How to Fix a Smoky Fireplace

Smoky Fireplace? How to fix a smoky fireplace

Is your fireplace letting smoke into your room? A smoky fireplace is a nuisance and a downright danger because fireplace smoke carries odorless but deadly carbon monoxide. Diagnosing the cause of your smoky fireplace, or back puffing, is essential to finding the most efficient and cost effective solution to fix a smoky fireplace.

What to do if your fireplace smokes

First, if your fireplace smokes only when you first light your fire, the solution is simple and free! You merely need to warm up your chimney’s flue before you light the fire. Tightly roll a piece of newspaper, light one end like a torch, and hold it inside your fireplace as high as you can. Then immediately light your fire. The pre-warmed flue will ensure the smoke goes up the flue instead of into the room.

If the fireplace allows smoke to escape into your room only on windy days, the answer is to install a Vacu-Stack Chimney Cap. As the wind passes through the Vacu-Stack Chimney Cap, it creates a vacuum above the flue. The harder the wind blows, the harder the Vacu-Stack pulls the smoke up your chimney, keeping your room smoke-free.

Vacu-Stack chimney cap
Vacu-Stack Chimney Caps for round masonry flues
Vacu-Stack Chimney Caps for air-cooled flues
Vacu-Stack Chimney Cap Adapter for square or rectangular flues

If the smoky fireplace problem happens on calm days also, go through the following steps to find a solution:

First, check if the fireplace is getting enough draft to allow air to move up the chimney. Shut off any exhaust fans that may be running, even upstairs in your home. Those exhaust fans are pulling household air (and maybe your fireplace’s smoke) to the fans. If shutting off exhaust fans doesn’t stop the back puffing, test by opening a door or window near the fireplace to see if that corrects the problem. If your fireplace no longer smokes when a door or window is opened, installing an Air Supply Ventilator is the least expensive option. A pricier but sure-to-work option is installing an Enervex or Exhausto Fan Chimney Cap.

Fireplace to flue ratio

The area of your fireplace opening should be no more than 10 times the area of your flue opening. To find the area of your fireplace opening, multiply its height by its width. To compute the area of your flue opening, multiply its inside length by its inside width. If you have a round flue, the formula for area is 3.14 times the radius times the radius.

For example, let’s say your fireplace opening is 30 inches wide and 20 inches high and you have a square flue with an inside width of 8 inches. The area of the fireplace opening is 600 square inches and the area of the flue opening is 64 square inches, making your fireplace area roughly 10 times your flue area. The flue and fireplace opening are properly sized.

If your fireplace opening is more than 10 times the size of your flue opening, installing a Smoke Guard can improve the proportions, allowing the flue to work more efficiently and eliminate your smoky fireplace problem. The Smoke Guards come in either brass or black.

 smoke guard to fix smoky fireplace

If a Smoke Guard will not sufficiently correct the proportions and all of the above options did not work, your only solution is an Exhausto Fan Chimney Cap.

Enervex Fans: guaranteed to fix a smoky fireplace

An Enervex Fan will cure any and all back puffing, smoky fireplace problems. An Enervex or Exhausto Chimney Fan is a weatherproof exhaust fan that mounts on the top of your chimney. These powerful fans create a forced air draft that sucks the smoke from the flue, ending forever the problem of a smoky fireplace. Enervex Fans can even end tricky draft problems found with see-through fireplaces and poorly proportioned corner fireplaces. Also, count on these chimney exhaust fans to put an end to problem odors from your chimney.


Tom has been writing for the blog since 2011 and has loved sitting in front of the fireplace since he was an itty-bitty boy.

Posted in Fireplace and Chimney Maintenance, Safety Tagged with:
4 comments on “How to Fix a Smoky Fireplace
  1. mordecai schwartz says:

    i want to get more information on weatherproof exhaust fans

  2. Eriko says:

    what do i do if the smoke goes into the basement as well as going up through the flue? is there a way to seal the fireplace so smoke can not go into the basement?

  3. Fritz Alexander says:

    My fireplace has two 45degree turns on top of my stove before it goes up the chimney . The turns are about 20 inches apart and they were made by the stove people that installed my fireplace. The pipes are
    maybe 6 inches across and 2 inches high and straight across before it turns up the chimney. The house always smell of smoke and the sweeper I hired this year said the pipes should be angled and not 45 turs.

    The furnace people say they did it correct.

    I’m 77 years old and have always had a fireplace, but never one that smokes like this- -I need suggestions ASAP. Thanks very much.

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