There are two simple things one can do to change energy use in their home.
Cordless Mower
Buying a cordless lawnmower is a great idea if you want to cut down on the noise and pollution when cutting your lawn. Last summer I bought a Yardworks 24V 3-in-1 cordless mower, the 20″ size. It’s called 3-in-1 because you can use it in mulching mode, with side-chute, or with rear bag to catch the grass clippings. It cost about $450, taxes included, but so what. It does the job handily.
Beforehand, I looked at the different models of cordless mower and after a bit of research I narrowed it down to two brands: this one and a Black and Decker model. I chose this one because, unlike the Black and Decker, it has a metal frame (not a plastic one) and you can remove the battery. This is ideal because you can store the battery indoors in the winter, which is important because cold temperature can shorten the life of the battery, which is lead-acid in this case.
The mower works great for our size of property – which amounts to about 30-45 minutes of cutting time. As it turns out it can cut the lawn with just enough charge to spare, as shown on the charge indicator.
The figures below show pictures of the cordless mower.
A replacement battery is about $100. But if you follow the instructions, like charging it before and after every use, and every two weeks when not in use, then it should last you for several years. It’s not too different from a cordless drill battery.
It takes about 15 hours to charge from a full discharge and unlike some other battery types, you don’t have to fully discharge it before charging it again. But the battery is a bit heavy, around 30 lbs. The overall weight of the mower is 80 lbs so it does weigh a bit more than a gas mower. But I personally didn’t notice it that much, given that my lawn is on flat terrain.
The power is good. The blade rotates at 3500 rpm and doesn’t slow appreciably except with grass that hasn’t been cut in 2-3 weeks. In that case just cut a narrower swath and you’ll be fine.
You don’t need to change any oil. Just keep it reasonably clean, and be careful if you decide to clean it with a water hose (on top and underneath). You don’t want water getting into the motor. Treat it like an ordinary electric power tool.
It only costs me about 10 cents to fully charge the battery. So do the math, you might be paying $1-2 each summer for electricity. But admittedly, if you factor in the battery replacement cost every few years then the cost of gas vs. electric would probably be comparable.
The figure below shows a charge versus time graph for the battery. This was done using a “watts up?” power analyzer. It collects data points on power consumption, which you can then import into a spreadsheet and plot. Very handy.
On one charge from a fully discharged state, the total electrical energy input was 700 Watt-hours, which is equal to around 10 cents per charge given a utility rate of about 15 cents/kWh.
Here’s a summary of the good points to make about this particular cordless mower:
• good power level for grass that isn’t too high
• it’s somewhat noisy but not as loud as a gas-powered mower
• able to cut our whole lawn on one charge
• maintains motor speed throughout as the battery drains
• no oil changes necessary – cleaner system
• the battery is removable
• no maintenance other than charging the battery and proper storage
• no pollution, and not breathing in exhaust fumes
• easy to turn off and on when you have to move something out of the way when cutting – very convenient. Starting is a relative snap compared to a gas mower – just press a button
• when you turn it over to clean there is no concern with oil getting into the engine
• because the battery is removable it can always be replaced with a better battery as the technology develops
Another positive to consider, which doesn’t apply to my mower (but it does to some of the higher end models), is that you can completely avoid using power from the grid in order to charge the battery. You attach a solar panel, which comes as an accessory, to the battery and that does the charging. And given that you generally only cut the grass once a week (or two), that allows plenty of time to charge the battery. But personally I would rather have a general-purpose solar panel, not just one that’s designed for the mower battery. This way you can use it for different charging purposes.
So here you have all these positives … but just to play devil’s advocate, what if I had been using a cordless lawnmower all along and a “new” gas model came along. Would I switch to gas? Is the novelty factor weighing into my decision? Well, there’s two main positives that I can think of with the gas mower which outweigh the cordless mower advantage:
• more power
• less weight
However, the clear disadvantages of a gas mower are:
• have to buy gas and oil
• have to change the oil regularly
• it’s noisier
• it pollutes
Now compare these to the clear disadvantages of the electric mower:
• heavier
• somewhat less power
• battery charge may be insufficient for larger lawns
• battery needs replacement every few years and they are somewhat expensive
I think if I was a contrarian at heart I would find at least as much reason to dislike a gas mower as I would an electric mower, based on the above points. All things to consider of course. But I personally think that, for the electric mower, the disadvantages are growing pains until they either don’t bother you anymore or the technology finds a way to deal with them.
Low Energy Light Bulbs
This is a no-brainer. Low energy bulbs use less electricity which means you pay less hydro. The ones we have in the house use about 14 Watts, and they last much longer than incandescent bulbs.
Just make sure that if you put them outside they are rated to be able to withstand cold winter temperatures, if necessary.
