat from outside). On the flip side, in summer they give your home some free cooling, which makes a ton of sense in warmer areas.

Even regular old electric water heaters may be able to beat gas if you have low total gas usage. These units may be only 10-25% more efficient than a gas model so you might assume the lower price of gas beats them. This ignores the gas monthly fee though.

MATH TIME!
$1/therm*(1+75% fee)
  = $1.75/therm
1.75/29 kWh/therm 
  = $0.06/kWh
$0.06/80% 
  = $0.075/kWh
0.075/$0.07/Solar
  = 1.071 
1.071 - 1*100 
  = 7.1% more

In a previous house I paid $16/month for gas service and used around 550 therms of gas per year. This monthly fee increased my true cost per therm by 35%. Over half of that gas went to the furnace so if I had replaced that with a heat pump the monthly gas fee would have increased my true cost per therm by 75%. In this case an 80% efficient gas furnace would actually cost 7% more to run than a solar powered electric resistance unit (see math on the side if you want to check my work).

Once you get rid of the gas hot water heater, all you have left is a gas stove and dryer. These appliances will have math similar to the resistance hot water heater above, except their lower energy usage means the monthly gas fee will increase the true cost per therm for them even more. If you've accepted that it's a good financial choice to convert your hot water heater then it'll be an even better financial choice to replace your dryer and stove.

In the end, replacing these appliances gives a lower ROI than solar panels and a heat pump. Getting them done is still a financial benefit though. Doing so also eliminates combustion in your house, improving every day indoor air quality and eliminating the risk of your whole family dying of carbon monoxide poisoning. You can go fancy with a heat pump hot water heater, condensing dryer and induction stove, or you can just use the regular old resistance heat models. Either way you'll make money and get a house that is entirely powered by the sun.

Step 3. Profit!

Hopefully this post has shown you how it can be both easy and profitable to convert your home to be net zero. Just get solar panels and a heat pump and profit. If you don't already have electric appliances then it's a tiny bit more complicated than just these two steps, but not by much. If, in the future, you better insulate and air seal your home, you may find your solar starts generating more power than your home uses. All you have to do to solve that is buy an electric vehicle to use the excess. This is something most everyone will be doing in the coming decade or so anyways, so it's fine to expect it. Hope this has helped you, and if you have any questions or want to share your own story of going net zero please do so in the comments.

Recently, there's been a big push to get colleges and universities to sell their fossil fuel holdings. This divestment movement has often hit resistance from administrators who say that their endowments should be invested to produce the maximum return on investment (ROI). What if it turned out that those endowments were already not maximizing their ROI because they weren't investing in solar panels to power their schools? University endowments are hurting both the world and their bottom lines by this inaction. Read on to find out why.

How Endowments Work

Endowments are huge piles of money that colleges and universities have managed to sock away over the years. They generally came from alumni donations, and their growth is spurred by their schools' tax exempt statuses. These piles of money are invested in various stocks, bonds, etc. with the goal of getting good but stable returns. Some percentage of this return may go back into the endowments, but most is used to help fund the schools. The dream scenario for a school is to be 100% funded by its endowment so that it wouldn't need to collect tuition or beg alumni or government entities for money, but the reality is that spending will always increase well before this happens.

The Crazy Huge Pot of Money

There is a crazy amount of money in school endowments. There are more than 100 U.S. schools with over $1 Billion in their endowments and the top 10 endowments total over $200B on their own. Most schools spread their investments across a myriad of stocks and bonds. More aggressive endowments like Yale even invest directly in startups.

Yale is considered one of the top endowments with over $30B in assets and average returns of over 10% annually for decades. Other endowments look in awe at Yale's results and often try to follow their lead. Yale has innovated by really spreading their money around, as you can see in the chart on the right. Though they have less in the way of bonds and cash than many other endowments have held in the past, these assets still amount to 7% of their portfolio - over $2B - which I probably don't have to mention is a TON of money. Cash has almost no ROI and bonds offer only around 3-4%, but both provide stability to the endowment as a whole. They won't go up in value a bunch, but they won't drop either. The thing is, solar panels and other provide a greater return with even less risk.

How Solar Beats Bonds

The fact that solar panels have a higher ROI than bonds is the key thing that endowment administrators are missing. I go over the math of this for a residential home in PA in my solar ROI post. The basic gist is that if the price to install a solar panel is less than the value of the energy it will produce over its lifetime then it will have a positive ROI. This seems like a low bar, but it's reasonable considering that over $16 trillion is currently invested in bonds that guarantee they will return less than you invest in them. These bonds are invested in to reduce overall risk, but there is still a chance that they will not pay out. Solar also has risks, but they are low too.

Solar Risks

1. The solar panels stop making electricity

2. No one will buy the electricity they produce

3. The price of electricity drops

Luckily these risks are all very low. Most panels are warrantied to keep producing power for 25 years or more so it is very unlikely that they'll stop working. It is also cheap to buy insurance for the rare case of them being destroyed by something like a tornado and its price can be factored into the initial ROI calculation. School's don't have to worry about the risk of no one buying their power because their operations have a large power draw already. They can simply guarantee that they'll sell the power to themselves. They can even install less than 100% of their current demand to reduce the risk that they'll lack a market for their power further.

The biggest long term risk for solar panels is that the price of electricity drastically drops. If that happened the electricity that the panels produce will drop because a kwh of electricity will be worth less. This could drop their return below their cost so it is a real risk. That being said electricity prices have been rising for decades. Our increased understanding of the dangers of climate change is only going to raise prices further. In the end it's far more likely that prices will continue to rise and that solar panels will produce more monetary value in the future. Buying a bond is making a bet that the issuer will still be able to pay you in the future. While it is very unlikely that a bond issuer like Germany goes bankrupt in the next 30 years, I think that is more plausible than the average cost of electricity going down over that time frame. Solar panels are a bet smart investors should be happy to make.

A Couple Caveats

The math for solar ROI also changes for large institutional size installations. For example a big institution may have negotiated a lower electricity price than regular residential customers pay. At the same time the price to install a solar panel in a large commercial array is about 1/3 less than what smaller residential customers pay. Many universities also don't benefit from the tax breaks for solar because they don't pay taxes. This hasn't kept other smart entities from sharing the tax credit with a for-profit company and still reaping the benefit. When you add it all up solar is still likely cheaper than grid power for many large institutions which means it will have a positive ROI.

Where Are The Huge College Solar Arrays?

If solar is so much cheaper than grid power then why aren't we seeing huge arrays being deployed at a bunch of schools? Well, this is starting to happen. For example, Penn State is projected to save $14M over the next 25 years by contracting to buy 25% of their electricity from a new solar farm. This is with almost no investment on Penn State's part so the ROI is essentially infinity. If they did invest some of their endowment money to own part of the solar farm company themselves they could capture much of the profit that company is making and encourage building an even bigger array. The ROI on this would almost certainly beat the low ROI of bonds.

