Expert: James Ball - 10/14/2010

Question
James,

I have a zero clearance fireplace that uses a double wall air cooled chimney.  When the fireplace is not operating I can feel cold air flowing through a "required" chase vent and into the house.  When The fireplace is operating and the flue heats up, this air flow seems to be drawing the warm house air through this vent and outside through the outer wall of the chimney.  My question is:  Is this type of chimney actually causing more heat loss than I am gaining by running the fireplace?    If so, what are my options to limit the heat loss?

Thank You

Answer
Hello Michael, in most cases the Chase is not built correctly, it should be insulated as if it is part of the home, I have had customers that have used Magnetic sheets (like you would use on a work van, from any sign/printers shop).
to completely stop this air flow you might have to rebuild the chase it self.
James