35" Series 499 Spiral Balance

Question

I would like to replace Spiral Balances on condo windows. Some are sprung with the spiral part extending down the entire bottom of the window.

The prior owner said he bought 35" Series 400, but did not say which ones.

I removed a spiral balance which is definitely 35", 3/8", but there is no colored tip. This part is from 1971. I do not know how to remove the sash. They do not seem too heavy. Can I weigh it by putting a scale under an open window that has broken balances? It seems like that is the full weight of the window.

I was thinking of buying white tip for lighter windows.

I am dealing with 12 windows, 24 window spiral balances.
single pane aluminum frame windows
1971
No brand ID that I have located.

User submitted photos of a window balance.

Paul · Accepted Answer

Your sashes are made not to come out. Try putting a bathroom scale on the sill and weighing the sash. It's not perfect, but it should give you a good idea.