Over Caution = Loss

Penn State thinks they're being "cautious" with their move into solar by still buying most of their power from the grid. But, as the huge savings from solar start materializing the school will hopefully realize that their "caution" is actually leaving tens of millions of dollars on the table by not going 100% renewable. This will continue being true until policies around renewable energy become more stringent. Schools would be smart to install their large solar arrays now while the rules are still quite favorable and bank on being grandfathered in.

The Money's There

The cost of installing a solar array to replace 100% of a school's electricity with renewables is far less than the value of many school endowments. In the case of Yale it is far less than just their investments in low return bonds. Remember that Yale has over $2B in cash and bonds right? Yale is in Connecticut where the total solar investment in the entire state is only around $1.7B and that's enough to power around 90k homes.

The price to install solar has fallen so far that Yale's $2B of cash and bonds could nearly triple the amount of installed solar in the state. Of course Yale doesn't even have 13k students and they live in dorms that use less energy per person than regular houses. Yale would only have to move a small fraction of the money they have in cash and bonds into solar to get 100% of the school's electricity from renewable sources. This solar would almost certainly have a higher ROI than their cash/bonds while also helping mitigate climate disruption. So what's the problem? Are they dummies who don't know how to maximize their returns? Are they soulless ghouls who want to spur on climate change? I'm hoping it's neither of these.

Fear of Physical Assets

I think the real thing that is holding up investment in solar is a fear of physical assets. Finance people often want to just buy shares of companies. They want to read a prospectus rather than research the value of a hard asset. If they did do a bit of research into solar PV they'd realize that owning a solar array is barely more complicated than owning a share of stock. Yes, they'll want to hire a good company to install it, and pay for insurance one it but once that's done there's next to no maintenance. They could hire people to clean snow/dust off the panels, but honestly the array will probably produce a profitable amount of power without this. So what's really left to fear?

Why Doesn't Yale Start a New Trend?

The administrators of Yale's endowment have said that "what endowment investing [is] all about: perpetual institutions and their long-term health". The scientists and economists employed by Yale understand that not transitioning to renewable generation will create long-term instability for the entire planet, which obviously includes Yale. The university already has a plan to become net zero by 2050, but that is a long time away. Every day they wait to move money from bonds to solar means more carbon emitted and more dollars lost. When will the directors of Yale's endowment and others wake up to the fact that building renewable energy to power their schools will return more than their current "safe" investments? When will they start pushing the university to install renewable generation as fast as possible just for the economics of it? When this happens will it start a trend among other school endowments the way so many other Yale investment strategies do? Will some other school beat Yale to the punch and show the world how renewable energy lets them profit greenly? I don't know the answers to these questions, but if you work in school endowment investment I hope you've got a team of people looking into this now.

The holidays are here again. Americans will spend over $1 trillion in the next month. Much of this will be on worthless junk whose only purpose is to momentarily entertain our kids. If we gave gifts that actually replaced "regular" needed shopping we could save resources while still bringing our kids joy. This year try heading to the hardware store for presents that are fun, useful and money saving.

Radio Flyer Wagon vs Gorilla Cart

One of the most traditional gifts you can buy a kid is a good old Radio Flyer Wagon. The one I linked here costs just under $140 and would let you pull a couple of kids around happily. Alternatively, you could spend just $60 to buy a Gorilla Cart with a max load rating of 600 lbs! This saves $80 and removes the need to buy a regular wheel barrow or yard cart. The Gorilla Cart is far more durable, as the wood sides of Radio Flyers have a tendency to break when subjected to abuse from small children. It also has a fun tipping feature that easily lets you dump whats in it. Kids love helping dump a bunch of mulch out with it and then climbing in for a ride. They'll also enjoy owning this useful thing and having adults ask their permission to use it. Honestly the joy they'll get out of that alone is probably more than the Radio Flyer would ever provide them. Why spend more on something that is less durable, less fun and less useful?

Toy Snake vs Garden Hose

I discovered this idea while my kids played around with some friends after school one day. The kids found one of those flexible hoses and were running around holding it pretending it was a snake. They loved slithering it around trees, through a bike rack, wherever. Why buy them a fancy 100 inch long stuffed snake for $40 when you could spend just $30 on a 600 inch long expandable hose? You need a hose for your house anyways, and if it can double as a toy snake all the better. Intense toddler play could put a hole in the hose, but this is unlikely and it'd still be useful as a toy and bigger/cheaper than the alternative. Sure your kids will have to use more of their imagination to turn the hose into the snake, but isn't this something we want to be encouraging as parents?

Actual Wood vs Expensive Block Set

You can easily spend $90 on this fancy block set. Or you could spend $9 on this 3 foot oak 2x2. Set up a stop block on your miter saw and cut that into 22 1.5x1.5x1.5 blocks in just a few minutes. You can buy a cheap saw+miter box for $15 if you don't already have a saw. Buy a 6 foot oak 1x2 for $6.58 and you can make another 22 .75x1.5x3 planks. That's just over 15 bucks for over 44 quality oak blocks.

A little more money gets you some sand paper and a few small cans of non-toxic wood stain from the store, the total will still be less than half the fancy blocks. For this project you may want lots of colors, instead of buying them all in big cans just get small "sample" size containers of each color for a few bucks from the paint store. If you've got a drill press you can easily put holes in these and add some rope or dowels to expand the possibilities of play. Bonus points if you get some older kids to help with this project.

Fancy Kids Step Stool vs Utility Stool

Another common kids gift is a small stool to help them get up to the sink in the bathroom. This is a truly great thing to have as it lets your kids become self sufficient sooner. Seeing a two year old climb up to the sink to wash her own hands is a beautiful thing. Just be careful, you could also see that same two year old splash water everywhere.

As far as stools go amazon has some nice little fold up stools for really reasonable prices. This one sells for just $9.50. The only problem with them is that they only work for a very small window in your kids lives. Another option is to buy a stool that will continue to be useful for decades to come. At $25 this 2 step utility stool costs a bit more than the amazon one, but it lets kids get up higher and is useful for adults as well. The only thing I don't like about it is that it can get in the way a bit because it doesn't fold up, but that lets it hold up a lot better when covered with toys, so its not all bad.

This recommendation is a closer call than the others. If you feel like the adults in your house are often in need of a step stool then maybe consider spending more on the bigger adult model. If the stool will truly just be for your kids then get the cheap one and pass it on to another family when your kids outgrow it.

Leaf blower vs Anything

The final recommendation I have is that your kid would probably love an electric leaf blower. There are corded models out there (like this one) that cost under $20! Think of how many kids toys cost $20 or more these days? Think about how utterly useless most of them are. These cheap electric blowers aren't the most useful but they can still do a lot of small jobs. They can blow dirt out of your car, dust out of your garage, and do some fine outdoor cleanup that brooms just can't handle. On top of that kids LOVE them.

Low powered blowers are actually better for kids because it makes them so light a 3 year old can hold them. Being electric you also don't have to worry about mixing oil, pull starting, or noxious fumes. Just be sure and give the kids some ear protection if the one you get is loud. Kids can blow leaves, sand, water, even their friends' hair. If you already have a battery powered mower then you might even be able to find a good deal on a cordless version that uses the same batteries (if you don't already have an electric mower you should really give them a look, they've gotten amazingly good the past few years).

