Top-Performing Pellet Stoves

Wood pellets are made by extruding sawdust and wood shavings through quarter-inch (6 mm) holes in a large die under very high pressure; natural lignin in the wood binds each pellet. Most wood pellets are produced as byproducts from lumber mills, but, even if produced directly from trees, the fuel should be close to carbon-neutral when examined on a life-cycle basis as long as new trees replace those that are harvested and the raw material or pellets aren’t transported too far. The resultant pellets are very dry (typically about 5% moisture content) and very dense, with a heat content of 8,000–8,500 Btu/pound (19–20 MJ/kg) or 16–17 million Btu/ton, according to Don Kaiser, executive director of the Pellet Fuels Institute.

In a pellet-burning stove, boiler, or furnace, an auger feeds the pellets into the burnpot, and a blower supplies combustion air, ensuring fairly efficient and clean combustion. Pellet-combustion appliances are exempt from U.S. Environmental Protection Agency (EPA) limits on particulate emissions (required of woodstoves), but their emissions are generally below 2.0 grams per hour, according to experts