This top chimney damper is called a Lock Top damper and actually doubles as a chimney cap.
This top chimney damper is called a Lock Top damper and actually doubles as a chimney cap.

Installing a chimney damper does not require any special tools. If your fireplace does not already have a damper installed, especially if your home is older, it is prudent to install one. The energy savings that the damper will bring about will cause it to pay for itself over time. A damper generally sits right before the smoke chamber in your chimney. The damper is to be opened when a fire is lit in the fireplace and closed when it is not in use. This will prevent the air that you have heated from rising out of the home and also prevent cold air from outside from entering. Both wood burning and gas fireplaces should have dampers to prevent energy loss, even if the chimney is not in use.

Chimney flue sizes are generally about standard. For square flues, take measurements of your flue system and decide what size damper you will need. A single flue chimney is very easy for damper installation. The damper will fit right up into the flue system and should sit above the smoke chamber. Getting the damper to stay in place in a flue system such as this is as easy as tightening the screws that come with the damper into the walls of the flue system. You should always wear protective gloves when handling sheet metal because there is a tendency for sharp edges. You will need a screwdriver to tighten the screws into place.

For round tile chimney flues installation is even easier. After locating the appropriately sized damper, all you will need to do is push the damper down into the flue system. The damper should fit tightly. Seal the edges with a silicon to ensure it does not move over time. For a metal chimney installation is much the same only no silicon is used. To be sure that a damper that you have installed yourself is properly installed it is a good idea to consult a professional. Usually they will charge you a service fee for coming out to your home but this fee is small compared to the peace of mind you get from knowing you have a properly installed fireplace damper maximizing energy savings.

Top chimney dampers are another option. These seal at the top of the chimney and prevent animals and pests from getting into the chimney while still keeping your heated air inside the home. This is different than the chimney throat dampers described earlier in this article; chimney throat dampers sit inside the flue system above the smoke chamber.

Clay Lamb
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6 thoughts on “How to Install a Chimney Damper

  1. Greg, I cannot think of a good reason why you would need a damper.
    But I would be sure and put a chimney cap on to it ,to keep rain out.
    I hope that you really enjoy your outdoor fireplace ., because my wife and I sure do!

  2. Out fireplace was built in the 30s, and was not built with a damper. It’s square and brick, but my dad is convinced that it’s very expensive and unreasonable to try and add a damper. He doesn’t like the top damper because he doesn’t believe they will help the chimney draw properly. We’re not in your area, but I was wondering if you could shed a little light on the feasibility of adding a damper and whether a throat or top damper would be more effective for us. Thanks.

  3. Im a proponent for top sealing dampers as they allows the chimney to preheat the stem from room air allowing the air travel up the chimney much better. In most cases they have a much better sealing of the damper preventing air movement up and down of the chimney when closed. I’ve installed cast metal dampers a number of times because a customer wanted this. I would go to the and find a chimney sweep who can fit a properly sized damper for you, more so than a masons as in most cases they do not have to deal with most air balance or pressure problems in the home. I’ve supplied a link to the damper I feel has worked best for me. This is probably the most common size but your flue must be measured first:

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