Wait, How is This Green?

At this point you may be wondering to yourself "Why is a blog that's supposed to help me save money and reduce emissions recommending I buy a bunch of stuff I don't really need?" Well, you're right, if you want to be living your best life you shouldn't buy any of this stuff. With humanity rapidly approaching an amount of emissions that will disrupt civilization for centuries to come the best presents we can give our kids and grandkids are ones that will reduce humanity's overall emissions. But, not everyone is ready to become an eco-hermit yet. I accept that few families are going to give their kids solar panels and heat pumps for Christmas. These would indeed be awesome gifts, but they're pricey and kids can't really play with them. So instead I tried to give some more realistic gift ideas.

My hope with this guide is to help get people thinking about gifts that can be fun and replace some other form of consumption at the same time. It's an added bonus that these gifts also save money, which can eventually pay for larger improvements like solar. While you're at the hardware store you can also spend some money to cut your home's energy use. You will almost certainly save money and energy by buying LED bulbs, attic insulation, weatherstripping for doors and windows, window pane insulation, and spray foam for all the holes in your home. Maybe wrap these things up and put them under the tree for the adults in your life too?

Riding a bike instead of driving is one of the most profitable life choices you can make, along with one of the greenest. It can literally save you tens of thousands of dollars over just a few short years and keep tons of carbon out of the atmosphere. All of this savings can quickly be erased if your bikes just keep getting stolen though. Today I'll show you a cheap and easy way to help avoid bike theft, and catch the perps.

UPDATE: Since writing this I have converted my cargo bike to an eBike and installed my GPS tracker in an even harder to find/remove location underneath the bucket itself with a separate USB battery pack to keep it running for extra time. Scroll down to the How Hard Was It? section of my eBike Post for more details.

Why not just buy a lock?

Most people just buy a bike lock to keep their bike safe. The problem with this is that it only really deters casual bike thieves and it can cost a lot of money. You can spend over $100 on a seriously beefy lock, but even that can be defeated with around a minute's worth of lock picking or angle grinding. The best locks can also make it hard to actually find a spot to lock up your bike because they're thicker with less room inside their shackles. If you have a huge lock the thief might just leave it alone and cut whatever you've locked it to. Locks like this can also easily weigh over 4 lbs, adding a significant amount of weight to your bike. Instead of spending big on a fancy lock, I recommend just buying a cheap U lock and then hiding this nearly free DIY GPS tracker on your bike.

Why not just buy a GPS tracker?

There are numerous bike GPS trackers for sale and at first you might be tempted to buy one of those. The problem with these options is that they have medium to high up front costs and their monthly fees will add even more over a few years of use. You could spend over $100 for something like a Spybike and then another $4.50/month forever, or worse yet $50 for a GPS tracker from amazon and then $25/month forever.

WARNING: These hacker instructions use the outdated GSM network (also called 2G). This network is being phased out cause everyone's already moved to 3G and 4G, and will soon be going to 5G. The GSM network might not be around for much longer, even now it is a pretty spotty network

To save money you could go the hacker route and whip one up from raw parts for under $20. Unfortunately not everyone owns a soldering iron and far fewer people actually know how to solder. Even if you do this takes additional raw materials which is not so green. So what is a frugal, green, non-electronics nerd who wants a long lasting GPS tracker for their bike to do? The answer is simple, just grab an old Android phone and a Google Fi data only SIM card. Okay that sounds confusing, let me explain.

Why is Google Fi Needed?

If you haven't heard about it yet, Google Fi is a great, cheap new cellular network run by Google. They don't own their own towers, but instead rent out the towers of other providers (in the U.S. they use Sprint, T-mobile and U.S. Cellular together). This gives them solid coverage but at a low price. Even better, their coverage works worldwide with no data roaming fees. If someone steals your bike and gets it into Canada before you notice, your phone will still be able to send you its location over the Fi network at no extra charge! Most people pick Fi because of the low monthly cost or free international roaming, but for this project the standout feature is its $0/month data only SIM Cards.

$0 per Month Surely You Must be Joking!

I am serious and don't call me Shirley. If you already have a phone with service on Google Fi they will send you a data only SIM card that you can slide into another phone or tablet for free. I didn't even have to pay shipping! Once you plug this SIM into your old phone and start using it there is no monthly fee, you just pay 1 penny for every MB of data you use. Since all your GPS tracker phone will be doing is sending tiny amounts of location data it is likely that it will only use a few MB of data each month. This is a much better deal than the $60/year connection fee of Spybike, or the $300 yearly price of those "cheap" Amazon GPS trackers.

Of course to be able to get a nearly free data only SIM card you will have to move at least one of your phones to Google Fi. You're probably already paying more per month with your current carrier so this switch will likely save you money. You can thank me later (or thank me now by signing up to Fi with my referral link, it'll give us both a $20 credit). Just make sure the phone you're switching is compatible with Fi.

Google also often runs promotions to get people to switch. Last year around Thanksgiving they gave a $200 credit to people who brought their own phones. Pairing this with the $20 referral link credit I was able to buy my wife a Moto X4 from Amazon for $9 (well $229 with $220 worth of Google Fi credit). Of course if your current phone is still working fine you can take the even greener route of not buying a new phone and just pocketing whatever credit they offer.

Your old phone to the rescue

Of course once you've got your data only SIM card the next question is what to do with it. The first thing to do is look to see if you have an old phone hanging around. You probably gave up on your old phone because it started feeling super slow, or its battery was draining fast, or its screen was kind of smashed. That's fine, none of these things really prevent it from being an awesome GPS tracker (though a smashed screen may make setting it up a bit harder). If your last phone is just totally gone you can also ask your friends if they've got one laying in a drawer somewhere. Worst case scenario, you can buy an old used phone for under $50 on ebay.

Setting it Up

My old phone wasn't lasting 12 hours per charge when I gave up on it. Just doing GPS on my bike it now lasts well over a week between charges.

Now that you've got an old phone to be your new GPS tracker, you should create a new dummy gmail account for it. Next, wipe the phone clean and set it up with your dummy account. This will also delete all your old personal info off it and also remove all of the apps you had installed that were silently draining its battery in the background. The one app I do install on the phone is IFTTT which I use to help manage the battery.

IFTTT setup

IFTTT is a great free app that lets you automate things on your phone and computer. It isn't completely required for this project, but it makes everything run much more smoothly. First I use this applet to send me an email any time my GPS phone's battery is low. That way I don't have to be constantly digging it out to check its status. You get one email when it hits 15% battery and another at 10% and 5%. I also use 2 other applets to manage wifi. This one turns off wifi when you unplug to save power. This one turns on wifi when you plug back in so your phone can update any software it needs to (I disable cellular later on updates to save power and cellular data). You could do all these things manually if you don't want IFTTT, but having them happen automatically sure makes things nicer.

