I am interested in how denim insulation like this performs at low ambient temperatures. Does anyone know? I am most interested in performance measures like R-value and what other factors affect this.

I have seen some estimates for other materials, such as here and here, but not for denim or for other "fabric-type" insulation.

(For me, "low temperatures" means 0 to 40 deg F, or -18 to 4 deg C. I am thinking about insulating windows at night with denim insulation and a vapor barrier, but I'm interested in a range of applications.)


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    Two layers of air tight Poly with an air gap would do better to reduce frost draft and avoid frost with a 1cm strip Lok for adhering Poly around frame. even 1 layer of sealed 4” air shield would work far better than thin denim to avoid the convection Rth loss Sep 13, 2020 at 18:06
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    Will denim absorb moisture?
    – Solar Mike
    Sep 13, 2020 at 21:06
  • @Solar Mike I don't know, but I assume it wouldn't with a vapor barrier?
    – capet
    Sep 13, 2020 at 23:43

1 Answer 1


you can use this far better frost avoidance and cold draft reduction . good to -40’C


I made insert frames and heat shrunk onto then remove and store in spring. But getting an air flow seal is best. They will inflate if not tight. Easy to install with a hair dryer, not too close .(6”)

  • Thanks a lot, that's a great idea! I have a deep window; could I set up multiple "layers" of bubble wrap adhering to the interior faces of my window frame? Would that have any effect?
    – capet
    Sep 24, 2020 at 6:16
  • Another question: Could I do a variant of this by using two layers of shrink film, adhering the bubble wrap to the interior side of the exterior layer?
    – capet
    Sep 24, 2020 at 6:19
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    Heatshrink film is most attractive since it is transparent when stretched. heat stretches it evenly. Bubble wrap offers 2 layers, but if not air sealed air seal leaks will spoil the insulation value of air R=1. A large roll of Poly. Is the cheapest solution with 1” duct tape on wood. Sep 24, 2020 at 10:48
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    Looks good. Seal with good tape Sep 24, 2020 at 14:13
  • 1
    As long as it is airtight Sep 24, 2020 at 16:50

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