Coil Balance Spring for Certainted Double hung Window

Unfortunately, I'm not able to confirm the series of coil you need without first seeing the coil you have now. If you would like to send us over a photo of the coil and the pivot lock shoe it attaches you, we'd be happy to help further.

I'm afraid we don't have a 10 pound spring for this balance system. The 9 pound spring may work, but it will be a little weak.

Another solution would be to use two 5 pound springs. Specifically, our S170-405 on the bottom and an S171-405 on top. You'd also need a new 15-156 cover and 15-157 bushing. See what you think.

If you don't think the original springs were the right calibration, then you should weigh your sash on a scale and be 100% sure. That's the only way to know for sure that what you're buying will work. 

Once you have the exact weight of the sash, you simply divide it between the number of springs used to support it.

I hate guessing when it comes to balances. I've been personally burned too many times whenever I try. In my experience it's always better to know what you're dealing with and get the precise weight of the sash; measure  twice, cut once and all that.

Yes, okay then! If your window sash weighs 18 lbs, and assuming you're working with Series 170 Coil Springs, then (2) of the S170-409 will work for you.

Great! Always my pleasure to help. Let us know if you have any other questions. Thanks for your business, we really do appreciate it.

We are so happy to hear that everything has worked out for you. We look forward to working with you on your next project. 

That's awesome, thank you! We appreciate your kind words and look forward to hearing from you again. If you ever need anything else, you know where to find us.