Now we want to do one final update and then turn off everything we can on the phone to reduce its power and data usage. First, go to Settings->System->System Update and ensure that your phone is totally up to date. Next, search for "Data Usage" in Settings. Google calls the exact setting you want different things in different versions of Android so it's a little confusing. You're trying to get to App Data Usage, or Mobile Data Usage, or whatever they end up calling it in the future. Once there you can click on your different apps and disable background data for them. The two that you really want to turn off are Google Play Services and Google Play Store. These used over 150 MB of data the first month I used my GPS phone and who knows how much battery life. With them off my phone is slowly getting out of date, but with IFTTT turning on wifi whenever I plug it in to charge it should be fine. I think the only apps that you need to keep mobile data on for are Google Maps and IFTTT, but the other apps usages were all so low I left most on out of laziness.

Turn off wifi, and bluetooth and set the screen brightness to minimum. Finally shut off the phone, remove its old sim card and put in the new Fi data only SIM.

Now comes the easy part, setting up your GPS tracking phone. Turn it off and put the new Fi sim card in it. Turn it back on and add your primary email address as a contact. After this you can open up Google Maps, click "Share my location" and select your primary email to share with. At this point your regular phone should buzz and you'll be able to use it to see where the other GPS phone is. My Maps app gave me the option to make an icon on my home screen that takes me right to location tracking of my GPS phone. This will also show me the battery level of the phone, but since I have the IFTTT email on low battery set up I don't use it much.

Google Maps location sharing also shows how long ago the gps reading was made. I think Google saves battery life by only updating location if the phone's accelerometer detects that it is moving. If the bike has been sitting stationary in my garage for an hour then it will say just "60 minutes ago".

Find My Device

You could also set this up without sharing your location using google maps. To do it this way you just use Google's Find My Device website or phone app. The annoying thing about this is that you have to sign in to your google account to access it. It will also make an alert sound on the phone you're finding, which could make the thief aware of the hidden GPS phone if you didn't turn the volume down. The cool thing about it is that it easily links you to a timeline map of where you GPS phone has been recently. This can be useful to see what route the the thiefs took it on. You can also access this map by logging in to your GPS phone's google account on a computer and going to https://www.google.com/maps/timeline.

Bike Setup

Once the phone is set up you need to figure out how you're going to attach it to your bike. I ride with a waterproof pannier pretty much wherever I go, so I just threw it in there. Well, actually I hid it in an old plastic box I had laying around and then put it in there. I figured if a thief saw a phone in my bag they might be smart enough to turn it off, but now it'll just fade into all the other junk I have in there. My panniers are also really easy to take off and I often end up taking them inside with me for fear of them being stolen. Now, I can leave one on the bike and if someone steals it without the bike I will be able to track them down. Of course, if someone steals my bike right after someone else stole my pannier then I'll be sad, but that seems like a really unlikely series of events.

If throwing the GPS tracking phone inside an old plastic box doesn't seem safe enough you could try other options. If you have a rear rack you could duct tape it underneath it (probably put it in a ziploc baggie to keep it dry and make sure it isn't too hard to open that up get to the phone's charging port). If you have water bottle holders you could buy a waterbottle that is big enough to hold your own phone and then just put hide it in there. Just make sure you don't accidentally go and fill it up with water! On my Madsen cargo bike I hid it in a little tool box I've attached under one of the kid's bench seats in the back. If you want to get really stealthy you could add a Qi wireless charger to your phone and attach it to the bike in a way that is completely inaccessible (like totally cover it in duct tape underneath your back rack). Then you'd just charge it by putting a Qi wireless charging pad on top of it. Personally I think this is overkill so I'm saving $40 and just charging it with my regular old phone charger every week or so.

Wrap Up

Hopefully you've found this post helpful and are well on your way to building your own DIY GPS bike tracker for free. There are definitely a few ways this project could be expanded. I've thought of using IFTTT or a custom app to alert me if my bike is moving when my regular cell phone is not near it. This could also be a way to track the total miles and average speed of your biking, or to set up an always on camera on your bike to record (and maybe even prosecute) dangerous actions by car drivers. If you add any of these features to your DIY GPS tracking phone I'd love to hear about it. I think it's unlikely that my bike will ever be stolen, but if it is I'll be able to tell the cops exactly where to go to find it. Don't let fear of bike theft is keep you from profiting greenly. Use your old phone to build this little tracker and get back into the saddle!

Cars are one of the major sources of pollution in the world and a huge drag on people's wallets. Right now we're at the start of a massive shift in car technology. If prices for batteries and EV motors continue their downward trends then new EVs will MSRPs similar to gas cars sometime between 2022 and 2024. This is really quite soon and as people start to understand that EVs have much lower maintenance and fuel costs than gas cars the transition may be quicker than many people are currently anticipating. How this will affect the prices of cars, both new and used is a very interesting question that has a direct impact on your financial life. Should you buy a used Tesla now? How about a hot new Dodge Hellcat or a "practical" Honda Civic? Read on to find out.

What's happening to EV Prices?

We can already see one outcome of the quick advance of EV tech in the fast depreciation of old EVs. Leaf's that cost over $25k after rebates 6 years ago are now selling for $5k, Tesla's that cost $100k are now selling for $30k. This level of depreciation on cars with just 50-80k miles on them scares a lot of people away from EV purchases. I expect it will just keep happening to current EVs as well, but the reality is that it may be even worse for new gas cars.

In 5-10 years what will a current EV go for used when when brand new EV's offering similar range are selling for $20k new? What price will people pay for a used Bolt EV with 250 miles of range when there are new EV's with 500+ miles of range selling for $35k? Will someone want an old Tesla that takes 20 minutes to add 130 miles of range at a supercharger when new models can add the same amount in 5 minutes?

While the motor/battery is the main cost component in a car there are lots of other parts that have value. The body, wheels, glass, etc. is all worth money. This means that people won't just throw old EVs out, but their prices may fall just as much as the prices of today's 2012 Nissan Leaf's.

It is also possible that retrofit companies will start coming up that can add new batteries/motors to existing EV bodies. This could give them the same sort of performance as new EVs for a lower price. Currently there aren't a lot of service stations that specialize in retrofits like this, but it's actually not all that hard to learn. The main issue is that batteries are currently still expensive so retrofits are pricey. As batteries become cheaper and demand for service on gas cars drops I expect a number of savvy service station owners to start offering battery/motor upgrades to customers.

How Will the EV Transition Affect Gas Cars?

Another consequence of increased EV ownership is that demand for gas will drop. This will likely cause the price of gas to drop, but there is a of floor to how low it can go. This floor comes primarily from two causes. First off, there are some sources of oil which will simply be unprofitable if the price of oil falls too far. Oil from the tar sands in Canada may have already passed this point and be surviving on investor cash and government bailouts. This means that if oil prices drop too low then supply will also drop. This dropping of supply may the result in a boost of prices that enables high cost oil extractors to operate again, but such a boost could also push more people to switch to EVs thus dropping demand further.

The other factor in a price floor for oil is that it has uses beyond just fueling cars. While over half of the world's oil is currently used for transport a large amount of it goes to heating homes and producing things like plastics. As more people switch to EVs and the price of oil drops these other oil consumers might take advantage of the low price to increase their consumption. This would provide another upward pressure on the price of oil. So in the end, a surge in EV ownership may not drop gas price as much as people currently think.

