Window Balance
A window balance is the mechanism inside a single- or double-hung window that supports the weight of the sash. It makes the sash easier to raise and helps hold it in position.
Common Types of Window Balances
Block and Tackle: Uses springs, cords and pulleys to counterbalance the sash.
Constant Force: Uses a coiled stainless-steel spring that provides consistent tension with relatively few moving parts.
Spiral: Uses a spiral rod or tube and spring. It is common in many older windows and is still used in some current designs.
Typical Service Life
As a general guide, block-and-tackle balances may last roughly 15–30 years, constant-force balances 20–30+ years, and spiral balances 10–20+ years. Actual life varies with sash weight, frequency of use, hardware quality and environment.
Signs of a Balance Problem
The sash will not stay open.
The sash drops unexpectedly.
The window feels unusually heavy.
One side sits higher than the other.
The window makes unusual noises when operated.
Can It Be Replaced?
Usually. The correct balance type, length and weight rating must be matched to the sash.