Expert: James Ball - 10/29/2008

Question
We have a large doublesided fireplace upstairs and a woodstove downstairs in our timberframed home. I can have a great fire upstairs with no smoke but as soon as we light the woodstove and try to have a fire upstairs at the same time as we have one in the woodstove - upstairs smokes. It is driving us nuts. can you help?

Answer
Hello Nancy, this is a common problem, it is called "Negative Pressure" look at it this way if you have 10 gallons of air going up the fireplace chimney it needs 10 gallons of air from the house and it will usually pull the air from the path of least resistance like the other flue/wood stove or pull it down the fireplace to feed the wood stove. and if you have smoke going up the other flue it will pull the smoke down with the air you need to feed the other. the house needs make up air, maybe the wood stove could get its own air supply? and they should have 2 different heights on top at least 4' taller on the one you use the most.
hope this helped
James Ball