Another outcome from less total demand for gas is that a lot of gas stations will close down due to lack of business. As it is gas stations make most of their profit on the sales in their convenience stores or through add-ons of additional services, such as car washes. If people are stopping at them less to fill up, then they'll be consuming less of these other services as well and some stations will be force to close.

A few old gas stations may find new lives as EV charging stations, but there won't be tons of demand for this because so much EV charging gets done at home. It is likely that there won't be lines for gas as stations close down, because a second station would open up to serve that demand and profit on selling lottery tickets and coffee, but there will be fewer places to fill up. This lowered number of stations means less competition and increases the chances that the ones still operating will try and overcharge customers for gas and gas car maintenance.

So how will all of this impact gas car sales? Certainly gas car sales will drop as people choose to buy EVs over gas cars. This will likely reduce the number and variety of new gas cars that are made as automakers will have trouble finding enough demand to make all the gas models they currently produce. I'd expect that used gas car prices would drop as demand for gas cars drops, but this reduction in new gas car models could help keep the prices of used models higher for a while. Still eventually the price of used gas cars will hit a cliff too as gas/maintenance becomes harder to find and new used/EVs also fall in price. Who knows, maybe old gas cars will start being retrofitted as EVs as well?

Wrapping it up

The million dollar question is when will demand for gas cars finally dry up. I'll leave the exact answer to this to an enterprising economist who wants to really get their hands dirty with the data. I am confident that the EV transition will be in full swing in under a decade though, and that this will result in far lower resale prices for used gas cars. I'm also confident that EV tech will continue to improve and used EVs will also have high depreciation.

We may well be entering a world where car depreciation starts looking more and more like computer depreciation. This just makes the old FI advice to buy a well used car even stronger. If you really want to profit greenly you should be buying a used car that you expect to be worth about $0 in 6 years time. At that point you can recycle it and have your pick of one of many heavily depreciated EVs.

When my family moved to PA we knew we wanted to generate our own energy with solar panels. We had a lot of evidence that made us think a solar array would be a good investment, even in cloudy central PA. Of course the broad findings of research don't always hold true for every individual. In this post I'll review how our solar system has performed over its first full year and what sort of return on investment (ROI) that gave us. Did our solar panels actually make us money, or were we bleeding out cash to be climate do-gooders?

UPDATE: From Jan to Dec in 2019 our panels generated 11,347 kWh. In 2020 they generated 11,358. Both of these numbers are a bit shy of the 12,700 estimate and it seems safe to say my installer over sold the panels output. SREC prices averaged $35.50 in 2019 and $20.57 in 2020 though. All told in 2019 and 2020 the panels earned $3,513 in tax free money, the equivalent of a 7.3% return on a taxed investment.

How much did we generate?

When you buy a solar system the installer always gives you an estimate of how much you'll generate in a year, but how does that hold up to reality? In our case we bought a solar system that was rated at 10.5 kilowatts (kW). That means that on a perfectly sunny hour the system would generate 10.5 kilowatt hours (kWh) of electricity. It is not perfectly sunny every hour of every day though, and so our installer used average solar radiance for our area to estimate that this system would generate 12,700 kWh each year. In reality though we only generated 10,800 kWh during the first 12 full months our system was operational. Why did this happen and how did it affect our ROI?

The why of it was actually pretty simple, the 2018/2019 year in PA was cloudier than normal. I talked with people who run solar companies and manage thousands of different arrays over the state and they said that they got 10-15% lower generation than normal over that timeframe. Cut 15% off 12,700 and you get almost exactly the 10800 that we generated. I have hope that future years will be less cloudy and we'll hit the full estimate. So far we're on pace to generate 60% more energy this September than we did last year, so I'm hopeful that the clouds of our first year were just outliers.

How much money did we make?

So how much money does 10,800 kWh of solar generation produce in PA? The short answer is $1382. Since this money is all tax free it's the equivalent of a long term investment that returned $1625 before taxes ($1727 if you make a lot of money and pay the higher 20% capital gains tax rate). To understand how these numbers came about you have to know a little about how electricity billing works and a few weird quirks about solar in PA.

Net Metering

First, PA has a net metering law that allows consumers to essentially avoid paying the full retail price of electricity for every kWh they generate. Most states have this, but there are small differences in how it works from state to state. In PA every month someone generates more power than they consume they bank the extra kWhs. Then, in a future month where they use more than they generate they draw the extra kWhs from this bank instead of having to pay for them. Once the bank is empty the consumer has to pay full price for the kWhs. What full price is depends on your utility, the time of year and how much total energy you use but where I live it averages out to about 10.5 cents/kWh. Because of Net Metering we get paid 10.5 cents for almost every kWh we generate, and only get paid at a lower rate if we generate more than we use.

PA's Solar Banking Quirk

The reason I said we only get paid for "almost every kWh we generate" is because of another little quirk in PA's Net Metering law. If a solar homeowner in PA has any extra kWhs banked at the end of May they don't carry over to June and are instead just paid for at a lower rate (we got 6.2 cents/kWh in 2019). This is different than most net metering states where you can just carry over your banked kWh forever. Forcing customers to sell their banked kWhs at the end of May adds a little twist to PA's solar market.

Generally, houses have pretty low electricity consumption in April and May when the weather is nice. At the same time, those months have pretty high solar generation because days are getting longer and the sun is shining a lot. This means that if a solar system is sized to generate 100% of the electricity that home uses then the bank of kWhs that that system builds up will be emptied out during the low generation winter months. The customer will then have to pay retail rate for whatever additional power they use before their panels start generating more than they use again. It took me a while to get my head around this. Maybe a graph will help you sort it out:

Looking at this graph you can see how in the summer we generated more power than we used and built our bank up with this. In October our use and generation were almost the same, and then in the colder months our use was far higher than our generation and we started depleting our bank. In February our bank was gone and we had to pay an electricity bill that was higher than our usual $7 monthly service fee. In March we had our own version of March madness, seeing whether we could generate more than we'd use that month. We came up just short at the buzzer, but have high hopes for success next year. In April and May we started generating more than we used again and built up a bank of around 1200 kWhs. Our utility then paid us 6.2 cents for each of these and zeroed out our bank again the following June.

If our utility didn't force us to zero out our bank in May those 1200 kWhs would have carried over to this year and we would eventually use them to avoid paying the full market rate of 10.5 cents per kwh instead of being paid 6.2. That amounts to all of $50/year so it's not too concerning. But, if you're in PA and want to truly maximize the ROI of your system you should make it small enough that your generation during April and May matches your consumption during those months. As it stands this payout was stored as a credit on our account that can pay for our $7 monthly electric service fee for most of the year.

SRECs in PA

The other quirk of solar in PA is that we have a Solar Renewable Energy Credit (SREC) market. Only a few states and cities like DC, MA, and NJ have SREC markets. Every time you generate 1,000 kWh of solar electricity in one of these states you earn an SREC. Utility companies are required to own a number of SRECs at the end of each year or pay a penalty. Exactly how many SRECs a utility needs to own depends on the law, but in PA it's trying to get solar up to 0.5% of total generation so its not that many. A utility can build their own solar plants to generate the SRECs they need, or they can buy them from others.

