We have a 1985 double-wide which has (as I believe they all do) a down-draft furnace. Would this be why when the furnace turns on, there is a cool draft that comes through the door (louvered) where the furnace is housed? Could I block that off (on the inside of the louved door) with some cardboard to stop the draft, or could I put weather stripping around the door to seal it better. It is a little loose on one side. Thanking in advance.