Coil balance for vinyl double hung window

Thanks for posting. I'm not sure exactly what's broken on your balance system, but it if it's just your coil springs then see our Series 180. I'm confident this is what you need. You'll have to get the number stamped on your existing springs to confirm what Series 180 option would be best.

If you need the other parts compatible with this spring, see our 15-087 pivot shoe/bottom housing, 15-086 top housing, and 16-024 bracket. 

Thanks for getting back to us. Looks like all your springs are stamped with "6#," which I believe is the most important number. This is the weight rating. The equivalent of this stamp would be our S180-6. 

If you use two springs per side, this will add up to 24 pounds of support. It's a pound less than your sash weight, but since your sash weight is an odd number this is probably as close as the installers could get. As long as your springs worked well in the past, then you can stick with this. 

Those other products you picked out are all related, yes, but keep in mind that you only need to replace those parts that have broken. You can reuse the rest.

Well, you don't want to go too strong, or else you'll find it difficult to close the sash. Personally speaking, I'd rather be one pound under weight than three pounds over. It's up to you.