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10 Tips for Burning Firewood Responsibly


10 Tips for Burning Firewood Responsibly

By Jeff Serena

The renewed popularity of firewood as a fuel for home heating in the United States is raising some legitimate concerns about air pollution. The basic problem is that woodstoves don't completely burn all of the wood that we put into them. If they did, woodstoves would only produce heat, light, water vapor, and carbon dioxide—and only the amount of carbon dioxide that the wood would release anyway if left to rot on the ground. With incomplete burning, however, we also get noxious pollutants like carbon monoxide, various nitrogen oxides and hydrocarbons, and, perhaps most importantly, microscopic particles of wood tar, soot, and ash—smoke. Responsible wood heat means burning wood as completely as possible to reduce emissions of potentially harmful pollutants. Here are some ways to do that.

1. Burn wood in an EPA-certified woodstove or fireplace insert. Since 1992, woodstoves and inserts sold in the United States have incorporated technology that reduces emissions by burning much of the smoke before it gets into your chimney, either by means of a secondary combustion chamber or, less frequently, a catalytic combustor. This technology not only reduces emissions, but greatly improves the efficiency of the stove in converting firewood into heat, so you need less wood to heat your home. As an added bonus, the reduction in smoke output will keep your chimney cleaner, reducing the risk of a potentially dangerous chimney fire. If you're burning in an old woodstove, look into replacing it with a modern appliance. If you're shopping for a new stove, try to find one with an efficiency rating of 70 percent or higher and an emissions rate of 3.5 grams per hour or less.

2. Have your chimney inspected before having any new stove professionally installed. Bad woodstove installations and poor chimney linings are just plain dangerous.

3. Don't try to heat your home by burning in an open fireplace. Fireplace fires look nice, but they're hugely inefficient, typically losing 70 to 90 percent of the heat up the chimney. Besides, they throw sparks and trash the air outside the house—and often the air inside the house too.

4. Don't burn in a thirty-five-to-one firewood burner. These burners look like real woodstoves, but they dodge the EPA regs by having virtually unregulated airflow into the firebox, making them the equivalent of an open fireplace. That's bad. Lots of pollution and little heat.

5. Don't burn wet wood. Wet wood dramatically reduces the efficiency of your woodstove and throws a lot of smoke. Whether you buy your wood cut and split, have logs delivered, or fell your own trees, do it early (or even the year before) so the wood has time to dry. Stack the wood off the ground in a place that gets direct sunlight and good air circulation. In wet or humid climates, cover the top of the stack to keep the rain off. Properly dried firewood should have no more than 25 percent moisture by weight, and 15 to 20 percent is better.

6. Don't burn anything in your stove except untreated wood and a little plain newspaper to help get the fire going. No pressure-treated lumber scraps, painted wood, plastic, old magazines, junk mail, notifications of property tax increases, or other trash.

7. Stage your firewood indoors. Find a sufficient space in your home to stack two or more days' supply of firewood within reasonable distance of your woodstove or insert. There are some nice racks made for the purpose, or you can build your own. Holding a small amount of wood inside warms and dries the wood a bit (making ignition faster and easier and cutting down on smoke), adds a little moisture to the dry winter air in your house, and keeps you from having to open the door and go outside repeatedly to bring wood inside five sticks at a time. People worry about bringing in termites or such, but if your wood was stacked and dried properly, there's no significant threat of imported pests.

The smoke emerging from these chimneys means the homes' residents aren't burning their fires hot enough.

smoking chimney

8. Don't let the fire smolder. Either build a real fire or let it go out. If you see smoke coming out of your chimney, you're not burning hot enough, and you need to add fuel or air or both. One spring a few years ago, a neighbor looked at my depleted woodpile and unwittingly paid me the highest compliment you can give a firewood burner: "When do you burn all that wood? I never see smoke coming out of your chimney." Exactly.

9. Watch for creosote build-up in your woodstove. Most modern woodstoves have a nice window so you can watch the fire. It's cozy and romantic, and it's also a coal-mine canary. If the window is collecting dark brown deposits from creosote (the tarry footprint of incompletely burned wood) it's a dead giveaway that your chimney and the air outside are getting the creosote treatment, too. The pollution is bad, and creosote build-up in the chimney is the main fuel for dangerous chimney fires. If you're seeing creosote on the window, increase the airflow into the stove.

10. Keep your woodstove clean and in good working order. Too much ash in the firebox can block the air intake and make for inefficient burning. Replace broken firebricks and tattered gaskets. Have your chimney professionally cleaned.

Burning wood the right way warms your home, keeps your family safe, makes your neighbors happy, and helps keep the air clean for everyone.