Firing Up the Wood Stove

When we moved into our split-level house nearly ten years ago, we thought that the little wood stove on the ground floor would be a welcome advantage come winter. Indeed, we did use it a handful of times that first year, and once or twice after that. But, as warm as it makes the house, we have good reasons not to use it again.

Our old wood stove, it turns out, is a pollution machine. According to the EPA, without pollution controls in our stove, the smoke we would create contains carbon monoxide, nitrogen oxides, volatile organic compounds, and dioxin. It also contains particulate organic matter, which, along with the volatile organic compounds, can be irritating and even carcinogenic.

Sure, our wood stove heats the house, but when it comes to air pollution, our stove might as well be a fireplace.

New wood stoves, however, all have catalytic converters. These devices trap pollutants and burn particulates. The smoke released from the chimney, while not entirely clean, is much easier on the atmosphere and on our lungs. All wood stoves must meet EPA and state emissions standards.

At Grist.org, the advice column, “Ask Umbra,” has been providing wood stove information to readers over the past several years. The author suggests buying dense wood (hardwood is the densest). Buy split logs and allow them to dry six months to one year before burning. The drier the wood, the more efficient the combustion will be. There is even an online resource that lists properties of different fire woods, including the heat given off, ease of log-splitting, and whether or not the burning wood is smelly.

When choosing firewood, sustainability rules apply: Buy local and buy sustainable. The Consumer Guide to Home Energy Savings states that if the wood burned in wood stoves is harvested sustainably then the trees grown to replace the burned logs will absorb more CO2 than the wood burning creates.

The EPA provides a list of things that should not be burned in a wood stove: cardboard and household garbage contain plastics and inks that are toxic when burned; coated, painted, glued, and pressure-treated wood contain toxins; rotted, moldy, and diseased wood can also release toxins and irritants. In order to minimize the risk of bringing allergy-causing mold spores into the house, the EPA also recommends that the amount of wood brought in as spare logs be minimized.

One wood-burning alternative in home heating is a pellet stove. These devices are fed by compressed pellets of wood, crop waste, or paper waste. Electronic controls feed the pellets into a combustion chamber. The combustion is clean and efficient, so much so that the EPA doesn’t bother to regulate pellet stoves. Electricity is required, though, at approximately 100 kilowatt-hours per month.

See a graphic comparison of air pollution from old and new wood stoves, pellet stoves, and oil and gas combustion.

For more information on wood stoves, follow the links below:

The Tao of Stove (grist.org)
Re: Heat (grist.org)
Logging On (grist.org)
Healthier Home, Cleaner Environment (epa.gov)