Q: Jason, I’m trying to measure my fireplace for a Chimney Balloon, but what part of the flue do I measure? When I open the glass doors on the front of the hearth I look up and see the damper. When that damper is open (it opens downward) I see more of an open amount (Seems like the width of the fireplace) and then it slowly decreases in size to the main tunnel way up to the damper on the top of the chimney. This picture is taken just above the fireplace damper.
This main tunnel is approx 6 -9 inches by 12-15 inches. Did I measure correctly?
A: The expanded location (smoke chamber) just above the damper is the more convenient location for your Chimney Balloon to be installed, but that will probubly require a larger Chimney Balloon. You are looking for an area in your Chimney that is close enough to touch with your hand and has roughly parallel walls. Since the tapering starts after the damper opening the spot right above the damper is a perfect spot for the Chimney Balloon. Both gravety and the firepalce flues taper will hold the balloon down close to the damper and help it seal well. Here is a link to the Chimney Balloon sizing page that will help you see the best way to measure your flue. http://www.chimneyballoon.us/Chimneyballoonsizing.html
If odor is the main issue I usually suggest that the Chimney Balloon be installed as low in the chimney as possible to seal off more of the odorous chimney surfaces. – Jason