You can increase the energy efficiency of your wood stove by installing a damper. This will mitigate the "chimney" effect, which is responsible for stealing the warm air generated by a wood stove up the chimney once it is turned off.
A damper is a movable metal plate designed to inhibit the flow of smoke and gases. Its purpose is to increase the efficiency of the wood stove by keeping the house warm when the stove is not in use. This means that the damper must be fully closed when the wood stove is off, and just as importantly, fully open when the wood stove is in use. If it is not fully open, the stove will smoke.
Before purchasing a damper to install, it is necessary to determine which kind of damper you need for your stove. There are basically two kinds of dampers, the bypass damper and the pipe damper. The bypass damper is located inside the stove, near the flue collar.
The flue collar is the term used for the connective opening between the stove and its pipe. While the bypass damper is more of a plate, the pipe damper is more like a valve. It is actually inside the stove pipe and can be moved manually by means of a lever outside of the pipe. The following instructions will mostly concern the pipe damper.
Step 1 - Purchase the Damper
It is key to make sure that you are purchasing a damper that is designed for your woodstove. This may mean contacting the manufacturer directly for professional advice as to what kind of damper you need. You may be able to buy the damper directly from the manufacturer.
Step 2 - Measure
With your tape measure, measure up the stovepipe according to how far the instructions specify (about 4 to 5 inches). Mark with the marker. Make a hole with the drill.
Step 3 - Push Pin
Fit the damper's pin through the damper plate to make sure it is a good fit. Next, place the damper inside the stove pipe and then from the outside of the pipe, stick the pin through the hole you just made and through the damper plate. Press hard to make a mark in the pipe wall that you can see from the outside.
Step 4 - Drill Another Hole
Drill another hole exactly into the mark you just made.
Step 5 - Complete
Finally, you can fit your pin through the outside of the stove pipe hole and then through the damper plate that you are holding on the inside of the stove pipe. This time run the pin all the way through the other hole. Lock the damper in place according to instructions.
Now you can manually open and close the damper to maintain your stove as efficiently as possible.