“Pellet stoves are still very popular and are the cleanest and most efficient means of heating with wood. They can either be free standing or inserted into an existing fireplace,” says Scott Haase of the DOE’s National Renewable Energy Laboratory in Golden, Colo.

Pellet stoves became a popular option a few years ago for homeowners wanting to escape total reliance on gas and electric heating systems, but ran into some difficulty when sudden demand outstripped supply causing difficulties in obtaining either the stove or its necessary compressed pellet fuel. Some people complained about being dependent on the manufacturers of pellet fuels, who didn’t have a lot of price competition.

Still, the DOE estimates there are about 500,000 pellet stoves in use in the United States today. Pellet stoves have some downsides: Their fuel costs more than cord wood, it’s not always readily available and the stove requires electricity to operate its continuous feeding system, so a power outage can knock it out of commission.

Wood stoves also can use wood effectively. Newer stoves certified by the Environmental Protection Agency (EPA) can be “extremely efficient, on the order of 70-75 percent, maybe even higher in some cases,’’ says Haase. They produce smoke with particulate emissions vastly reduced from their heavily polluting ancestral cousins, and because they are closed systems like pellet stoves, they generate much more heat than an open fireplace.

Another waycontinental-epa-insert.jpg to go is to have an installer retrofit your fireplace with an EPA-certified fireplace insert. An insert effectively turns your fireplace into a modified wood-burning stove that’s efficient and far less polluting than the standard fireplace.