My wood burner fireplace insert is leaking cold air into the house (and sucking out the heated air I'm sure). I know the damper is closing completely and I think the outside air is coming down between the walls of the double-wall pipe. I've tried to find insulation to put in the void to stop the flow but haven't had any luck. Does anyone know if there is a specially designed insulation for use in such hot environments? Will regular insulation withstand the heat (minus the paper)? Your help would be appreciated.
James