Expert: James Ball - 11/13/2008

Question
When I have a fire in my fireplace I get smoke coming in from the furnace. My mother had a chimney sweep come in a few years ago and he took out the old damper and he installed a top sealing damper cap. What I think is happening is the smoke is rolling under the cap and being sucked in by the furnace. What can I do to fix this. I really like to have nice big fires in my fireplace and its a big bummer to have smoke rolling up stairs from the furnace. Thank you!!!  Jeff

Answer
Hello Jeff, what is happening is you are getting Negative Pressure in your home, if 10 gallons of air is going up the chimney per minute then it needs 10 gallons of air per minute and it will pull the air from the path of least resistance from your home and in most cases it will pull that air down an other flue and with it smoke/odor the house needs make up air. maybe open a window in the boiler/furnace room? 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 Ball