Tom Shafer

Replace your broken window sash balance

July 13, 2012

How long have you been living with single- or double-hung windows you have to prop open with a stick? You could buy replacement windows and be done with the whole mess. But if it's only one window and you're not quite ready to take on your window replacement project yet, it's also possible to just replace the sash balance on that window.

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Removing the broken sash balance and installing a new one is not all that difficult. Identifying and purchasing the right one for your window might be the more challenging part of the repair.

Identifying the right replacement sash balance

If you know the manufacturer, model and size of your window, you have an advantage for locating the right part: contact the manufacturer. It is usually easier to install parts designed specifically for your make and model of window.

If you can't find the manufacturer, you'll need to figure out which type of sash balance your window uses. Balances can be identified by what happens when they're broken:

  1. Spiral balance. On spiral balances the helix (spiral) disconnects from the spring that attaches it to the tube in which it's housed. The balance loses tension, making the sash both hard to lift and difficult to stay open.
  2. Channel balance or block and tackle balance. Broken strings are the usual problem with this type of balance.
  3. Coil balance or constant force balance. These balances usually do not require replacement, but excessive dirt can cause the steel spring to deteriorate.

Spiral window sash balance Channel balance or block and tackle balance Constant force or coil window sash balance

Types of window sash balances (image credits: Swisco.com)

One good online source for these window replacement parts is SWISCO.com. If you need a spiral balance, for example, the site walks you through how to determine the specific type of tube, its diameter, length and even the method for attaching it to the shoe (the device connecting the sash and the balance).

Removing the old sash balance

To replace any of these balances, you first remove the sash, usually by tilting and raising one side until the sash pin disconnects from the shoe.

  • A spiral balance attaches to the window with a screw through the tube. Back out the screw, pull the tube away and disconnect it from the shoe.
  • The string on a block and tackle balance is the connection point with the window frame. Again, remove the screw; the balance and shoe should easily disengage.
  • The coils on a constant force balance are also accessed by removing the sash. A detent clip holds the coils in the window jamb. When the screws attaching the clip to the frame are taken out, the coils can easily be removed and changed.

Replacing sash balances is a relatively simple job for the do-it-yourselfer. If you order the right part, there is no reason you should have to endure windows that don't open or close with ease.

About the Author

Tom Shafer has decades of experience in window sales, marketing and product development. He's worked closely with window design engineers in testing, design, and building code interpretation. Past employers include United Windows and Doors and Norandex, MI Windows. He currently works at a home improvement retailer.

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