I have an old house where the previous owners painted/sealed a lot of these windows so they are non-functioning. I'm getting around to replacing them but all of the videos I see online seem to deal with regular double-hung windows and how to take the proper measurements after removing them. I'm not entirely sure how to measure/proceed with the particular windows I have. I do see that most of them are screwed in with screws inside of the glide channel.

For reference, these are the windows per Andersen's site and this is a reddit post that has a photo of the kind of window I'm talking about.

I'm assuming the correct thing to do would be to remove the entire window trim around the edges, remove any screws/nails holding it to the frame and pull the entire thing out then measure for the new window?

Like I mentioned, the windows are super old and shut pretty tight, I'm afraid trying to pull them open will cause the glass to shatter so I can't even follow the instructions on Andersen's site which aren't even all that comprehensive.

  • Don't know what kind of replacement windows you're after, but generally, you measure inside trim to inside trim (since you don't have to pull the trim to do that). Then you order the windows. Don't remove them until you have the replacements on hand. If you're in the Northern hemisphere, it's gonna be a tad chilly if you rip out the entire window to measure then leave gaping holes in your house while you wait for the new ones to arrive...
    – FreeMan
    Commented Jan 27 at 1:03
  • 4
    A razor blade and a flat prybar are a lot cheaper than replacement windows, but suit yourself. Painted shut is entirely fixable...
    – Ecnerwal
    Commented Jan 27 at 2:13
  • The measurements needed depend entirely on what type of replacement window(s) you choose. You could tear out back to rough opening and replace entirely; you could be using a "block frame" replacement, which can sit in the existing opening without old frame removal; you could use "retro-fit" flanged replacements, which sit in existing frame but have a trim flange on the outside. This question cannot be answered without that information, and when you choose the new window type, the manufacturer will certainly provide direction (because they want to sell windows to you). Commented Jan 27 at 14:46
  • @Ecnerwal I'm aware that cutting the old caulk away is cheaper than replacing the windows. But the amount of heat the house would lose due to poorly insulated and inefficient windows (that would then have to be sealed up again to retain any sort of heat) kind of defeats the purpose. Commented Jan 27 at 15:25

1 Answer 1


You don't need to actually remove the window itself, just the trim so as to reveal the dimensions of the both the window and the rough opening (RO).

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