Daughter's house has two A/C systems. One has a return air plenum, the other does not. The one w/ the return air plenum serves the master bedroom. Unfortunately, the plenum merely collects air from a single point & moves it via a torturous route to the underside of the A/C unit, (I know, stupid, but that's the way it works.) meaning that all the return air has to slither under the door to get out of the BR when the door is closed.
We want to install return ducts in the BR - it's rather large & does not get or stay comfortable, year round- believing it will solve the gomfort problem. Currently it is serviced by two inlet ducts feeding about 400CFM of conditioned air. To properly return that much air, seems to me you'd need about the same number of square inches of space under the door therefore the door has to be cut off about 3 inches from the floor.
Does such a move make sense? There is plenty of space on the surface of the return air plenum to splice the new return air ducting into.
When we had our house built, the HVAC contractor chose to place the inlet air openings along the outer walls & the return openings at the inner walls of every room. Makes sense to me. Said the outer walls were the source of hot air in summer & cold in winter.
I'd like to put in two like sized (compared to the inlet ducts) return air ducts in the room. Does this sound rational?
The Glass Masterworks
"If it scratches, I etch it!"