High efficiency fireplace
Is an open fireplace energy efficient?
I have a wood burning fireplace and wonder if it's a high efficiency fireplace or what I can do to make it efficient. It heats up the living room really well but is it as efficient as it could be?
Answer from Green Energy Efficient Homes
Generally speaking, an open wood fireplace draws more heat out of the house than it contributes, because burning the wood draws oxygen out of your air for combustion and pulls much of the heat from the fire, as well as the warm air inside your house, up the chimney. (Remember, heat rises.) This in turn pulls cold air in through all the air leaks in your house (cracks in walls, doors and windows, attic opening, etc.). So while the heat from the fire may make you feel warmer in the room where the fireplace is located, overall you are cooling the house down.
Not only will the fireplace cool the rest of your house down, it will also cause considerable air pollution, as open fires produce a lot of soot. So the open fireplace you have is definitely not a high efficiency fireplace.
Even if you don't use your fireplace to heat your house, there's a good chance that if you have one, it is a net energy drain on your home energy bill. Fireplaces typically have a flue damper, which should be closed except when a fire is burning. Make sure you have one, and if you do, keep it closed. Otherwise, even when the fire is not burning, the chimney will act as a giant straw, as hot air will rise naturally up the chimney and this will draw cold air in through poorly sealed leaks around windows and doors or in other areas.
In fact, even fireplace chimneys that do have a flue damper often do not
prevent hot air from escaping, because just a few really hot fires burned over
the lifetime of the chimney can cause the metal of the damper to warp, preventing
it from giving a good seal. If you wet your finger and hold it by the fireplace, and
feel a draft pulling air into the chimney flue, or you feel cold air falling out of your fireplace
in winter, your flue damper is probably not providing a good seal. You can solve
this problem with a
You can save a lot of money on heating costs if you use an energy efficient fireplace insert. These wood burning inserts are sealed, so they do not allow large amounts of warm inside air to be sucked up the chimney. They can even be installed so that they draw their air from outside. They throw off a huge amount of heat and they burn much more cleanly than an open fireplace.
If you're renting and looking for a cheap option to heat with wood, you could look into a tin-can stove. We had one in our cottage about 30 years ago; it looks like an oblong oil drum with a round lid on the top near one end, and a round hole at the other end; you put a stovepipe up your chimney, slide the stove into the fireplace, drop the stovepipe onto the small round hole, and then put firewood in the large round lid. This stove kept us toasty warm on one of the coldest Decembers on record - it went down to about -57F! On the other hand, unlike a high efficiency fireplace insert, a tin can stove won't necessarily burn cleanly, so you'll possibly be polluting the outdoor air.
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