It's better to heat your home with gas than with wood.

It's better to heat your home with gas than with wood.

It's better to heat your home with gas than with wood.

Illuminating answers to environmental questions.
Nov. 11 2008 7:30 AM

Wood, I Wouldn't

It's better to heat your home with gas than with trees.

I live in a fairly rural place, and we have an oil furnace, some electric heat, and a wood stove. I've heard that wood burns pretty cleanly, but it doesn't look like it compared with what comes out of the oil-furnace chimney. Of course, wood doesn't have to be refined, and it comes from only a few dozen miles away. It's getting chilly: Should I be heating my home with firewood?

Wood-burning stoves. Click image to expand.
How green are wood-burning stoves?

It's not just old-timey nostalgics who are mulling this question. Sales of wood stoves are up 55 percent over last season as consumers look for a greener and a cheaper alternative to oil and gas.

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So how does the green case for wood stack up? The argument centers on the fact that wood is a renewable resource: When you chop down a tree for firewood, you can easily plant one to replace it. (It would take millions of years to replace spent fossil fuel.) Mile for mile, transporting firewood can be pretty energy-intensive since it's so bulky, but you are far more likely to have wood in your backyard (literally!) than you are to be located in close proximity to natural gas reserves.

But a "burn local" movement won't do much to help the environment if your stove starts spitting out toxic fumes. In some communities, wood smoke accounts for as much as 82 percent of particulate matter—tiny particles that can cause serious respiratory problems—emitted during the winter. Moreover, because that smoke is being produced right in (or outside) your house, the probability of exposure is greater—and that can have significant health effects. Existing research suggests that young children living in homes heated by wood-burning stoves "had a greater occurrence of moderate and severe chronic respiratory symptoms" than children in homes without those stoves. And it's not just that these particulates might be hard on your lungs: Wood smoke has high concentrations of toxic chemicals like benzene, formaldehyde, and polycyclic aromatic hydrocarbons, all of which are considered possible carcinogens by the Centers for Disease Control and Prevention.

The good news is that the most modern stoves—which must be manufactured under EPA requirements—are a good deal cleaner than the old models. But while the new versions cut down on emissions by more than two-thirds, they can still produce particulate matter concentrations about 100 times greater than oil or gas furnaces. And outdoor wood boilers—which have become more popular in recent years—are typically even bigger emitters than stoves.

What about greenhouse gases? All in all, using wood to heat your home is generally considered to cut down on the emissions that cause global warming. There's some debate about how to figure the carbon footprint of burning wood: After all, a tree releases carbon when it decomposes anyway, so it's conceivable that putting wood in the stove is more or less carbon-neutral. On the other hand, if we cut down trees faster than they are replaced, there's a net reduction in carbon sinks that sequester carbon dioxide. And when a tree decomposes, some of that carbon is absorbed by the soil; when you burn wood, virtually all of it will end up in the atmosphere. Still, as long as your firewood is farmed sustainably, heating by wood is less likely to contribute to heating the earth. Researchers estimate that, in total, wood may produce between three times and 10 times fewer greenhouse gas emissions per unit of heat than other energy sources.

So, is wood worth it? Taking everything into account, the Lantern doesn't recommend switching over to wood for environmental reasons. If you want to cut down on your greenhouse gas emissions, there are better ways of doing it—from changing your transportation habits to your diet—that won't involve pumping those other pollutants into the air. Instead of changing your source of fuel, you may want to think about how you might get by with less heat to begin with; to start, you can turn down the thermostat by a few degrees or improve your insulation.

Of course, if memories of the hearth or a surplus of kindling have driven you to a wood burner, make sure you're using an EPA-certified stove manufactured after 1992 to cut down on your particulate emissions. (For other tips on how to use a wood stove in a greener way, this is a good source.) After all, where there's fire, there will be smoke—but it doesn't have to be quite as bad for the environment as it used to be.

Is there an environmental quandary that's been keeping you up at night? Send it to ask.the.lantern@gmail.com, and check this space every Tuesday.

Jacob Leibenluft is a writer from Washington, D.C.