Electric Lawn Tools Rule
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.
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.
Incredibly janky port of comments from my old WordPress site:
2021-11-10 at 9:58 pm
We just moved and our 0.8-acre urban homestead in the making was too much for my beloved Fiskars reel mower and corded string trimmer. I’m committed to owning only the one engine in our van, so this article was very helpful in navigating the battery tool options. I’d intended on getting the Kobalt 40V mower, but they have been unavailable for months, so I ended up with the Ego 56V (bought at full retail…my grass was knee-high!). It powers through tall wet grass at least as well as a gas mower. I’ve since added a string trimmer and hedge clippers. Acme tools sells refurbished Ego tools with batteries for the retail price of just the batteries. With a 5ah and two 2.5ah batteries, I can now mow continuously, at least enough to finish the yard.
Incredibly janky port of comments from my old WordPress site:
2021-04-28 at 3:04 am
This is so well written up, thank you for the analysis. I just wanted to chime in with our reel mower experience and a couple of points you may not have considered.
One easy way I like to do research is to find the most expensive product in a category and analyze it very carefully to see what features it has (I only look at functional features not like “dipped in gold” or anything). For lawn mowers in general, not just reel, I believe the state of the art would have to be Swardman: https://www.swardman.com/en/electra-55-reel-mower/ These things run upwards of $3000! Their claim is that if you cut grass with a reel rather than a more common blade, it clips the grass in a way that’s healthier for it and the general lawn ecosystem. Since I never believe marketing I dug around and it does look like golf courses use reel mowers for precise and healthy cuts, and that in general people agree reels are better. With that in mind, we looked for an electric reel mower that didn’t require us to get a second mortgage, and found a couple. But with limited options we found short battery lives and reports of “what’s the point, just push it yourself”.
And so that’s what we did, we tried two push mowers. One was Fiskar’s top of the line: https://www.fiskars.com/en-us/gardening-and-yard-care/products/reel-mowers/staysharp-max-reel-mower-362050-1002 and another was Gardena’s pricey but not fancy alternative: https://www.gardena.com/int/products/lawn-care/cylinder-lawnmowers/classic-cylinder-lawnmower-400/967302501
We used the Fiskar for a couple years on a small lawn and loved it. But it is VERY heavy. The Gardena is a welcome replacement on our larger lawn. We mow our front and back yard, probably somewhere around ~4000 sq. ft., in about 40 minutes or so. I’m not in stellar shape and I don’t really get exhausted doing it, but it’s work. On hot days I definitely sweat a bunch, and if I run instead of walk, I’m gasping by the end of it. So this is my second point: I actually *like* that it makes me move and gets my heart rate up a bit. We’re way too sedentary these days, I’ve learned to appreciate any way I can trick myself into moving some more.