Expert: James Ball - 11/24/2009

Question
Our home has two fireplaces, one above the other, both wood burning.  Both flues are the same height.  If we use one alone we always have a downdraft, which forces us to put a fire in both, or just not use either.  How can we fix this without it costing a fortune.  Thanks so much.

Answer
Hello Lucy, this a common problem and it is rare to be able to get both to work, what is  happening when you use one that fireplace needs make up air to work (10 gallons of air per minute going up the chimney it needs 10 gallons of air to feed it.
so what is happening is the smoke and air is going up the first fireplace and the other is pulling down make up air (along with smoke).
Is the other damper closed? if you put a top mount damper cap on leash fireplace then you can close off the one you are not using and should have no smoke at all coming back down (maybe open a window in the basement to give the fireplace and house make up air)
I would have a local Certified Chimney Sweep (www.csia.org, there you can look up by zip code to find one near you) take a first hand look at what you have they should be able to help.
Hope this helps
James