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Community and Q&A

Insulating duct work in conditioned space

Norman Bunn | Posted in Mechanicals on

I am planning to run the ducts for my HVAC in a conditioned basement and unvented crawlspace. The duct work will be metal except where branches might use well supported flex duct. Is there any reason to insulate this duct? Possible condensation during cooling season? If so, at what R value?

mixed humid zone 3, Greenville, SC

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  1. Expert Member
    Armando Cobo | | #1

    Yes, yes and R6 min.

  2. Steve Knapp CZ 3A Georgia | | #2

    It also is important to seal the duct with mastic to minimize air leakage.

  3. Anon3 | | #3

    Insulated ducts absorb noise.

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