We live in the desert where it's quite hot. We have a 2 story with central a/c with seperate units for bottom and top floors. While the a/c was off i noticed what felt like hot air from the second floor a/c intake. I went into the attic where i could look down between the walls and saw that the intake, which I suppose is supposed to fit up agains the wall, has about a 5" gap around it that exposes it to air in the attic, which is quite hot.
You can see in the pictures the gap between the intake and the wall. One picture is taken from the attic looking down on the intake from the wall where you can see the gap. The other is
This doens't seem right to me, as my assumption is that the intake is pulling in hot air from the attic which is making it difficult to cool the recirculated air. I was thinking of purchasing large chunks of foam insulation to fill the gap between the wall and the intake. I figured I should get advise before I do this though, because a lot of a/c issues aren't always intuitive to me. So, is there any reason that this gap is supposed to be there? Would it probably we helpful if filled in the gap?
I also noticed that for this same unit there's an intake in the unfinished garage, but with no output vent into the garage. You can see that in the bottom picture. The previous owner of the house covered it with a piece of cardboard as you can see from the picture. Is there a reason the origional a/c installer would put an intake into a hot garage, especially considering there is no a/c vent into the same garage?