Prime Line Products H 3579 Wood Sash Balance 8 Lb

Product Description

The PRIME LINE PRODUCTS H 3579 is a wood window sash balance engineered to offset the weight of a single sash up to 8 pounds, or up to 16 pounds when installed in pairs on both sides of the window frame. Built with all-steel construction, the unit uses an internal coil spring that retracts aircraft-grade cable lifters to counterbalance the sash and hold it in the open position. The balance fits into a pocket measuring 3.25 inches by 6.375 inches, mortised approximately 2 inches above the centerline of the window frame. This part is installed by glaziers, general contractors, and maintenance technicians performing window hardware restoration or renovation work.

This sash balance is suited for residential wood-frame window applications where the existing balance springs have fatigued, broken, or lost tension over time. The H 3579 has been used across a wide range of wood window manufacturers and window generations, making it a common go-to replacement in multi-unit residential buildings, older homes, and commercial renovation projects. It is sold in a package of 5 units, allowing technicians to service multiple windows in a single job.

Key Features

• Supports up to 8 pounds per unit, or 16 pounds when used in pairs
• All-steel construction for durability in high-cycle residential applications
• Internal coil spring retracts aircraft cable lifters to hold sash in open position
• Fits a 3.25-inch by 6.375-inch mortised pocket, set 2 inches above frame centerline
• Package of 5 units supports multi-window service calls
• Compatible with a broad range of wood window frame designs across multiple manufacturers

Compatibility

Designed as a replacement sash balance for wood-frame windows using a 3.25-inch by 6.375-inch mortised pocket positioned approximately 2 inches above the centerline of the window frame. This style has been used by a variety of window manufacturers across many decades of residential construction.

Installation Notes

Installation is typically performed by a glazier, window technician, or experienced maintenance professional. Before servicing, ensure the sash is fully lowered and secured to prevent uncontrolled movement during balance removal. Use appropriate hand tools to access the mortised pocket and seat the replacement balance firmly before reconnecting the cable to the sash. Follow all applicable local building codes and manufacturer guidelines when servicing window hardware in occupied structures.