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  1. #1
    Join Date
    May 2013
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    Loud HVAC in residential units.

    I have metal circular duct work in our residential units. They are VERY loud. We have reduced the speed on the air handler and it helped a small amount but not enough.

    I have been given two suggestions I wanted to see if anyone had a opinion on;

    1. Insulate the duct work. I actually have seen this done in a renovated school project where the ducts were too loud and condensation occured. It worked perfect.

    2. Try DuctSox or some other inflatable duct system. I've read a few post on these and that does not seem to be a good solution.


  2. #2
    Join Date
    Jan 2009
    Saint Joseph, MI
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    You could try replacing a 8-10' section wit hthe same size flex. That's better that reducing airflow.

    The best solution is making sure the supply plenum has insulation/lagging in it. YOu similarly could insulate a 8-10' section of the main supply branches. Usually that's enough to cut the noise.

    I'm having a similar problem in my home with a fan powered humidifier. I'm going to replace a section of metal round duct with flex this fall. Should resolve the issue.

  3. #3
    Join Date
    Aug 2003
    Fort Worth, TX
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    I have modified all-metal residential ducting with noise complaints by replacing the take-offs from the main trunk with flex. Keep it straight, kink free, and seal all fine and greatly reduces noise.

    I have also found rhat straight electric heat and heat pump air handlers are the worst when it comes to all-metal ducting with no internal lining due to the blower being downstream from the coil. Gas furnaces with the coil downstream from the blower are considerably more quiet.
    Building Physics Rule #1: Hot flows to cold.

    Building Physics Rule #2:
    Higher air pressure moves toward lower air pressure

    Building Physics Rule #3:
    Higher moisture concentration moves toward lower moisture concentration.

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