I have an upstairs room with an HVAC vent in the ceiling above the door. The return air is in the hallway just outside of the same door. This room also happens to be the hottest room in the house (by 5-10 degrees in the afternoon). I'm wondering if the duct location is incorrect? My theory is that the cold air is immediately sucked out of the room and never displaces the warm air in the room. Would moving the duct to the other side of the room make a difference in this case?

  • Try covering the return with one of those magnetic vent covers and see if the problem persists. Jul 8, 2011 at 10:47
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    @msemack, I'd have to disagree with covering the return. Assuming the home only has one return upstairs, how would you get the hot air out with the return covered? And if it's the only return for that HVAC unit, then you just severed the flow of air, possibly resulting in a large block of ice forming on the coils.
    – BMitch
    Jul 8, 2011 at 12:19
  • If there is only one return upstairs, then it is probably a badly designed HVAC system. There should be multiple returns, one in any room that will have the door shut for an extended period of time (e.g. a bedroom). But yes, choking return air completely is a bad idea, and I wouldn't reccomend leaving the return covered permanently, just for a day or 2 as a test. Jul 8, 2011 at 12:29
  • There are three returns (one upstairs and two downstairs). Covering the return sounds sketchy. Definitely going to try those covers. Jul 8, 2011 at 17:20
  • @msemack, I guess I've been dealing with older and city homes too much, most HVAC installs I've seen have one return per floor. And if the floor has a dedicated HVAC unit, then that means only one return. I can see the benefits of having more returns, since I can't sleep with my bedroom door closed.
    – BMitch
    Jul 10, 2011 at 1:38

2 Answers 2


I'm not a HVAC engineer, but your reasoning and theory sound good and well thought out to me.

I strongly believe (until I'm proven wrong) that moving the vent to the other side of the room would make a (noticeable) difference to the room's overall temperature during the warmer months.

Does the same duct-work heat your home during the winter months?

If yes, you will also want to take that into account when repositioning the vent.


Make sure you're adjusting the vents in the other room so that the coolest rooms receive the least air from the HVAC. Then, as a quick and easy test, try installing a vent deflector that attaches with magnets to push the cool air across the ceiling and into the room, rather than blowing straight down and out the door.

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