July 2010
A Greener Way to Trim a Lawn
Lawn mowers and other gas-powered lawn equipment may keep yards tidy but their small engines emit a surprisingly large amount of pollution. By some U.S. Environmental Protection Agency (EPA) estimates, engines used to maintain lawns and gardens account for 5 percent of total U.S. air pollution.
Although regulation of small engines has not been a governmental priority, new rules will go into effect in the next year or two governing emissions from small engines.
The gasoline engines powering lawnmowers and other yard equipment emit carbon monoxide, a colorless and odorless gas toxic to humans. They also emit hydrocarbons and nitrogen oxide that contribute to the formation of ground-level ozone. Operating a gasoline-powered lawnmower for one hour produces the same amount of smog-forming hydrocarbons as driving an average car almost 200 miles, according to the EPA.
What’s more, gas lawnmowers are noisy—just ask anyone who wanted to sleep in on a Saturday morning when a neighbor decided to do yard work.
Options exist to help keep grass beautifully groomed while reducing air and noise pollution.
A manual reel mower is one great option. These mowers have no engine, no fuel, and use human power. They have zero emissions and emit little noise. A reel mower’s cost starts at $70. To maximize their effectiveness the blades should be sharpened regularly and wheels lubricated. Though it’s still hard to push a reel mower through tall grass, today’s models are lighter and easier to maneuver. They are best-suited for smaller yards.
Electric- and battery-powered mowers offer a clean alternative to the reel mower. Like gas mowers, electric- and battery-operated mowers have a motor that spins a blade, which cuts the grass. They are quiet, emit no direct pollutants, and can either be corded or cordless.
Costs for a corded mower are similar to that of a gas-powered mower, ranging from $150 to more than $400. However, they do have one very limiting feature: they must be connected to the house via an extension cord. Users must be aware of where the cord is at all times to avoid running over it with the mower.
Cordless rechargeable mowers are more convenient than their corded counterparts. Some cordless mowers have a removable battery that can be charged inside the home and placed in the mower when it is time to mow. Costs range from $200 to more than $500.
Rechargeable mowers are limited by the life of the battery pack. As a result they may not be best for large lawns. When shopping for a cordless mower, look for information on the size of lawn the mower can handle or the minutes the mower runs on a single charge. Many cordless mowers sport claims of being able to cut one-third to one-half acre of yard in 45–60 minutes. Actual times will vary, depending on the battery’s age, grass height and energy of the user.
The choice in cordless mowers has expanded, with models introduced by well-established companies like Toro and Black & Decker as well as newcomers like Neuton. But cordless mowers receive mixed reviews. Given the high cost of the mowers, careful attention should be paid to the brand and model. Online reviews of cordless mowers are a helpful resource.
Brian Sloboda is a program manager specializing in energy efficiency for the Cooperative Research Network.