three of four balance springs broken.

Thanks for writing in. Yes, the type of coil balance system you have could be the same for either single or double-hung windows. If you need certainteed hardware, then it's possible you have our 15-192 Pivot Shoe, which is compatible with Series 170 and Series 171 Coil Springs. But I'd love to see a picture of your pivot shoe just to be certain, as the identity of the pivot shoe confirms the identity of the coil balance system you need. Many thanks.