Series 180 Coil Balance Quote

Thanks for posting. If you are certain you have Series 180 Coil Balance springs, and the sash weighs 13.4 pounds, use the S180-07 7 pound springs, one on each side of the sash. This will give you a total support of 14 pounds, which is close enough to the exact sash weight. Let me know if you have further quesitons.