window balances, tilt in double hung windows approx 40 years old.

Question

29" Series 600 Spiral Tilt Window Balance S600-29 I believe is what I need.
My windows use a 29" balance on the bottom sash, and a 27" balance on the top. I'm wondering if I could replace only 1 of the top sash balances, with the only objection to hold the window up. I never actually open the top windows....and of course I would replace both balances on the lower sash's....the ones I actually open.

Thank you in advance!! My 1st time changing these type balances, and nearly every one of them in the entire house is bad...Over 20 windows.
Barry

Jasmine · Accepted Answer

Hi Barry,

It does appear the S600-29 would be the correct replacement balance. You'll need to select the red tip option for the replacement.

It would be advised to replace both balances at once to ensure that they hold the same amount of tension. It is important to consider, if one is malfunctioning the other is soon to follow.

So, even if you barely use the window, the one time it is used the other balance could become damaged. It can also cause the newer one to wear out faster. That said, the choice to replace only one would be up to your discretion.