GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

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?

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  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.


    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:
    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?

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |