I have a 90-year old house in Seattle. Exterior walls are constructed as follows: lath and plaster, uninsulated 2x4 stud bays, plank sheathing, cedar clapboard, 1" foil-faced styrofoam, vinyl siding. ...
My house has an 80% efficiency gas furnace in an interior mechanical closet with the return air path below the furnace and through a grille under the closet. However, since the furnace is not a sealed ...
So my interior furnace closet has a huge duct in it that connects the closet to the unconditioned vented attic right above it. Needless to say, this is a huge air leak into the conditioned part of the ...