Hey Mr. Green,
If I scavenge firewood instead of buying it, is it better to heat my house by burning wood in my fireplace or by using electricity from traditional sources? --Joyce in Charleston, South Carolina
Perfect question for this time of year. If you start thinking about heating during the summer, you can get your act together in time to upgrade your system before winter. Sure, this sounds like that goody-goody little ant in Aesop’s fable, working his exoskeleton off while the grasshopper frolicked around the fields, but it’s true.
First, don't burn wood very often unless you have an EPA-approved fireplace box or stove. Depending on the local climate and terrain, a wood fire can be a dangerously polluting proposition, which is why some towns have banned it. It can be especially harmful in regions with high levels of soot, or “particulate matter” pollution. Too much of it can damage lungs and circulatory systems, and according to the American Lung Association, woodstoves and fireplaces account for much as 80 percent of this pollution in some areas during the winter. (You can find real-time information about your city’s air quality and more information about particle pollution at airnow.gov.)
Burning wood gives off chemicals as nasty as some of those concocted in factories, including sulfur dioxide, formaldehyde, and dioxin. With older (or poorly maintained) fireplaces, a lot of these poisons can stay right inside your house. It’s not going to hurt you as much as wood fires did poor Oetzi the Iceman--after his 5,000-year-old frozen corpse was found in the Alps, the autopsy revealed lungs as black as a chain-smoker’s, probably because he spent so much time around open fires--but why take chances?
Environmentally, scavenged wood is all right as long as it wasn't painted or treated, in which case burning it would release additional dangerous substances like, say, arsenic. If you're scavenging from a forest or woodlot, though, don't hog all the deadwood. Healthy forests need it to feed bugs and other critters that are important in the food chain of forest ecology. Imagine you're a hungry woodpecker, and you’ll understand.
Electric heating offers a cleaner option because power plants can control emissions better than your fireplace or stove can. But electric heating is rather inefficient and not the best choice in the grand scheme of things. This is because a lot of the original energy (roughly 60 percent) in coal or natural gas can be lost when it is burned to create steam to run the dynamos to generate electricity. By comparison, even the least efficient of the new furnaces are 80 percent efficient, and some are as high as 95 percent efficient.