Window Balances 101: Parts and Repair | Brennan Enterprises

Window Balances 101: Replacements, Types, and Where to Buy Them

A primary reason homeowners replace their windows is because there are windows in their homes that don't open easily or stay open. The most common cause of these problems is a defunct window balance. 

Read on to discover why window balances are important and how they might influence your replacement window decision.

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What Are Window Balances?

Blue neon sign of the words open closed and open on a black background

A window balance is a mechanism that allows your single-hung and double-hung windows to open and close smoothly. The balance counters the force of gravity and holds the sash of your window unit in place. 

A sash is the part of the window that holds the glass within the mainframe of the window. Single-hung and double-hung windows operate vertically; without a counterbalance, the sash would fall to the bottom of the frame. 

The window balance is located in the window jamb, which is the vertical sides of the window. 

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What Type of Windows Have Balance Systems?

Window balances are only found in windows that move up and down, referred to as either single or double-hung windows. The balance mechanism helps you open your windows vertically countering the force of gravity. 

You won’t find window balances in horizontal sliders because this type of window sits on a horizontal track and slides left or right to open. Casement and awning windows don’t need balances because they operate on hinges and are pushed out to open. 

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Types of Window Balances

There are several types of window balances, the type of window balance found in your windows depends on the age of the window and the manufacturer. Like the rest of the window system, balances have become more sophisticated thanks to modern technology. 

There are four common window balances found in residential windows. We’ll introduce them to you from the oldest to the newest.

Cord and Weight

The cord and weight balance system was the first type of balance system installed in sash windows. If your home has older wood windows they may operate with a cord and weight or chain and weight balance system. 

Fun Fact: Prior to the invention of this counterbalance system, the operable sash had to be propped open with sticks, hinge systems, or swivel blocks

How do cord and weight window balance systems work? 

Windows with cord and weight balance systems have a box built into each side of the window (the jambs) where cast iron or lead weights are suspended. The weights are attached to a cotton cord which extends up the jamb, over a pulley, and onto the operable sash. 

In order to counterbalance the weight of the window, the weight in the jambs has to match the weight of the sash. Equal weight creates a perfect balance and allows the window sash to move smoothly. 

Double-hung window with weight and pulley system for each sash.
Image Credit: Old House Online


  • Nostalgia 


  • The cotton cords fray or break and eventually have to be replaced
  • The window sash must be completely removed from the opening to replace the balance system
  • It is challenging to find wood window repair technicians that do this sort of repair

Watch the video below for a look at a professional weight and cord balance repair from Fort Worth expert, Brent Hull

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How do spiral window balances work?

Spiral window balances are composed of a spiral rod and spring within a metal or plastic tube, they’re sometimes called a tube balance. Each side of the window sash is connected to the rod of the balance at the bottom corner. The spiral rod is rotated until the proper tension is achieved to smoothly raise and lower the window. Too much tension can make the window sash difficult to operate while too little tension will cause the sash to fall.

Like the weight and cord system, smooth operation is achieved through a perfect counterbalance (weight/tension). Unfortunately, the more you use the window the weaker the spring becomes. 

Image Credit: Uniquely Versatile


  • Simple design 
  • They take up less space allowing for more glass in the window opening


  • Can rust, dent, bend, and break
  • Can’t be repaired
  • Short lifespan compared to other balances

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Block and Tackle

The block and tackle window balance system followed the spiral balance system. Like all window technology, this system has seen improvements since it was first introduced. 

How do block and tackle window balances work?

The design of block and tackle balances is more complex than the weight and cord and spiral balance system. This system contains a series of pulleys and coil spring, in a sense it combines elements of both the previously discussed balance systems. 

The window sash in a block and tackle window is set into the jamb and is secured with a terminal clip and takeout clip. The top guide of the channel balance is tucked under the takeout clip and when the sash is placed into the jamb the balance moves with the sash. When lifting or lowering the window, the cords move through the pulleys providing just the right amount of stretch to the coil spring. Block and tackle balance systems for tilt windows have a similar design but also use a pivot shoe, learn more in our post Block and Tackle Window Balances Explained.

