Plywood and open framed/drywalled for air return?


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Old 08-25-11, 12:59 PM
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Plywood and open framed/drywalled for air return?

Our new house uses plywood for the air returns? This normal?
 
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Old 08-25-11, 01:25 PM
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Never seen plywood but some houses just use the wall cavity, no ductwork at all
 
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Old 08-25-11, 04:11 PM
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It probably makes no difference what they made them out of. Air returns often run up the inside of 2x4 walls, where there is drywall on each side. They can also be floor joists, with sheetmetal or waxed cardboard as the panning. If they have to drop below the joists, it's often done with metal ductwork, but it wouldn't "have" to be. They often will end up going into a metal ductwork eventually, since at some point they have to attach to your blower housing.
 
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Old 09-01-11, 12:15 PM
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For example, our basement return air simply uses a wall cavity that is just dry walled in, no special ducting. It then connects to the plywood return which runs all the way to the unit where it then has about 6' of metal ducting that connects it.

How efficient is this? I guess I expected it to be a metal/insulated return.
 
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Old 09-01-11, 12:48 PM
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Panned returns are a pain to air seal when needed. Ideally both supply and return ducts would be 100% sealed from leakage, thus the to and from is exactly where you want it. Using anything other than a sealed cavity, often metal, creates the possibility of pulling in outside air or forcing out conditioned air. Both result in a loss in efficiency and an imbalance in distribution pressures which can add to the loss.

If the leakage is limited to within the conditioned space, the concerns are less, but testing would be necessary to be sure there is no adventurous connection to the outside. Air moves easily between drywall and studs.

Make sure all supply ducts are metal, no substitution there.

Bud
 
 

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