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Air return makes too much noise, what should I do?

21600 Views 15 Replies 4 Participants Last post by  bigburb
I have a 4 ton AC system with 2 16x25 returns. One is located directly under the AC and is attached to the plenum, the other is located about 15 feet away and is attached via about a 10" duct. The closer one makes a lot of noise and catches most of the dust... the farther one has hardly any suction (I can usually go about 6 months b/t filter changes). I know I need to get more filter area somehow, I had three theories on what to do, but would like input:

1. Enlarge the current opening to 16x32, this would yield 175 sq in more intake space.
2. The chase directly under the plenum is on a hallway corner, I could install another 12x24 return grill on the adjacent wall that would yield 288 sq in. However I wasn't sure if it would be "aesthetically pleasing" to have a return on either side of a corner.
3. I can enlarge the return duct from the furthest chase to 12", I'm not sure if this would have enough effect to make a difference though.
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Return duct

Hi !

Your existing ducts are 16x25 (400 square inches).if you use 2" insulation inside the duct,you'll end up with only 12x21 (252 square inches).

I would keep the other duct work.
Noisy duct work

Hi !

In order to reduce the noise coming from the duct work or to get ride of it ,you must line the inside of the duct with the proper insulation.

Many time on commercial job site we have to do the first 10 feet coming from the unit or sometime the whole duct work system.

If an engineer ask for the duct work to be lined with accoustic and the dimension is 14 x 23,we have to make the duct work 16 x 25 for 1" accoustic lining.

You'll see a world of difference lining the inside.If you do the outside I am pretty sure you are waqsting your time and money.

Glad I could help.
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