Choosing the right balance spring for a single-hung window ensures reliable lift, smooth sash movement, and long-term durability. This guide focuses on high-quality options used in tilt and non-tilt installations, emphasizing constant-force designs, easy installation, and compatibility with common window channels. The selected products cover single-coil and tandem coil configurations to meet different sash weights and window types. Review the buying considerations below to identify the best match for your windows and budget.
| Product | Brand | Best Use Case |
|---|---|---|
| WRS Series 37 QuickTilt Coil Spring Window Balance | WRS | Tilt-style single/double-hung windows; mid-weight sash |
| WRS Caldwell Series 300 Block & Tackle Window Balance | WRS | Non-tilt side-load windows; light to mid-weight sash |
| CWH – 5/8” Tilt Balance 29 Inch | COTTONWOOD HARDWARE | Tilt-style sash; mid-weight to heavier load |
| WRS Caldwell Series 300 Block & Tackle Window Balance (28″) | WRS | Non-tilt side-load windows; mid-weight to heavier sash |
| WRS Series 37 QuickTilt Tandem Coil Spring Window Balance | WRS | Tilt-style windows needing extra lifting power |
WRS Series 37 QuickTilt Coil Spring Balance – Left & Right Hand
Designed for tilt-style single-hung and double-hung windows, this QuickTilt balance uses a single coil to deliver precise counterbalance and smooth sash travel. The set includes one Left Hand and one Right Hand coil, each rated to support 19–20.99 lb sashes, ensuring balanced lift when installed as a pair. The compact constant-force design offers quiet, friction-free movement and extends component life. Crafted from galvanized steel, it is built to resist corrosion and tested for thousands of open-close cycles, with a coil housing width of 1-9/32″ and a 17/32″ coil for a precise fit. This balance pair provides a reliable solution for mid-weight sash lifting.
WRS Caldwell Series 300 Block & Tackle Window Balance
Engineered for non-tilt windows, this 5/8″ channel balance is 29″ long and supports 16–23 lb sashes. It arrives pre-assembled with top and bottom guides for fast installation and does not include extras or hardware. The Series 300 line covers a broad range of lengths (8″ to 49″) and weight ratings (3–44 lb range), offering versatility for various vinyl and aluminum frames. Its smooth pulley and spring system helps prevent sash slams and sticks, delivering reliable operation in homes, schools, and offices. Sold individually, customers should verify compatibility with their window model before purchase.
CWH – 5/8” Tilt Balance 29 Inch
This 29-inch tilt balance features a blue 5/8″ spiral balance bearing and a 9/16″ tube diameter. It is designed to support 20–30 lb sashes per pair, with color-coded tips to indicate carrying capacity. Balance identification is aided by the tube length, tip color, and spiral end style. The CWH tilt balance line accommodates multiple window types with two common diameters (3/8″ and 5/8″) and is color-coded for carrying capacity, enabling easier matching to existing hardware. The product comes with guidance to help customers select the correct balance for their tilt windows.
WRS Caldwell Series 300 Block & Tackle Window Balance (28″)
Engineered for non-tilt windows, this 28″ balance supports 20–26 lb sashes and ships with top and bottom guides attached for straightforward installation. The Series 300 line covers a wide range of lengths from 8″ to 49″ and is designed for reliable, quiet operation in residential and commercial settings. It balances the sash to prevent slamming or sticking, maintaining windows at any height. As with other non-tilt balances, product specifics and compatibility should be confirmed with the window manufacturer to ensure correct fit.
26-4 2640 Window Balance Spring Replacement
This replacement balance is sized 26-4, with an overall length of 28″ including guides and a 27″ channel length. It is designed to support 19–26 lb sashes per pair and ships with installation instructions to facilitate a quick swap. The Cottonwood hardware offers winged end brackets for stable operation and smoother slides. The description emphasizes careful identification by stamped numbers and notes compatibility with a broad range of window brands, making it a practical option for retrofit projects.
WRS Series 37 QuickTilt Tandem Coil Spring Balance
Designed for mid-weight tilt-style windows, this tandem coil balance uses dual constant-force springs to deliver stronger lift and smoother travel. Rated for 21–22.99 lb sashes, it provides the benefits of a dual-coil system in a single assembly, enhancing lifting power while maintaining quiet operation. The tandem configuration reduces the risk of sash drift and improves balance across the window’s travel. As with other WRS products, it uses galvanized steel construction and undergoes rigorous testing to ensure longevity, with a compact housing that fits standard tilt window channels.
Buying Guide: Key Purchase Considerations
- Sash weight compatibility: Match the balance’s weight rating to your sash weight to avoid slippage or overworking the spring.
- Window type: Distinguish between tilt and non-tilt balances. Tilt balances often use pivot shoes and specific coil types; non-tilt balances prioritize channel compatibility.
- Coil configuration: Choose single-coil for lighter to mid-weight sashes and tandem coils when extra lifting force is needed.
- Channel compatibility: Verify channel width and diameter (5/8″ vs 3/8″ and tube diameter) to ensure a proper fit with your window frame.
- Installation: Look for pre-assembled guides and included hardware to simplify replacement; some products ship as a ready-to-install set.
- Durability and testing: Prioritize products with galvanized steel construction and AAMA-rated quality or equivalent reliability testing for long-term use.
- Replacement guidance: Some listings offer color-coded tips and clear identification cues to help you select the correct balance for your window model.
- Brand support: Consider brands with clear installation instructions and customer support for troubleshooting during retrofit projects.