Wood Stove Efficiency and Emissions: 1984

Image Gallery

Article Tools

Image Gallery

Print

E-mail

Comments

RSS

Have you put off buying a better-performing wood-burning heater? Perhaps the time has come.

One of the quickest and most convincing ways to learn the true worth of a gallon of oil is to cut enough firewood to duplicate its heating value. In raw Btu, it takes about 20 pounds of wood to equal a gallon (about 7.5 pounds) of fuel oil. Imagine toting a winter's worth of fuel oil home in quart bottles—after having pumped it up out of the ground—and pouring it into a heater every few hours! As appalling as that prospect sounds, people who burn wood perform a ritual that's very similar ...except that they haul twice as many pounds every winter.

Contemplating the amount of labor that goes into heating with wood can be depressing, but what really hurts is the fact that about half of the energy available in the fuel goes to waste. Worse yet, much of the 50% that gets away pollutes the air or sticks to the inside of the chimney.

The trade-offs of heating with wood have been a fact of life for decades. And, until the question of pollution came up a few years back, few wood burners considered it a bad deal. With a moderate amount of honest labor, anyone who burns wood can save on his or her heating bill. And trees are a renewable source of energy. The alternatives—oil, gas, and electricity—are more expensive than wood and are becoming even pricier as the supply of fossil fuels is depleted. Furthermore, fossil and nuclear energy sources can't lay claim to great efficiency themselves. By the time usable heat is delivered by most conventional energy sources, at least half of the Btu have escaped. And, just as is the case with wood burning, pollution is one of the major by-products of inefficiency. Therefore, we wood users must ask ourselves two questions about this tradeoff: Just how bad is the problem of pollution from wood stoves, and what can be done about it?

SMOKE GETS IN YOUR EYES

In some locales, wood stove pollution is quite serious, constituting the major source of particulate emissions. And on a national basis, wood burning produces a significant share of some very dangerous compounds. According to Dr. Dennis Jaasma, a wood-combustion research scientist at Virginia Polytechnic Institute and State University, the most threatening pollutants are particulates, vapor-phase hydrocarbons, and carbon monoxide. All of these substances can be drawn deep into the lungs through normal breathing, and thus pose various health hazards. Scientists don't know for sure what the annual national contribution of wood burning may be to the emission of these compounds, but estimates have been made that the numbers are about 0.7%, 2.5%, and 4%, respectively. (By comparison, diesel engines contribute about 1% of the national annual particulate emissions and are regulated by the Environmental Protection Agency.)

RSS | Comments | E-mail | Print