When we moved to PA SRECs were selling for something like $9 each and we sold our first batch for $15 each. This was because PA utilities could buy SRECs from pretty much anywhere. This meant that big solar farms in North Carolina were getting most of the SREC payouts and SREC prices were low. During the last year the PA Public Utilities Commission (PUC) clarified a rule on SRECs to state that they had to be generated inside the state of PA to be sold here. This ensures that SREC payouts are driving solar development inside our state and has provided a large bump to SREC prices. After the change we sold one batch for over $40/SREC and averaged over $35 for all of them. Here's a graph of PA SREC prices if you're interested. This amounts to a boost of 3.5-4 cents per kWh, so it really helps ROI. I expect that SREC prices will fall as more solar generation comes online in PA, but I'll enjoy the high prices while I can get them.

What was our total ROI for year 1?

So lets do some quick math and figure out our ROI. We generated 10,800 kWh and avoided paying utility bills for about 10.5 cents for each, so $1134. We lost about $50 of this due to the quirk of our solar bank zeroing out in May, so drop it to $1074. We sold our SRECs for almost $310 total, but only $280 after fees, so bump this up to $1354. We generated 80% of another SREC so we should really add another $28 to this to be fair, bringing it up to $1382. Also note that there are no taxes on SREC income or lowered utility bills. A regular investment would likely pay 15% long term capital gains taxes on its return, so you'd have to earn $1625 in it to take home $1382 after taxes (1625-1625*.15=1381).

PROTIP: Fully max out your ROI by lowering your tax withholding in January and installing near the end of the year. This builds up the tax credit in cash before laying out money to pay for the system, like a free loan. Be sure your installer commits to install the system in a cold month so you don't fail to install that year and run afoul of the tax man.

What about costs? Well, our 10.5 kW system cost $34k to install. The 30% federal tax credit for new solar installations brought this down to $24k. It's important to note that prices vary wildly by location and have been dropping pretty consistently over time. A friend of mine in Virginia got a system installed for over 30% less per watt, while another in CA paid almost 20% more. Rather than try and predict a price for your location I'll just say get a few quotes from a few local installers in your area to see what an array will cost for you.

How Solar Crushes Bonds 

If we had invested this $24k in a bond fund and it gained $1625 before taxes that would be a 6.7% return on investment. This may seem low when comparing to stocks, but solar has next to no risk to this return so it is fairer to compare it to bonds and other "safe" investments. The Vanguard Total Bond ETF (BND) that I use as a safety hedge for my stock investments has only returned more than this ONCE in the last decade. And remember this year's solar radiation was down 15% from expected for us. This ROI could have gone up as high as 7.8% and even higher if SREC prices continue to rise or if we’d found a cheaper installer. In the worst case scenario where it is cloudy forever, and utilities build enough solar plants to drop SREC prices to $0 this would still equate to 5.2% ROI (1074/(1-.15)/24000=0.052) which trounces the 3.8% average annual return of BND.

There is over $200 billion invested in BND right now. There are trillions more invested in other low returning "safe" funds. How many of those investors do you think live in states with net metering and own houses with nice sunny roofs? Are you one of them? Why aren't you transferring as much money from those bonds into solar on your roof as possible? Do you hate money?!? Are you actively trying to drive climate change to flood people out of their homes!?!? WHYYYYYYYYYYYYY?!?!?!?!?!?

What about depreciation?

Okay, things started to get a little out of control there, but I'll catch my breath and talk about the main reason why solar may not be quite as good as the above yelling makes it out to be. The big problem with solar is that the technology just keeps getting better. The efficiency of solar panels has skyrocketed over the years, while the prices to build and install them have fallen. At some point this continuous improvement has to reach a limit, but it's been continuing apace for decades now. It seems possible that in 10 years someone could install a system that generates as much power as my family's does for 1/2 the price.

Does the falling price of solar panels mean that your panels depreciate 50% every 5 years? Not exactly. Even though solar panels are dropping in price, it seems unlikely that utilities are going to drop the rates they charge for power any time soon. Utilities get to basically pass all of their costs onto their customers so while they'll be getting cheaper solar power in the future their customers will still be on the hook for all the coal and gas plants that they'll be decommissioning early because it'll be cheaper to build new solar than to run them.

Yes, if you try to sell your house a savvy buyer will price the panels based on what a new system would cost, but if you just keep owning it the annual return you'll see will likely stay fairly steady. Most solar panels are warrantied to produce 80% of their initial output after 25 years (fancy ones from Sunpower increase this 92%). This means that your annual return will only drop about 0.8% per year (or 0.32%/year for Sunpower). It is also likely that panels you install today will keep producing power decades after their warranties are up. With this in mind I think it's a tough question as to what rate of depreciation should be applied to panels.

Finally, there's the fact that the federal solar tax credit is starting to drop and this will likely more than offset any reductions in panel prices over the next few years. If you get a system installed before the tax credit expires and then sell it shortly afterwards you may even see appreciation from your after tax cost because the buyers will be comparing it against new solar arrays with no tax credit. As time goes on though it is likely that the improvements in solar technology will lead to depreciation for your panels. How much is a tough question. All I can really say is that a solar array will keep producing valuable electricity for a very long time, and that the value of these electricity is what I focus on with my ROI calculations.

Wrap up

After a year's experience with solar panels I am very bullish on them. How bullish? Well, I went and created this website almost explicitly to share this with the world. My family's panels have significantly outperformed the bond fund where we had our money invested in beforehand with less risk. Part of me is sad that I didn't wait for solar technology to improve further so I could get an even higher ROI, but another part is happy that our entire house is being powered by clean solar energy and I'm beating our previous investment already. If you've got a few thousand dollars in some low return investment like Bonds, CDs, or [shudder] a savings account and own a home with a relatively sunny roof you'd be a fool not to look into installing solar. Put some panels on your roof and you too can profit greenly.

Further Reading: Heat pumps pair with solar like peanut butter and jelly. Check out how a heat pump can save you money, how to combine that with solar to go net zero, and why you probably don't need a home battery yet.

My uncle sent me this New Yorker piece about how we should all just give up on fixing climate change. I saw that the author was Jonathon Franzen, and while I couldn't quite put my finger on anything he'd written the name rung a bell and this recognition gave me the initial impression that he must be a smart guy. After reading the article I'm convinced he's an idiot and just the sort of science skimming pessimist that I can live without. He starts out by saying that “we’ve made essentially no progress” on climate when a more accurate statement would be that we have made a ton of progress, but have not yet substantially reduced our total emissions.

What progess you may ask? Well new electric cars can cover distances that were just dreams in the 80's, the top end Tesla S now goes 370 miles between charges. These EVs use less energy per mile than even the most efficient gas cars while having lower maintenance costs and often being faster off the line. As battery prices continue to drop the prices on these cars will too and in the next decade or so we'll reach a moment where an EVs cost substantially less then gas cars. If you appropriately factor in maintenance and fuel we may already be at this point.

