Don't Let Fireplaces Put a Chill in Your Home. A traditional open fireplace can be one of the most expensive energy problems in many homes. This is because your fireplace's chimney is, in effect, a large hole in your house. This creates drafts elsewhere in your home as cold air is pulled in to replace the air that is sucked up your chimney. A fireplace is also a very inefficient heating device. The hotter the fire gets the more house air goes up the chimney.
If your fireplace has a chimney damper, make sure it is closed when you're not burning a fire. This will slow the flow of warm house air up your chimney. Be sure to open the damper before starting your next fire – perhaps you could hang a small tag from the damper to serve as a reminder.
Many fireplaces also have doors. These doors reduce the amount of indoor air going up the chimney, but don't eliminate air leakage. Keep these closed when no fire is burning to slow the loss of room air.
Fireplace inserts are a popular way to improve the efficiency of open fireplaces. A fireplace insert is like a wood stove that is designed to fit into your fireplace. The best inserts have fans that circulate room air through spaces within the insert and distribute it around the room.
Many older fireplaces are never used. The best way to reduce heat waste from these is to seal them off altogether. Seal the chimney above the roof to keep outdoor water and air out of your home. This outdoor seal should cover the top of the chimney and be made of waterproof galvanized steel or aluminum. Inflatable pillows are also available that seal the area where the fireplace connects with its chimney.