Fix a Noisy HVAC Return Duct

May 31, 2013 | by Ethan (email) |

Does your HVAC return duct make noises when the air handler starts and stops? Does your return duct “buckle” from the increased pressure when the supply is active? If so, your return duct may be slightly undersized for the rest of the system. This was the case for me after replacing a few components, and after the swap, I could hear the ductwork when the unit kicked on or off. One perk of hanging with contractors on Pro-Follows is that I can get their advice, and fortunately it’s easy to fix a noisy HVAC return duct.


Pro HVAC contractors I spoke with recommended cutting an additional opening in my return duct. Some time ago, we removed a whole-house humidifier that was mounted to the return and covered the opening with sheet metal. After removing the screws and cutting through the mastic, I exchanged the sheet metal for a return vent grille. After that, I waited for the air to cycle on / off, and I was pleased to find that the noise was gone.

13 Responses
  1. Brady says:

    I’d be interested to hear ideas about how to quiet a loud supply. The supply to the master bedroom is directly above the air handler, which is directly behind one of the master bedroom walls. The supply vent’s proximity to the blower as well as a sharp 90° turn right before it exits into the room combine to make the noise level in the bedroom pretty high.

  2. Joe says:

    nice simple fix!

    I really need to have my entire system redone, my master bedroom is not getting enough airflow, and the basement gets too much in the summer (its already cool down there!!!)

    theoretically that should be done AFTER I refinish and properly insulate the basement. right now the insulation down there is non existent.

    • Joe says:

      I assume the basement is conditioned in your house, so you’re not sucking unconditioned air into the system constantly?

  3. supimeister says:

    What do you use for cutting your hvac?

  4. Something to consider: The return air ducts are designed to pull air from different parts of the house to help balance the system, moisture levels, and temperatures in that house. Putting a large hole in the main trunk is going to drastically lower it’s purpose.
    If you can locate the spot on the duct where it is flexing, you can stiffen the metal that keeps popping in and out.

  5. HANDYMAN51 says:

    Something to check for when purchasing a home, even if it can be fixed.

  6. Eek565 says:

    I love it when fixes are easy like this one. I know the opposite can be true too of exhaust fans. A lot of the time excess noise is because the ducts are too narrow.

  7. poiboybf says:

    Hmm interesting read. I haven’t noticed this with either of the returns in our house, but I’m not surprised given that ours looks gigantic. Something to look for for sure.

  8. trebor says:

    I have some minor noise when my AC or heat kicks in. It’s kind of a creaking in one spot along where I believe a duct is. It creaks and taps for a couple minutes and the best that I can figure out, it’s the ductwork expanding/shrinking to the temperature changes. Unfortunately, it’s located on the ceiling of a first floor room in a two story house so I can’t get a good look at it.

    I’m not very concerned about it as it seems minor; should I be?

  9. Genevieve says:


    Got a question. I have a really noisy return. I have had the ducts cleaned etc., but it made no difference. The return is in a small wall between the kitchen and the living room. When it kicks on you have to talk louder and turn up the TV. The same unit also pull from the bedroom but not as with nearly the amount of gusto or noise. I am rather sure the return is directly above the AC unit. Thought about increasing the face size of one or more of the returns to ease the pull, but not so sure that would work. Ideas?

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