EVs already have pretty impressive performance characteristics, and battery tech is the only thing holding them back from completely outperforming gas cars. Once the price and performance advantages of EVs become unavoidable truths the transition to EVs will be extremely rapid. This is because gas stations will start closing as demand for the fuel they sell drops (over 80% of EV charging is done at home). This means as EVs become a higher percentage of cars operating a gas vehicle will just get harder and harder. There may even be EV conversion kits like this one but, actually done cheaply after battery prices continue to fall.

Aside from their efficiency gains these EVs will be powerable by renewable sources and we'll be able to use their batteries to stabilize the grid when renewable generation dips. On top of this we're also in the beginning of electrifying ships and planes as well and as battery tech improves with electric cars these other forms of transit will just become easier to convert. I would call these advances some serious progress!

In terms of the renewable energy transition Franzen is basically silent, outside of opining that building renewables on open land hurts ecosystems. He's right on this, but he also forgets to note how those renewables will replace fossil fuel plants that are already killing far more animals, leading to a net positive in total ecosystem health. He also never notes just how small an area of land will have to be converted to power the entire world. The U.S. has 3.5M square miles of land and it would only take about 21k square miles of solar panels to power us. This seems like a lot, but it's less than 1% of our total land. If you look at that link you'll see many other things that we currently waste far more land on. For example, in 2018 the US used 33k square miles to grow corn for ethanol that replaced less then 10% of our total oil consumption. Turn 2/3s of that corn into solar panels and you power literally our entire country! Better yet use that area to grow actual food and cover some marginal land in panels. This all seems like massive progress that should give people who know about it hope, but Franzen either hasn't yet read about it or is willfully omitting it from his essay.

Franzen does note that "carbon emissions from existing global infrastructure, if operated through its normal lifetime, will exceed our entire emissions “allowance"". This is also true, but pessimistic and economically unsound in its assumption that we'll run all of these old plants on fossil fuels through their full normal lifetimes. Utility scale solar and wind are now pretty much always cheaper to build new than new coal/nuclear plants and often cheaper than new gas plants. The prices of renewable energy generation have dropped over an order of magnitude since the 1980s and will likely keep dropping in the future. Here's a post from 2014 with good graphs on solar prices, the price dropping trend lines they show have continued through 2018. When it is cheaper to build new solar than to run existing fossil fuel plants they will be shuttered before their end of life. We've already seen this happen with tons of new gas plants replacing coal plants coal plants and it won't surprise me when the same thing happens to those gas plants.

Renewable generation capacity worldwide has quadrupled in the last decade and in 2018 it accounted for 12.9% of total capacity, up from 11.6% in 2017. If this 1.3% increase continues every year then in 66 years we'll be at 100% renewable generation. Of course it is unlikely that this rate will just stay at 1.3%, it's actually been increasing over time. There will be some pressure to slow down on renewables when they make up a larger share of the grid because it makes grid management more difficult, but there will also be pressure to deploy more as their prices continue to fall. As energy storage to handle renewable generation's intermittence also becomes cheaper we will see grid management issues reduce and renewable deployment grow even more, heck solar+battery systems are already beating out gas peaker plants on price. 

The fact that renewable technology has gotten so cheap is remarkable and honestly fairly lucky. If we lived in a world where renewable energy still cost 2-10x more than fossil fuel energy then I might share Franzen's pessimism. But, due to the hard work of lots of people and some lucky truths of physics this is not the case. Yes, we need governments to help speed our transition to renewable technology, but it is not as bleak as Franzen suggests.

One big step would be to simply put a price on carbon. To avoid the revolts against government interference that Franzen predicts you could take the money that this tax pulls in and refund it equally amongst all tax payers. This is essentially what the Energy Innovation and Carbon Dividend Act does and there are other similar ideas both in the US and abroad. Are people really going to revolt when the government starts sending them checks every month? Or are they instead going to shift their consumption to cheaper, lower carbon alternatives and try and be one of the majority of people who will gain more from that check than the spend on the tax (it's a majority because the top 1% of users emit so much carbon that well over 50% of all people use less than average).

On top of this Franzen is also flat out wrong about a lot of climate science. The 2°C limit is not about a tipping point at which we're sure that runaway warming will occur, it's a point at which we're confident that life will become far worse for people and ecosystems on this planet.

Franzen says "If you’re younger than sixty, you have a good chance of witnessing the radical destabilization of life on earth—massive crop failures, apocalyptic fires, imploding economies, epic flooding, hundreds of millions of refugees fleeing regions made uninhabitable by extreme heat or permanent drought. If you’re under thirty, you’re all but guaranteed to witness it." But even the IPCC's worst projection (RCP 8.5 where emissions just keep on rising) doesn't put us above 2°C for another 40 years and it will take years of being at 2°C before the environment really gets ugly. Does Franzen not know the average life expectancy in the U.S.?

It's also very likely that we'll do better than the doomsday RCP 8.5 scenario. As I outlined above I think tech advances make this economically unlikely. The next 10-20 years will really tell, but if the renewable and battery price trends continue I think we'll see dropping emissions and be well below RCP 8.5. Whether we drop fast enough is a good question. It's also a good question whether some of feedback loops that we're afraid of actually materialize. But lets give it 10-20 more years before we just give up. Even if we do lose the fight it's unlikely that anyone reading this will actually be alive long enough to see the worst of it, but some descendants of our might and we owe it to them to work as hard as we can right now to avoid the worst.

UPDATE: After living in my house for a couple more years I can attest that the heat pump has handled each winter flawlessly. In 2019 it used a total of 4,375 kWh (around $300 worth of solar energy) to heat and cool my home and in 2020 it used 5,106 (around $350). Check out this thread to see why my use increased. Coincidentally 5,106 is the exact amount of energy my resistance hot water heater is estimated to use in a year. Maybe I should upgrade it.

After one year we have ended up only spending $477 total to power our heat pump for both heating and cooling. This low $477 annual HVAC spend assumes we pay 10.5 cents per kwh like our neighbors do. In reality though our solar panel system gives us electricity for less than this. I like to calculate that price difference as part of the solar ROI and leave heat pump ROI based on the 10.5 cents all our neighbors pay for power. The estimate for how many kWh's our heat pump uses comes right from our Bryant thermostat display. I've compared the thermostat's numbers to our total monthly electricity bills to double check it and it seems about right. It also nicely breaks down the estimate based on how it is using the energy, and if you write down the totals every month you can make a nice graph of them all.

Looking at this graph you'll notice a few things immediately. First off, we didn't turn our heat pump on a single time during the month of September. This is because the weather here in central PA was very nice that month. Opening our windows at the right times and wearing the right clothing was all it took for us to be comfortable all month long. I was hoping that May and June would be the same, but as you can see we did use a tiny bit of electricity on heating and cooling during those months. Maybe we're just getting weak in our old age?

Next off, you'll see that we use far more electricity for heating than for cooling and it has a big spike in January. This spike contains a significant amount of "resistive heat" which comes from old style heating coils like the kind that glow in a toaster. When the outside air gets cold enough that the heat pump alone can't maintain the thermostat's set temperature these turn on. Getting heat out of these coils can take 4 times as much electricity than it would take to produce the same heat from a heat pump. As the temperature drops a heat pumps efficiency drops as well, so when its really cold out resistive heat coils may only use twice as much electricity to produce the same amount of heat, but you still want to avoid running them as much as you can.

