Andersen window balance

A home owner from Howell, MI says:
I've decided to replace the broken window balance on some of our Andersen windows thanks to your instructional video. So thanks for that...I think. So quick question, is there any way to tell which balance is required without taking the window apart first? The windows, I believe, were installed when this house was built in 1984. I've attached some pictures but don't know if they'll be of any help. Thanks in-advance for any guidance you can give me. And thanks again for the instructional video.

Tom B.
Profile picture of Paul
Paul from SWISCO responded:
If you give me the width and height of the visible glass for both the bottom and top sash (separately), I can make an educated guess. It won't be as reliable as knowing what's printed on your balance, though.
A quick learner from Howell, MI says:
I decided to quit being lazy and take a look at the balance. I've attached pictures of the balance. The windows have a wood frame and the glass, upper and lower, is 32" wide x 24" high. Thanks for your quick response and help Paul.
User submitted photos of an Anderson balance.
Profile picture of Tom
Tom from SWISCO responded:
Perfect! I recommend our 24-939. This can replace Andersen balance boxes stamped with 9#27.
A quick learner from Howell, MI says:
Thanks for the recommendation. I ordered and installed the parts on two windows and they work perfectly.

I'd appreciate another recommendation for windows that are 40" wide x 24" high. The balance is labeled 12#31. Thanks Tom.
Profile picture of Tom
Tom from SWISCO responded:
Awesome! Glad it worked. For this other window, I recommend our 24-1231. This is for balances stamped with, of course, 12#31.
Reply to Thread
Use this form to ask a follow-up question or to share your experience regarding this subject.
(your email address will be kept private and is only used to inform you when a response has been made)
Current wait time is 4-7 business days
We promise that one of our experts will personally get back to you as soon as they are able. Thank you very much for your patience and understanding. If your inquiry is time-sensitive, please feel free to reach us at 856-317-6263 or at