Chimney Dampers - Wood Burning and Gas Fireplaces
Features of Chimney Dampers
A chimney damper is normally found at the base of the chimney where it opens up into the firebox. These are necessary to keep heated air from escaping out of the home via the chimney and should be shut when the fireplace is not in use. They also keep outside elements, such as the rain and cold air, from entering the chimney and the home. Chimney dampers are used in both wood burning and gas fireplaces.
Heated air tends to rise and in a fireplace this means rising up through the chimney. This rising air causes suction, known as the 'chimney effect', which actually sucks more warm air from inside the room up the chimney. More than half of the heated air can be lost in this way. Using a chimney damper can greatly increase the efficiency of your fireplace as heated air is kept inside the room when the fireplace is not in use.
Many older fireplaces may not have a damper installed so this would need to be done even if the fireplace is no longer use. This is mainly to keep cold air from coming into the home. Installing a chimney damper is relatively easy and doesn't require any specialist tools. It may still be a good idea, however, to have some professional help to ensure that the damper is installed properly.
Most chimney dampers are positioned in close proximity to the flames of the fire and are also exposed to rainy and cold conditions from outside. Dampers are normally made to withstand extreme temperatures but after some years of use they can become warped and damaged which means the damper will not be sealing the chimney properly, leaving gaps. Heat will escape through even the smallest gaps in the damper seal and this accumulated heat loss means the main heating system will need to work harder to keep the room warm. This will inevitably cost extra and this extra cost can add up to a surprising amount. Chimney dampers can also develop a thick layer of creosote and mortar which means they will need to be replaced.
To have a damper replaced, simply remove it from the chimney and take it to a fireplace dealer, sheet metal shop or metal fabricating plant to have it duplicated. The other option is to call a professional to remove and replace it. The cost of having a new damper installed will be worth the savings to be made on heating bills. An alternative to the chimney damper would be to install fireplace glass doors.
The damper should always be fully open when starting a fire but through trial and error experimentation the minimum opening can be found for various fire conditions. When altering the damper opening always give the fire time to adjust before making any more changes. If smoke or odors start coming into the house then the damper is not open enough. It is usually easier to just leave it completely open when using the fireplace. Chimney dampers can also be attached to the top of the chimney thereby providing a chimney cap and damper in one accessory.