Q&A airtight wood stove - Excessive condensation

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New Member
Staff member
Nov 27, 2012

We have an airtight woodstove vented to an outside cinderblock & terracota lined chimney. There is an air damper on the front of the stove (it vents from the back) & we have a stove pipe damper installed. We have experience excessive condensation running down the chimney & back inside the house through the chimney ash cleanout. The cleanout is located inside the house approximately 18 inches below the terracota thimble the vent pipe feeds out. The stove, cleanout & vent thimble is located in the basement. The basement is a walkout basement in the back and subterranean in front. The stove, vent & cleanout is located approximately 2 feet below ground level. We have spoken with several people & received conflicting stories. A professional chimney sweep said possible chimney flue cracks. A stove dealer said UL states no pipe damper, only use the one on the front of the stove. Where can I find specific info on the web about proper installation specifications for an airtight woodstove? I need this info ASAP & do not want to wait for mail time. Thanks for any help.


The problem probably relates to the age of the stove and the way it is being used. Older airtights were creosote hogs...they had little or no mechanism for burning clean. In addition, the stovepipe damper is allowing you to choke off the fire excessively - causing your stove and chimney to turn into a distillery.

1. Get a newer, high efficiency stove
2. Burn the stove with less wood and more air - keep a good flame on the fire (do not smolder it)
3. Make certain your wood is dry and seasoned
4. Stop the use of the stovepipe damper.
5. Line the chimney with a smaller diameter stainless pipe (to match stove.)
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