Window Balance

A window balance is the counterweight or spring system that holds a double-hung or single-hung window sash in the open position. Without a functioning balance, the sash would fall closed under its own weight the moment you let go. In older homes, window balances were actual sash weights (cast iron blocks suspended by cords over pulleys). In modern windows, they are compact spring-loaded or block-and-tackle mechanisms installed within the window jamb channel.

Types of Window Balances

• Sash weight (rope & pulley) — found in pre-1950s homes; cast iron weights in wall pockets connected to sash by cotton or chain rope. When the rope breaks, the sash won’t stay up.
• Spiral balance (tube balance) — a coiled spring inside a metal tube; fits into a channel in the jamb. Common in vinyl and newer wood windows. Easy to replace.
• Block-and-tackle balance — uses a block-and-tackle pulley system inside a plastic cartridge. Provides smooth, consistent force across a wide range of sash weights.
• Constant force balance — uses a coiled flat spring; very smooth operation; found in premium windows.

Signs of a Failed Balance

• Sash falls closed when released
• Sash is very stiff or hard to lift
• Sash tilts to one side when raised
• Visible broken spring or disconnected cartridge

Balance Replacement

Window balance replacement is one of the most common and cost-effective window repairs. A professional can replace both balances in a standard double-hung window in 20–30 minutes. Cost: typically $75–$150 per window including parts.