Cutting noise levels
We were all impressed by how quiet the mowers were. It’s certainly admirable to reduce air pollution, but it’s also nice to cut down on neighbourhood noise pollution. In terms of noise output, the range went from a low of just under 81 decibels to just over 88. The noise was measured 5' from the ground in the operator’s position. These numbers compare very favourably with my old gas guzzler, which pumped out over 92 decibels, and my household vacuum cleaner, which was louder than two of the machines at just over 84 decibels. You could almost talk over the quietest machines, and you could definitely hear your spouse calling you from the house.
Safety features
All of the machines have built-in safety devices to prevent inadvertently activating the blades. There are a few different systems, and they all require gripping a safety handle or lever to start the mower and keep it running. In addition to this feature, some machines also require a key to be inserted before the mower can start. The key also functions as a lockout for servicing: before tipping the mower over or in order to prevent children from starting it, you pull the key from its slot. One machine, the Solaris, emits a high-pitched warning tone from the moment its batteries are engaged until you start it up.
Different strokes
Believe it or not, your leisurely weekend chores could be contributing to local air pollution and global climate change. A typical gas-powered lawn mower emits almost 40 kg of greenhouse-gas emissions a year. And older two-strokes—the kind for which you have to mix oil with the gasoline—are the worst offenders. According to Environment Canada, a two-stroke lawnmower pollutes as much as 40 (yes, four-zero) late-model cars running for the same amount of time.
Two-strokes pack a one-two punch: the oil-fuel mixture is inherently dirty, and the relatively simple design allows a bit of unburned fuel to leak out the exhaust port with every revolution of the piston. (If you’ve ever used an old outboard two-stroke, you’ll likely have seen the oily shimmer that the engine leaves in its wake.)
The more complex (and, therefore, bulkier and costlier) four-stroke design is significantly cleaner; yet, either way, the fuel itself is also problematic, with hydrocarbons entering the atmosphere from spills and evaporation.
If you’re interested in greening up your yardwork, the Clean Air Foundation teams up with Home Depot every spring to get gas-powered mowers and trimmers out of circulation. The equipment is recycled and you get a $100 credit toward a new push or electric mower. So far in 2008, the program has collected more than 8,000 gas garden tools. —Allan Britnell
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