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Types of duct insulation available

Jonny_H | Posted in Green Products and Materials on

When talking about building enclosure insulation, there’s so many choices — fiberglass, mineral wool, cellulose, half a dozen types of foam, wood fiber, cork, actual sheep wool, etc….  But, when it comes to insulating ductwork, it seems like there’s (maybe) three choices:  R-6 to R-8 fiberglass wrap, the bubblewrap stuff that’s better as packing material, and Armaflex rubber duct wrap (if you can find it).  Where are the alternate options when you want more R-value than what these products offer, or don’t want to use fiberglass from a materials perspective?

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Replies

  1. Walter Ahlgrim | | #1

    The smart move is to keep the duct work and equipment inside the conditioned space then insulating the ducts becomes almost irrelevant.

    Walta

    1. Jonny_H | | #3

      Almost irrelevant -- but some things (like HRV intake / exhaust ducting) would still need to be insulated. But, I fully agree with keeping things inside the conditioned area as much as possible.

  2. Expert Member
    Armando Cobo | | #2

    Per code, you need to sealed and insulate your ducts, with R8 in vented spaces, or R6 in unvented spaces. To avoid condensation in ducts in ventilated spaces for CZ1-3, the codes allows to double wrap the ducts with R13 min. (R8+R6). A good option is to encapsulate ducts in ventilated spaces with 2" ccSPF, and then pilling up CZ required insulation.
    Check the Building America Solution Center's details for almost every situation: https://basc.pnnl.gov/search?keywords=insulating+ducts
    I need to add that you can use duct board or phenolic duct (closed-cell rigid foam boards).

  3. Burninate | | #4

    Could you run a continuous soffit with centering baffles around the rigid/semirigid ductwork, and dump blown-in insulation around that?

    Or does insulating cold ductwork require something air & water-impervious like foam to avoid condensation?

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