Replacement Sash Balance

Question

I am looking to replace a window sash balance. Based on other posts I have seen, I tried to round up as much info as I could before posting. I believe that I need a 'S385-27 2660', but I wanted to check with the pros first.

My window is 46 1/16" wide by 29 13/16" tall. It is a single hung non-tilt sash window. The single pane when removed from the frame and placed on a scale weights approximately 33 lbs.

The current sash is labelled with the stamp '26 4 CALDWELL HM'. It measures 27" long from metal end to metal end, 1/2" wide, and 9/16" deep. The pictures below are of the shoe and top for the balance, along with the stamp.

Am I correct in my guestimate for the replacement part? Thanks.

User submitted photos of a window balance.

Paul · Accepted Answer

Thanks for posting! You are correct. For a 33 pound sash, you will need the 2660 option. However, it seems that the window manufacturer used 2640, which support 19 through 26 pounds. I wonder why that is. Did your window ever seem hard to open, like it was too heavy?