Help needed: Andersen window replacement sash units

A home owner from Poughkeepsie NY says:

Hi. We have several windows in our home that require window sash replacement units. Andersen windows, as the strings have broken and windows will not stay in place. Original units installed 1987. I include two pictures.

The  actual window heights are 25" and 31". The window frames are 48" and 60" in height.

Width for both windows is 36".

Can you help identify the correct replacement kit's for us to purchase from you? Thanks!

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Bob from SWISCO responded:

Thanks for posting. Unfortunately the only reliable way to tell you what Andersen Sash Balances you need is to remove one of the boxes from each window and photograph all the stamped numbers on the balance box. It's these stamped numbers that indicate the balance box the window needs. For instance, you can replace the balance you have photographed above with our 24-1231. This is because that balance has the stamped number 12#31, or 1231; the 24-1231 is meant to replace balances with such a code. 

If you can provide us that information for each window that needs balance boxes replaced, we should be able tell you what you need.

A home owner from Poughkeepsie NY says:
Bob,
Thanks for your quick reply! For the unit shown in picture, I assume I need both a Left and Right version of the window sash replacement unit?
I will remove the smaller window in my home office and take/post a picture of that one too in this thread, to ensure I order proper replacement.
For other similar windows in my home, can I assume the replacement units are the SAME if the window dimensions are the same? All of the windows in question were originally installed in 1987.
Thanks again. With spring arriving eager to get these fixed (and remove the wood 2x4's I've been using in the interim.)
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Bob from SWISCO responded:

The 24-1231 is neutral-handed, so there's only one version for both sides of the sash. Some of the other Andersen sash boxes due come in different-handed versions, however. Ultimately the stamps will tell you which kind you need. 

If the other windows in the home are the same dimensions, to be honest, there is a good chance they are the same type of balances. That said, I have seen them be inexplicably different sometimes, which is why we always advise seeing pictures of the stamps just to be extra careful. Ultimately, it's up to you. I know taking these things out can be quite a hassle, especially compared to other kinds of window balances. If you want go for it, you can always return the balances if you find out when you take out the old balances that you don't have the replacements you need. See our Return Policy here. Just let us know, and happy to help you with your repairs. Thanks!

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Bob from SWISCO responded:

We are happy to have been able to help you with a replacement recommendation. Be sure to get back to us and let us know how everything worked out.

A quick learner from Poughkeepsie NY says:
Bob,
Thanks again for your expertise and advice! Ordered several 24-1231 replacement units today.
Will reach back to this forum and you with any further questions. Also, thanks to you and your team for posting a "how to" video on replacing these units!
How to replace an Andersen Window Balance
How to replace an Andersen Window Balance
VIDEO
WATCH >
Andersen's Narroline Sash Balances
Andersen's Narroline Sash Balances
GUIDE
READ >
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