A crackling fire in the fireplace feels warm and cozy, but traditional wood-burning is a major energy waste. According to the U.S. Department of Energy, a blazing hearth sends as much as 24,000 cubic feet of air per hour up the chimney, along with about 90 percent of the heat produced by the fire and some of the heat produced by the home’s furnace.

Fireplaces also generate a lot of air pollution. Wood smoke contains carbon monoxide, nitrogen oxides and fine particulates that can aggravate asthma, allergies and other health conditions.

Several options are available for upgrading the family fireplace, both energy- and pollution-wise, without sacrificing coziness:

* Wood stoves. Units certified by the U.S. Environmental Protection Agency (EPA) generate only two to five grams of particulate matter per hour of operation, compared with 40 to 60 grams per hour from a conventional fireplace. Current units operate at 80 percent efficiency—similar to other home heating sources. They come as either a freestanding model or a unit that inserts into an existing fireplace; many come with blowers to direct heated air into the living space.

* Pellet stoves. Instead of wood logs, these stoves burn small pellets made from compressed wood and other plant waste, and produce so little pollution that they do not require EPA certification. Pellet stoves do require electricity to feed pellets into the combustion chamber (about 100 kilowatt-hours per month under normal usage), so they will not work during a power outage, unless powered by a separate generator. Like wood stoves, pellet stoves are available as freestanding units or fireplace inserts.

* Gas fireplace inserts. Natural gas or propane-fueled inserts offer the warmth and ambiance of a fire without the need to load wood or pellets or dispose of ash. Gas inserts are up to 80 percent efficient and generate low levels of pollution.

Other options also exist for enhancing the operation of an existing fireplace and preventing excessive heat loss:

* Tempered glass doors. Installation of airtight hearth doors enables the family to keep both the doors and flue shut when the fireplace is not in use.

* Heat-air exchange system. This improvement blows warm air back into the room, minus the smoke. 

* Caulking air leaks. Provides a low-cost barrier to keep air from escaping from around the fireplace doors, flue and chimney. 

* Lowering the thermostat. A good rule of thumb is to keep the house between 50 and 55 degrees when the fireplace is in use, and shut doors leading into the room.

* Cracking open a window near the fireplace. Creates a healthier experience by increasing fresh air flow and minimizing smoke inhalation.

Source: Adapted from Union of Concerned Scientists (ucsusa.org).

More Cool Tips for Hearthside Heat

Stay cozy—and green—by following these suggestions for wintertime warmth.

* Stay informed: The Environmental Protection Agency (EPA) is a comprehensive source of information and advice on the cleaner-burning wood stoves and fireplaces (epa.gov/woodstoves) and their efficient and safe operation (epa.gov/woodstoves/efficiently.html).

* Shop eco-friendly firelogs: A recent EPA study comparing emissions from real logs and brand-name artificial logs found that the firelogs emitted about 75 percent less carbon monoxide, 80 percent fewer particulates and lower chemical emissions than real wood. They also proved more efficient, with a heat content of 12,620 to 15,190 BTUs per pound, compared to oak, which burns at around 8,300 BTUs per pound.

Several companies manufacture firelogs made of recycled biomass products like wood sawdust, ground nutshells and coffee grounds. All are low-emission alternatives to cordwood. Some logs even produce a natural crackling sound, without throwing sparks.

Two to investigate: Pine Mountain Brands Java-Log firelogs divert 12 million pounds of coffee grounds from landfills each year and feature recycled packaging (PineMountainBrands.com); Duraflame’s firelogs have a 30-year track record creating heat from renewable resources (Duraflame.com).

* Follow instructions: For wood stoves and fireplace inserts, use only firelogs made from 100 percent compressed sawdust (no wax). Wax and biomass logs are intended only for open hearth fireplaces. Never add an artificial log to a natural wood fire that is already burning, as it could flare up. Don’t poke burning artificial logs because they could flare up; this also keeps any flaming wax from clinging to the poker and then dripping onto the floor.

Source: Adapted from EPA.gov.