HVAC return connects to attic... seal it off?
While unrelatedly digging through my (unfinished) attic, I realized that the HVAC return is open to all of that hot air. Basically the wall with the return register is actually open to the attic at the top.
I don't know enough about these systems to say if it's definitively a problem, but it seems suspicious as I think I'd be using the AC to cool off a bunch of hot attic air. It's a single-story home in the bay area and the HVAC system was replaced under two years ago.
Should I seal it off? If so, is something like OSB/plywood sufficient, or are there other considerations? The attic has insulation, but it's probably so old that it should be replaced with something more up to modern spec... that'll come later.
Rough diagram: https://imgur.com/kKvqiis - the blue box at the top is what I'd add to close it off.
Posted Apr 7, 2022, 11:56 PM UTC
Not only cost more to cool the attic air. But will be dirty air.
You need to have the proper ductwork installed. Also you should save enough the first year of the cooling bill to pay for this.
The ducting to the rooms with the conditioned air is all new and done correctly, replaced with the furnace a couple years ago. It was only the return duct (and the weird wall that it runs through) which is untouched.
I guess since they used the old return duct they didn't look for or find it being open to a space it shouldn't be. But in any case, thanks for confirming my suspicions!