How to Make Your Fireplace More Efficient

You can make your fireplace more energy efficient with a few do-it-yourself projects.

| Feb. 12, 2008


An open masonry fireplace seems cozy, but it's not efficient for home heating.


As you sit by the fireplace enjoying the glow on these cold winter nights, are you content knowing you’re using a renewable fuel to warm your home? Depending on the type of fireplace you have, it may actually waste more energy than it creates throughout the season. The problem is that most heat goes up the chimney, drawing cold air into the house to replace the heated air. When a fire isn’t burning, warm air can still escape through the chimney. Many products are promoted as increasing the efficiency of your fireplace, but not all of them are as effective — or safe — as you might like them to be.

  1. fireback is simply a heavy sheet of metal (traditionally cast iron) behind the fire. In addition to protecting masonry in the back of the fireplace, a fireback theoretically reflects heat into the room (instead of all the heat going up the chimney). But don’t expect significant results if you add a fireback to your fireplace. Wood-heat expert, John Gulland , says, “Firebacks had a little validity 100 years ago when there weren't many good alternatives, but these days they are mostly decorative.” Estimated cost: $75 to $350.
  2. The  damper is the metal plate that regulates airflow through the chimney. Some dampers fit snuggly when they’re new, but frequently warp within a year or two, producing a loose fit and allowing air to leak past them. Chimney cap dampers close the entire top of the chimney, so they reduce heat loss when the fireplace is not being used, but don’t improve efficiency otherwise. Estimated cost: $160 to $400 for a chimney cap model.
  3. Fireplace doors are supposed to reduce the amount of air that would otherwise be siphoned up the chimney. Depending on the type of glass in the doors, some heat still radiates through the doors into the house. “Cheap doors use tempered glass, which breaks if you close the doors when a fire is burning. Ceramic glass doors can produce a small efficiency improvement but are stunningly expensive. Fireplace doors are almost never tight enough to prevent cold air from backdrafts when the fireplace is not being used,” Gulland says. Estimated cost: $200 to over $1,000.
  4. Grate heaters and radiators aren’t as large as complete fireplace inserts (see below), but capture a significant amount of heat from the fire and force it into the house. “I consider these to be a hazardous product because they actually make heat,” Gulland says, “But a decorative masonry fireplace isn’t designed for heating, and the building code clearances were established before this kind of thing was contemplated. So, they don’t prevent overheating of adjacent combustibles. I don't recommend these at all.” Estimated cost: $410 to $615.

To make your fireplace truly efficient, you’ll want to install an insert approved by the U.S. Environmental Protection Agency (EPA). A fireplace insert is basically a woodstove that fits into a masonry fireplace. Within the last 15 years, fireplace inserts have become much more energy efficient. “To improve efficiency and reduce standby losses, this is the only option I recommend. To be safe and effective, the insert must have a stainless steel liner run right to the top of the chimney,” Gulland says. Estimated cost: $3,000 and up.

If you’re not using your fireplace regularly, inflatable plugs can stop warm air from going up the chimney when the fireplace is not in use. Estimated cost: $50 to $70.

For more information on fireplaces, read Choose a Fireplace for Beauty and Warmth.

Do you have other suggestions for making fireplaces more efficient? Share them in the comments section.

8/8/2014 2:53:00 AM

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1/27/2014 5:01:25 AM

Though I agree with most of the article, I think the statement about the functioning of the fireback is somewhat too simple. Firebacks were used for centuries as the heating system because they radiate heat instead of heating the air. see also the Radiator & Efficiency paragraph in the following page: Comparing them with air heating systems isn't completely fair in my opinion.

12/26/2013 7:30:49 PM

Just purchased new cast iron fireback. Then for fireplace sides I realized I could use cast iron griddles (large) on either side to protect masonry. If it provides any heat great--but the cast iron does protect masonry.

12/25/2013 8:09:53 AM

The article states-" “Cheap doors use tempered glass, which breaks if you close the doors when a fire is burning." I have been using tempered glass in the fireplace door for 28 years, it has not broken yet.

kevin chilcutt
11/13/2013 11:45:22 AM

We have an 1800 SF mobile home. It turns out they actually put a pretty good fireplace in these, probably due to wanting to make sure there are no fires. We now heat almost exclusively by this. It has glass doors and a recirculating fan around the box. This works well if you close the doors, but I find it does not otherwise. Open doors seem to get the ehat further out in the house. One thing we do is use both seasoned wood and green but not wet wood. Once the fire is going with seasoned wood and there is a bed of hot coals, the greener wood is added. This burns hot, has less ash and smoke. The trick is to make sure you have a hot bed first. Not unlike my tractor that will run on kerosene, but you have to have the engine hot from gasoline first. We also burn some pine, but make sure we burn out the soot on a regular basis. We make sure the grate is good so air can get to the coals. This might mean buying a new grate each year or two. Small price for the amount we use the fireplace. I would like to get an insert or a second stove type and run the pipe out a window. Wife not big on the idea yet.

john hollar
2/3/2013 12:24:53 AM

The fireplace in question is an existing masonry fireplace that is 40 plus years old and of quality construction with a chimney at least 20 ft with additional 4-5 ft over the roof line!!Thanks John H

7/12/2008 11:57:09 PM

I found an old cast iron stove that could not be used anymore. I took the sides to use as a fireback in my stone fireplace. The sides have animals cast on them and add beauty as well as warmth to my 1915 one room school house. Another way to reuse rather than buy new.

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