My understanding is that insulating inside of a window can lead to condensation problems on the outside (see answer to this question). I have been using insulating window film kits for a few years and have not noticed any damage like this? What are possible reasons for this? (Maybe I have simply not applied the film very well?)

1 Answer 1


Actually, that answer is talking about condensation on the inside of the window, between the glass and the fiberglass insulation.

But you didn't put up fiberglass insulation, which leaves an air gap next to the window. This is where the condensation happens.

On the other hand, you put up insulating film which sticks directly to the glass without an air gap. Thanks to the film, the inside surface doesn't get very cold so there is no (or very little) condensation.

You're fine.

  • Thanks DoxyLover! On second reading, of course you're right about the linked question. However, my plastic film is leaving an air gap between the plastic and the glass. Does that affect the answer?
    – capet
    Sep 28, 2020 at 13:15
  • @capet If it’s actually a film I cannot imagine there would be a gap. It’s got to be stuck to something to keep it up. In any case, if there is a gap, then unless the window is double-pain, the inside of the window will get close to the outside air temperature and you can get condensation.
    – DoxyLover
    Sep 29, 2020 at 0:34
  • You're right; it's affixed to the frame with double-sided tape like this. Do you have any idea how long (if at all) do you think it would take for me to observe significant water damage?
    – capet
    Sep 29, 2020 at 14:02

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.