Asked on Feb 16, 2018

Loud hvac air return. Loud blowing air and fan noise. How to fix?

by EL
is there something that can be placed inside
the air return box of hvac so that it can limit air and fan noise? It’s not a rattling noise.
its very loud air moving noise. Removing the
air return cover did not help. It sounds like a wind tunnel. Any product or advice to recommend? Thanks

  6 answers
  • William William on Feb 16, 2018
    If this has been an ongoing problem the system may be undersized. If it just happened recently: filter changed, all vents open, ductwork in good condition. Too many variables to determine with out diagnosing.

  • Homertalk Homertalk on Feb 16, 2018
    you can build a plywood box to fit over the unit, lined with eggcrates, or with insulation to deaden the sound. You can wrap the pipes through which the air moves with insulation and Tuck Tape. this will cut down the sound dramatically.

    • See 2 previous
    • RobC RobC on Aug 13, 2020

      In my home the air filters are located just inside of the two large return air registers. When I installed “better” (I.e. more restrictive) air filters, the noise from the air being pulled in increased dramatically to the point of being annoying. I also realized it was putting a large burden on the fan motor which was not designed to pull against that much of a restriction. I installed a less restrictive filter and brought the intake air noise down to an acceptable level. The manufacturers use a numbering system to rate their filters for efficiency (and hence restrictiveness). Most use the MERV# but Home Depot uses an FPR# and 3M uses an MPR#. They are different values but it is possible to convert between them (do a search on comparing them). Perhaps this info might help solve your problem. Good luck.

      Edit: This concept/issue would be the same for a filter installed right at the furnace as well. If the filter is too restrictive, the noise will travel back up the ducting to the intake vent producing the same problem.

  • Jules1960 Jules1960 on Feb 17, 2018
    You might want to see what level your fan speed is. Ours was set incorrectly, had the same problem. Hope this works. By the way, the technician set ours at auto.

    Also, clear all your outside vents. Perhaps something got into your vent.

  • 1240839 1240839 on Feb 18, 2018
    Isn't it supposed to have a filter behind the vent grill?

    • EL EL on Feb 18, 2018
      there already is a filter inside the return air box right near the unit

      i didn’t want to add another filter behind the grill for fear of restricted air flow

      can another filter be added behind the grill?
      would it quiet down after that?

      if so,what type of filter to use?

  • Jules1960 Jules1960 on Feb 18, 2018
    Glad the vents are clear.

  • 1240839 1240839 on Feb 19, 2018
    If it's supposed to there will be brackets to support filter. My mom's house had one on return grate and at the heat/AC unit itself.

    • See 1 previous
    • 1240839 1240839 on Feb 20, 2018
      Not sure. If it wasn't that way it might restrict airflow too much.