Cold Air Register Sizing


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Old 01-06-15, 01:44 PM
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Cold Air Register Sizing

So I have a question regarding the sizing of cold air return registers. I've got 32x8ish return register in my office in the house. The register is lowish to the ground (maybe 6" above the floor). The return uses the wall cavity between the drywall as the "duct" to get the air to the basement. The wall cavity is only 1.75" (the width of a 2x4) so why does the cold air return need to be 4" tall. It seems like that is oversized given that the "duct" is only 1.75" wide. Am I missing some physics fundamental here?

I ask because I am thinking about moving the duct down and putting it into a toekick as part of a built in shelving system on that wall.
 
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Old 01-06-15, 01:59 PM
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Most 2 x 4 wall cavities are 3.5" or so deep. Is your wall cavity created with the 2x4 turned sideways (1.5")? If you currently have 1.75" x something less than 14.5" for the return, then that issue should be addressed. Total return ducts should be larger than total supply to avoid pressurizing the room.

Bud
 
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Old 01-06-15, 02:02 PM
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Duh. I'm an idiot. It's 3.5". *smacks self in forehead*
 
  #4  
Old 01-06-15, 03:41 PM
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Wait until you get to be my age, it gets worse .

Bud
 
 

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