We have separated the return air ducts from the supply air ducts by taping off the furnace filter. We can now test them separately for leakage. Once again, testing only the return duct, the duct blaster, showed a leak so large that a measurement figure was not given. We left the duct blaster fan running and we headed out with a fine-tooth comb to inspect the return air duct system.
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It was not long before Jay, who had returned to the attic, had set off leftover fireworks for himself. He knew how much that clam chowder I was looking forward to. The return air duct went from the ceiling register to a metal box that sat over an open chase that went from the attic downward, behind the bathtub wall, to the basement, where it connected back up with the furnace. Most of the air from the duct blaster from that open vertical wall space was coming back up into the attic. The heating contactor used the framing space behind the wall of the bathtub as a return air duct when the house was constructed. He did this without sealing the top of the cavity of the wall or the access holes for plumbing. The homeowners have, therefore, heated the attic for years and provided a warm place for a cat or two to build an ever-expanding trail system. Bring the Clams on here. We will see the reward of a lower electric bill and a more effective, comfortable home when we have a contractor seal the top of the chase around the metal return air box and stop the air from escaping to the attic. The sealing of home heating ducts is considered to be one of the most cost-effective measures for a lower energy bill. I would recommend the addition of an effective heat pump for this home with the heating ducts performing as they should. The addition of a heat pump and then just blowing your savings into the attic is of no use.