Image Credit: Prime-Line Catalog via Home Depot


  • Can handle heavyweight
  • Long-lasting system
  • Can be replaced


  • Window units with this system leave wiggle room for the sash so the seal is not as tight compared to windows with other balance systems

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Constant Force

How do constant force window balances work?

Constant force window balances work by using a stainless steel rolled coil spring. The spring is similar to a tape measure that extends and coils and, like other balance systems, it’s located in a pocket in the jamb. Manufacturers use a computer program to provide the perfect counterbalance for each window based on the window’s dimensions. The window’s dimensions determine the number of coils used in the balance system. 

The spring in this system should hold its tension forever, in fact, most windows with this balance offer lifetime parts warranty. This system doesn’t use cords that can wear and tear or parts that can rust. 

Image Credit: HomeRite Maryland


  • This balance system rarely breaks down
  • Usually covered by a lifetime parts warranty
  • The spring should never lose tension


  • We have yet to identify any drawbacks

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Can I Repair or Replace Window Balances?

If you can identify and source the original parts of your window balance, you can, potentially, replace it. To do so would require identifying the window manufacturer and series, the part # of the balance system, and secure a skilled technician to perform the replacement. 

If you can accomplish all of those things, the content below will walk you through the repairing process for each type of balance.

Repairing Cord and Weight Balance

If you have old wood windows, it’s likely that your home has a cord and weight balance system. 

For windows that move up and down and stay in place but are noisy you may just need to spray the pulleys with a lubricant. 

For windows that won’t open easily or stay up, you’ll have to access the pocket in the jamb to understand what the problem is. 

In most cases, the sash cord is degraded or torn which makes the repair fairly easy. Basically, all you have to do is replace the old cord with a new one. This Old House has a great video with step-by-step instructions on how to replace a sash cord on wood windows. 

If the weights are missing you’ll need to know the weight of the sash before searching for vintage replacements. Remember, the weights act as a counterbalance so the total weight of the counterbalance should equal the weight of the window sash that it will be lifting and lowering. Each weight should be half the weight of the sash.

Repairing Spiral Balance

For window systems with a spiral balance getting your window operating smoothly may just require an adjustment to the tension in the spring. To adjust the tension in the spring you’ll need a spiral balance tensioning tool. Remove the sash from the window frame and hook the tensioning tool to the bottom of the spring rod. The hook allows you to spin the rod and tighten the spring to the needed tension. 

You can’t repair a broken spring. If this is the case with your window, you’ll need to replace the spring balance and it would be good to replace both balances so that they are both in new condition. I would only recommend attempting to replace the balance if the rest of the window is in great shape, if the window is old and not efficient, it’s probably best to replace the entire window unit. 

Repairing Block and Tackle Balance

If your window is difficult to open, before taking it apart try spraying some lubrication into the jamb channel. Try sliding the window open after adding lubrication, if it’s still difficult to open you’ll need to remove the sash to access the balance and identify the problem. 

To remove the sash:

  1. Lift and flip the clips located in the top part of the inside jamb.
  2. Lift the sash up, over and past the clips. When you do this the balances will catch on the clip and release from the sash.
  3. Push the window in one direction and then swing the sash out toward you to remove it from the pocket of the jamb.
  4. The balance should be visible now, detach it from the jamb to inspect its condition

Once you detach the balance you can see if there is debris in the balance box, if it needs lubrication, or if something is broken. If the cord is broken you can try to find a replacement and re-thread it through the pulleys in the system. You can also try to find a replacement balance by using the numbers located on the outside of the balance. 

Repairing Constant Force Balance

Constant force balance systems seem to be the most durable balances we’ve seen thus far. This balance uses a stainless steel coil system that is encased and operates like a tape measure. Because of its design, the constant force balance system is unlikely to run into the same problems that systems with springs and cords run into. 