The above graph shows that while the resistive heat is a significant portion of our total energy use in January it wasn't all that bad, only about 1/4 of the total electricity we used to heat during that month. This means resistive heat produced somewhere between 1/8th and 1/16th of the total BTUs of heat we used that month. I'd say a "bad" heat pump would be one that puts more energy into resistive heat coils than the heat pump during a cold month. What is "bad" of course depends on how cold a "cold month" in your area really is and it's still important to compare this to how much the unit costs to install. What may be a "bad" heat pump in Pennsylvania might be a great heat pump in Florida.

The Key Metric To Look For In A Heat Pump

When looking at heat pumps there are are few key things to look at. First, and most obviously is the price of the unit. After this you can look at something called the HSPF, which tells you roughly how efficient the heat pump will be over a season. The problem with HSPF is that the weather you have is likely different than the weather HSPF was calculated for. If you live in a cold place like central PA I recommend looking at how many BTUs the unit puts out at 47F and at 17F. Any reputable heat pump should have ah AHRI certification with this information.

Our Bryant unit is rated at 33.4k BTUs at 47F and 31.6K BTUs at 17F which is a nice small drop. I've seen a similarly priced Lennox model that produces 32.2k BTUs at 47F but drops way down to just 21k BTUs at 17F. It will use resistive heat to pump out the 11.2k of BTUs the heat pump can no longer generate when the outside air is 17F. As I explained above resistive heat is so much less efficient than a heat pump use 2-4 times as much electricity to produce the same amount of heat. This means that the resistive heat elements in this Lennox unit can use up to twice the electricity as its heat pump when temps drop very low. Imagine if the orange top to my red bar in January was twice as thick as the red bar below it and you start to understand why I call heat pumps like this "bad" for climates like Pennsylvania.

What About A Ground Source Heat Pump?

One way to avoid the low 17F performance issue entirely is to buy a ground source heat pump instead of an air source one. These take heat from a fluid that runs through a pipe buried underground rather than the outside air. Since the ground has a pretty stable temperature once you get down far enough these units perform about the same no matter what the outside air temperature is. The other good thing about ground source heat pumps is that since they are located inside your home they never need to run a deicing cycle like an air source unit does. These cycles use energy and can sound like someone running a small chainsaw outside your house (though they only run on the coldest days when you're unlikely to be outside).

The problem with ground source is that burying a long pipe deep in the ground is pretty dang expensive. It can easily add $10k to the installation cost of your installation. As I mentioned above I spent less than $500 running my air source heat pump last year. A ground source unit will probably only use 10-20% less energy than my unit so I could save at most $100/year.

If you invested $10k in a CD with a 1.5% interest rate it would return $150/year so a ground source heat pump would essentially never beat even a very low returning investment like a CD. If pipe installation costs are much lower where you are, or you live in a much colder area (like say, Canada) then it might make sense. But, for most of America I think that air source units have gotten so good that ground source heat pumps should be ignored.

How Much Did The Heat Pump Save In A Year?

I started out noting that we spent only $477 to power our heat pump last year, but how much did this save us? Since we had the heat pump installed before we moved in we can't answer this for sure. A home energy audit we had done before we moved in estimated that it would cost $1,756/year to heat and cool our 2,000 square foot house with it's old oil furnace and AC. By that estimate we're saving $1279/year. But, it was using the average American's thermostat settings, which are far higher than our own. We set our thermostat lower in winter (65) and higher in summer (79) and do some other tricks like opening our windows at the right moments during the day to save more energy. Taking this into account and looking at our heat pumps data I think we saved more like $1,000 this last year, or around $83 per month.

What's the total ROI?

To calculate the total ROI you need to compare the up front install cost to the monthly savings. Our high efficiency heat pump had a total install cost of around $15k after rebates. This seems like a lot, but based on the age of the furnace and AC we were going to have to replace them anyways. The median install cost for a new furnace in PA is $4500 while an AC is $4700. That's over $9k right there. Of course, given how little we use the AC we could probably have gotten away with just using a few cheaper window units instead of a whole house setup. Still it seems unlikely that we could have replaced both for under $5k total. That means that our heat pump cost at most $10k extra. If I invested this $10k in some stock/bond/CD that earned 6% each year then after 15 years I'd have $23,965. If instead I invest the $83.33 I save each month in the same stock/bond/CD that earns 6% each year then after 15 years I'd have $23,275. These are pretty close, and if you're paying taxes on your capital gains then the $83.33/month heat pump actually wins because with it you are only paying taxes on $8,275 worth of gains, instead of $13,965 (at our current 15% long term capital gains rates this amounts to $853 more in taxes).

The take away from all the numbers above is that if my investments return less than 6% per year then I am better off having paid extra for my high efficiency heat pump and if my investments return more than 6% then I'm losing. If you look at the return of the S&P 500 you'll see many recent years where it returned over 10% and maybe you'll think that a heat pump is a bad investment. If you go back further you'll also see years where it dropped, 10, 20, even 30%. This volatility is why people diversify their portfolios with safer, lower returning assets like bonds. If you look at the returns of a bond index you'll see them only returning over 6% a few times over the years. The return from this high efficiency heat pump is both more stable than the return from bonds and higher, what's not to love?

In the end the exact math on this will depend on the weather where you live, the sort of house you live in, the price you pay for power and your personal thermostat habits. Run the numbers yourself (or leave them in a comment here and I'll try to help) and see what sort of return you'll get on your own heat pump. If you're the sort of person that wants safe investments in your portfolio then you should definitely consider shifting money from those investments into a high efficiency heat pump when your current HVAC nears the end of its life. If you're a risk taker who owns all stocks then you should compare current mortgage interest rates (around 4% as I write this) to the return you'd get from upgrading to a heat pump. You'll probably find that expanding your mortgage to include the price of a new heat pump will actually lower your monthly payments. Whatever you do, I hope the real world numbers and analysis I've provided in this article can help you to profit greenly yourself.

An Aside on Gas Furnaces

In this post I compare the price of a heat pump to an oil furnace. Per unit of energy natural gas currently costs about half of what oil does. A gas furnace can also be installed quite cheaply if you're willing to DIY. One thing you will face with a gas furnace is a gas connection charge of around $15/month. You'll have to pay this all year round, even in the summer months when you are using next to no gas.

I ran the numbers for gas service I had at an old house in upstate NY and the monthly connection fee increased the cost per ccf of gas by nearly 35%! This was for an annual gas use of nearly 550 ccf, which I consider fairly high. If you are in a warmer state, or have a better insulated/air sealed home and use less than this then the % price increase will be even higher. For example, if I'd used only 200 ccf per year then the monthly usage fee would have nearly doubled my cost per ccf. In that case shutting off gas to my house and going all electric could allow a heat pump to provide a higher ROI than gas.

Further Reading: Now that you've learned a bit about heat pumps, check out my post on Solar Panels then put it all together with my post on Going Net Zero