The Fireplace Myth – Why Fires Can Cost You Hundreds

Fire in the fireplaceWith winter upon us, the thought of a warm, crackling fire in the fireplace is probably a quite appealing image to a lot of you. What you probably don’t realize is that your fire will cost you a lot more than the price of a couple of logs.

Your fireplace is one of the most inefficient heat sources you can possibly use. Basically, you’re sending money straight up the smoke stack. While the perception is that you are only sending up heat generated by the fire, the fire must consume oxygen to produce the heat.

Your nice roaring fire can consume and exhaust more than 20,000 cubic feet of air per hour. All that air being exhausted is replaced by cold air coming into the house. The cold air forces your heating system to work hard to warm it up, which is then sucked up by the fire and exhausted through your chimney again. It’s an never ending cycle while the fire is roaring meaning that your heater will be working extra hard and costing you money the whole time.

The most energy efficient decision you can make is to not have fires in your fireplace. If you decide to take this approach, consider plugging and sealing your fireplace flue.

While that is the most efficient approach, it isn’t a whole lot of fun. A winter fire is nice to have once in awhile. If you know there will be occasions when you will want to have a fire, there are still some things you can do to make the fire as energy efficient as possible. You’ll want to keep your fireplace damper closed at all times except when a fire is going. Accidentally leaving the chimney flue open is like leaving a two foot square window open. You also want to make sure that when the damper is closed, it closes snugly and doesn’t leave gaps where air can escape.

Most fireplace dampers are form fitting which prevents air leakage when they are closed. As years pass, however, the damper metal can warp due to the heat from the fires and moisture from the outside. This can cause the seal to loosen which will allow room air to escape up the chimney. Close the damper and light a candle to see if it flickers when placed near the damper seal. If it does, you need to either repair or replace the damper to close the leak.

When you do have a fire going, open the dampers at the bottom of the firebox if your fireplace has them. If not, open the nearest window to the fireplace about an inch and close all the doors to the room. This allows the fire to consume fresh air that hasn’t been heated before exiting up the chimney again. You should also lower your thermostat setting to approximately 50°F while the fire is going to make sure your heating system isn’t heating air that will soon be leaving up the chimney.

Making sure that your damper is always tightly closed when not using the fireplace and following the above steps when the fireplace is in use can save you hundreds of dollars in energy costs each winter that you probably didn’t even know that you were wasting.

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14 Responses to The Fireplace Myth – Why Fires Can Cost You Hundreds

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  2. Dimes says:

    How terribly unromantic! 😉

  3. Amber says:

    What if your fireplace has a blower on it? We have seen a significant decrease in our heating bill by using the fireplace.

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  5. pfadvice says:

    What if your fireplace has a blower on it? We have seen a significant decrease in our heating bill by using the fireplace.

    It will help some as some of the hot air that would be going up the chimney will be headed back in the room. It still takes oxygen, however, to keep the fire burning which is being sucked out of the room. If you are fairly near the fireplace you should feel quite warm, but you’d still be better off keeping the thermostat set at a low temperature so it doesn’t have to work hard heating up air that will be leaving the room soon.

  6. Elizebeth says:

    How much does a fireplace cost nowadays??? That’s the one thing you didn’t say and I need to know.

  7. Garry Byrne says:

    I take issue with the idea fireplaces remove more heat than they provide. You accounted for all the factors except one. The fireplace introduces heat in the form of radiation, both from fire and from heated, insulated brick. When my power was out for three days, my fireplace warmed my house nicely. It also results in my furnace coming on much less often. I will concede that, of all forms of wood burning to acquire heat, the fireplace is the least efficient and that there are some very badly designed ones that just may fit your description. Wood stove is much better. Masonry stove is best.

  8. Pete says:

    I am so tired of this asinine “myth” in itself.

    According to your logic, a fireplace will vent more heat than it can produce which is ridiculous!

    If that were the case, every pioneer on the plains in the ninteenth century would have frozen to death.

    Try Again.

  9. pfadvice says:


    What you fail to take into account is that the people on the plains were not in rooms that had already been heated by a furnace. The reason it wastes heat is that a fire requires oxygen and sucks up the already warmed air in the house with it (which then means cold air from outside needs to be warmed again by the furnace). If you have no heater going in your house you are correct, but most people do.

  10. Robert Stanhope says:

    You are 100% corect a fireplace will suck the heat right out of your house because of the draft that it creats but you can utilize that heat with as you call it a heat exchanger. Fire manegment is the key to making a unit like this work for you.

  11. Bill says:

    I,ve heard this theory before so I did my own experiment. I turned off my heat and kept my 2,000 square foot house warm for over 15 hours with just the fireplace and the central fan on for circulation. The temperature outside was about zero. If I turn off my heat and no fire the temperature drops about 10 degrees in 2 hours. So don’t listen to this stupid article.

  12. skip frantz says:

    TI disagree with some of your thinking. If your fire place has a cover on the front as mine does it eliminates a lot of the room air loss with the vents at the bottom, I turn on the the room fan to distribute the heat that is generated from the fireplace thus heating the room and when the other ceiling fans are used it heats the house somewhat evenly.What I think you need to publish is there are different scenerios for different fireplaces before you go whole hog saying all fire places are bad and you get our wives in a uproar about everything they readype your comment here.

  13. Brian Smith says:

    This article may be true of a ‘fireplace’ but is completely wromg concerning a wood burning stove or a stove insert into a fireplace. All that is required is a combustion air vent to the stove or fireplace to stop the depletion of oxygen in the room. My house is completely heated with a stove with a cost savings of thousands of dollars a year as wood is plentiful

  14. Terry Bartels says:

    After being in the chimney business for 27 years I’ve pretty much seen and heard everything. The fact is that if you are burning your fireplace you may not loose as much of your house heat up the chimney but you will loose about 90% of the heat from your fire up the flue. The major heat loss from your home actually happens when your fireplace is not being burned. This is when the fireplace will pull the heat from your home, make your furnace work harder, and raise your heating bills. With that said, the article as well as those making comments are correct in their own way.

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