Expert: James Ball - 12/20/2009

Question
I live in a split level home with a fireplace in the living room and another down stairs in the family room.  They share the same chimney. the problem is when ever I try and burn in the down stairs fireplace, with damper open,  we get smoked out.  I had the the chimney cleaned about 8 mo. ago and the sweep said it looked good...Could it be a design problem ?

Answer
Hello Jane, what you have is a Negative Pressure issue, look at it this way if 10 gallons of air goes up a chimney per minute then in needs 10 gallons of air to feed it and that air is coming from the house, the house is getting this air from the other fireplace and with  the air it is pulling the smoke down or visa versa. 2 top mount damper caps might help and learning to use these fireplaces too.
Try closing the damper of one fireplace, then opening the other damper and a window fully in that room and try to light a piece of incense and see if the smoke goes up, if so then light your fire. repeat for other fireplace.