Our Brennan Traditions and Brennan Signature hung windows operate with constant force balance systems and come standard with a lifetime parts warranty. In fact, most window manufacturers who use this type of balance are so confident in the durability of the system they include a lifetime parts warranty.

If your constant force balance does happen to stop working you’ll have to replace the balance system which is fairly easy to do.

To replace the constant force balance:

  1. First remove the sash.
  2. Unlock the shoe and guide it up the jamb track. 
  3. Install a new balance with the same tension at the same level as the old system. 
  4. Lower the shoe down the jamb track and lock it into place
  5. Reinstall the sash to finish. 

Why Repair Can Be A Challenge

In order to operate smoothly the window sash requires a precise counterweight, which means the best way to repair it is by using the original equipment. The easiest way to find the right replacement part is by knowing which window brand and model you have. Finding this information can be a challenge but you’ll need it to match the balance systems. 

Another challenge is locating the source of the original balance. Because of mergers and acquisitions within the balance industry there used to be 12-15 manufacturers and now there are 4 big players. It’s also difficult to find laborers who are skilled in these systems. For some homeowners, the time and money spent to replace a damaged or broken balance system could be better spent on a new, more efficient product. 

Think of it this way, would you repair your computer from 1990 or buy a new one? If the product has historical value it may be worth the repair but if that isn’t the case something new is the better option.

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What Is the Most Popular Window Balance?

Currently, all of the window vendors we work with use either constant force balance systems or block and tackle balance systems in their window units. Some manufacturers use different types of systems depending on the window collection. 

It seems each balance system we’ve covered in this post has had its season. Cord and weight balances were used for well into the 1940s and -50s. In the 1970s and -80s spiral balances were popular but they weren’t as durable so manufacturers developed other solutions. Constant force balances are the newest type of balance and currently both constant force and block and tackle systems are popular choices for window manufacturers. 

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What is the Best Window Balance System?

Our choice for best window balance is the constant force window balance. The stainless steel coil system was absolutely designed with durability in mind. The stainless steel material won’t rust and because it’s encased, it’s unlikely to capture debris within the coil or overextend. 

In our showroom, you can see and touch the windows that we offer. One thing that our visitors notice is the difference in how smoothly some windows operate compared to others. Without a doubt, the windows with constant force balance systems are easier to operate and feel more secure than those with block and tackle balances. 

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Where Can I Buy Window Balances?

There are vendors that specialize in window balances, you can purchase directly for them or talk to the manufacturer of your window. We’ve compiled a small list of companies to help you in your search for replacement window balances and parts. 

If you know who the manufacturer of your window is, find the company website and contact them for assistance first. The parts you are looking for may be covered by a warranty. 


Prime-Line is a leading hardware manufacturer and supplier. This company sells parts for spiral balances and block and tackle (channel) balances. 

Prime-Line products are sold at leading hardware stores like Home Depot, Lowes, Menards, and Ace Hardware. While individual stores don’t carry all of Prime-Lines products, they do have access to the full catalog and can order what you need. carries spiral, block and tackle, and constant force balance systems. Their website is easy to navigate and includes graphics of all the products they offer.
Sells direct to homeowners.


Swisco sells all kinds of replacement hardware. You’ll find whole balance systems and small individual parts (“accessories”) in their catalog.
Sells direct to homeowners.


Amsco is actually the parent company of seems to carry more options but if you’re struggling to find a part, try Amsco as well.
Sells direct to homeowners.

All About Doors and Windows

All About Doors and Windows sells parts for block and tackle (channel) balances. You’ll find parts and with their prices clearly labeled on this website.
Sells direct to homeowners.

Blaine Hardware

Blaine Hardware can help you identify your window balance and provide you with pricing before shipping the product to your home.
Sells direct to homeowners.

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There you have it, a deep dive into window balance systems. If you’ve been struggling to lift or close your windows, we hope this post has helped you identify the problem and possible solutions.


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