If you have a standard fireplace that vents up a brick and mortar masonry chimney, you probably enjoy building a roaring fire on a cold winter night and cozying up with a glass of fine wine or a good book or somebody special. You may not know that your fireplace is an air polluting energy hog.
A wood burning fireplace vents a lot of smoke and other pollutants out the chimney at the same time that it is sucking cold air into your house from outside to feed the fire. Most fireplaces lose more heat than they gain in this air exchange process, and most fireplaces do not burn wood efficiently enough to prevent dirty exhaust gases from going up your chimney.
You can minimize your personal air pollution at the same time you reduce your fuel costs by installing a wood burning insert inside your fireplace along with the proper stainless steel chimney liner to fit the insert. A fireplace insert is basically a woodstove, except that it is designed to sit inside your fireplace rather than being a freestanding appliance. Inserts are made of heavy sheet steel or cast iron and contain refractory bricks to retain heat as wood burns. The heat is then radiated out into the room.
Modern fireplace inserts are certified by the Environmental Protection Agency (EPA) to burn clean enough to operate even on high pollution days. Inserts accomplish this clean combustion by operating at a higher temperature than an open fireplace, by recirculating combustion gases through a series of baffles and chambers where it is further combusted, and, in some models, by using a catalytic converter to clean up the exhaust.
After an efficient insert is lit and brought up to its optimum temperature, essentially the only compounds going up the chimney liner and into the air are carbon dioxide and water. They burn the fuel much more completely than a regular fireplace and they radiate far more heat back into the house than is lost by drawing cold air in to feed the fire. By installing a stainless steel chimney liner along with the insert, you make cleaning easier and you probably also improve the draft of your chimney system.
A high quality insert, chimney liner, and labor for installation will cost several thousand dollars, but it is an investment that will pay for itself in monetary terms with reduced fuel costs and in aesthetic terms by providing you with a more comfortable heated space and knowledge that your exhaust is clean enough even to satisfy the EPA!