Expert: James Ball - 1/11/2011

Question
I have 2n woodburning fireplace in the house, one on the first floor and the other on the second.  Each fireplace has its own chimney that vent to the outside near the roof.  A gas fireplace insert was installed in the first floor fireplace a few years ago (a natural vent fireplace).  I find that the room with the gas fireplace insert is very cold as the cold air from outside flows down the chimney into the room.  I can feel a strong draft.  Is there a way to stop the draft?   Thanks.

Answer
Hello Jim, is this a sealed gas insert? if so then no air should be getting through, if they are gas logs then the damper must stay open.
What is happening is you are getting Negative Pressure in your home (house stack effect) that is hot air rising in your home (and getting out through the attic vents, doors, lights, another fireplace (is it closed?)) your house is a better chimney than your chimney. Also kitchen/bathroom exhaust fans, clothes dryers, Radon systems and the boiler/furnace all take house air out of the house (mechanical negative pressure) your house needs make up air, perhaps an open window in the basement? Or stop the air from getting out the attic and other area’s.
Trail and error until you get this fireplace to work for you, maybe close off the room from the rest of the house to use it (close doors)
Or it could be dirty? 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.
James