How Much Heat Is Lost Out of an Unused Fireplace Chimney?

Fireplaces

• Fireplaces are an added feature in many homes, helping create a warm, cozy feel even on the coldest nights. Electric or gas fireplaces are typically not a source of heat loss, but wood burning fireplaces are. Even homes with a fireplace insert, such as wood burning stoves, are prone to air leakage and therefore heat loss.

How Much Heat is Lost

• A fireplace is a source of heat loss in 14 percent of American homes, according to the U.S. Department of Energy. When the damper is open, so much heat is lost that you can use up to 30 percent more energy to heat your home. Even if the damper or flue is closed, a fireplace can leak an additional 14 percent or more of air in the home than it otherwise would.

Recommendations

• Verify that the damper is closed when the fireplace is not in use. Hold up a match or a piece of crepe paper inside your fireplace. If it moves, reseal around the damper, using a high temperature sealant or weatherstripping according to the manufacturer's instructions. If you rarely use the fireplace, insert a fireplace stopper into the damper that is taken out before use. You can also install a glass fireplace door to help prevent heat loss. In addition, if there is space between the chimney and your wall, caulk it to reduce air leakage. If you never intend to use your fireplace, you can seal the damper and insert a plug. You can then close it up, using wood or drywall, for example.

Other Sources of Heat Loss

• The number one source of air leakage in American homes is through the floors, ceilings and walls due to inadequate insulation. Only 10 percent of homes leak air through the windows and 11 percent through the doors. Other trouble spots include air ducts, electrical outlets, vents, fans and plumbing holes. Locate as many of these areas as possible and seal or replace them as necessary to improve energy efficiency in the home.