Electric vs. gas lawnmowers: Which is cheaper?

Saving Pennies or Dollars is a new semi-regular series on The Simple Dollar, inspired by a great discussion on The Simple Dollar’s Facebook page concerning frugal tactics that might not really save that much money. I’m going to take some of the scenarios described by the readers there and try to break down the numbers to see if the savings is really worth the time invested.

Matthew writes in: Electric vs gas lawnmowing

This is an interesting issue because one of our neighbors uses an electric lawnmower for her yard. We use a gas mower. Thus, for these calculations, I looked at data for several different electric mowers and used numbers from our own mower for comparison.

Initial cost The initial cost of electric and gas mowers both vary widely for various reasons, usually related to engine size and the width of the mower. Generally, gas-powered mowers seem to be about $50 less expensive for comparable features.

Cost per mowing A typical electric mower can mow about a third of an acre with a single charge. A typical pushed electric mower requires about 3.5 kilowatts to recharge, and with an electriciy rate of about $0.11 per kilowatt hour, that’s about $0.38 per recharge.

As with electric mowers, there’s some variability in gas mowers. Our push mower is pretty typical. We can mow about half an acre on a single tank, and our tank is about 2/3 gallon. At a price of $3.50 per gallon, that’s about $2.35 for a single mowing.

Per acre, you can use an electric mower for $1.04. You can use a gas mower for about $4.70. How much of an impact this has depends heavily on the size of your yard. The larger your yard, the more worthwhile the electric mower will be.

Time per recharge Here’s where the “catch” is with electric mowers. Once you’re out of charge, you have to spend 12 hours (or so) with the mower attached to an outlet in order to recharge the engine. On the other hand, if you run out of fuel with a gas-powered mower, you simply add more fuel and restart.

Of course, with some electric mowers, you do have the option of simply buying a replacement battery, keeping the replacement charged, and swapping batteries if one of them runs out. This requires a mower with a replaceable battery, the extra cost of the second battery, and the initiative to keep both batteries charged up.

Yes, there are also some mowers that actually stay plugged in as you mow, but the cord hassle with those mowers – and the fear of what might happen if I cut that cord – would keep me from ever owning one.

So, which is the better deal? From my perspective, if you have a tiny yard (0.1 acres or less), it’s going to take a very long time for the energy savings for the electric mower to catch up to the initial savings on the gas-powered mower. Similarly, if your yard is larger than a single charge of the electric mower than cover, the hassle probably won’t be worth it.

The sweet spot is when you have a yard that begins to approach the size that a fully charged electric mower can cover – say, 1/3 of an acre. You’re going to be using the mower enough that the savings on energy use will quickly add up over time and eventually overtake the initial extra cost of buying an electric mower.

Simply put, if you have a tiny yard (0.1 acres or less) or a big yard (much over 0.5 acres), a gas mower will save you money. Otherwise, an electric mower is probably the better deal.