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Community and Q&A

Improving panned return ducts

runner9 | Posted in Energy Efficiency and Durability on

Our bungalow is a standard setup, with a 2 story addition added later. In the whole house, best I can tell, there are 3 return ducts, all on outside walls of the original house (1 is now interior), all on the 1st floor and all panned. I can access some of them from the basement.

The 2 farthest from the furnace are panned across to the center of the house, then in a duct going below the joists, then back into a panned duct that goes above the duct pushing air out, and then into another duct that goes back to the furnace, if that makes sense.

Is it better/more efficient/cost efficient to:

1. remove the drywall type product used to box in the floor joists where I can reach it, seal the inside of the other three sides as best I can, then attached new drywall or sheet metal to form a new bottom and also seal that, or

2. tear out the sections I can reach and install new metal ducts?

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  1. GBA Editor
    Martin Holladay | | #1

    Panned ducts are never a good idea, and are a code violation in most jurisdictions.

    You need to install new return-air ducts. Make sure that they are adequately sized; many return-air systems are undersized. Galvanized ducts are preferable to flex ducts.

    If the return-air system uses stud bays as ducts, you need to re-route the ducts. If these empty stud bays are on exterior walls, you need to fill the empty stud bays with insulation.

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