What is a Window Sash?

A window sash is a small part of your window that surrounds and holds the glass and the frame in place. It’s typically made of wood, vinyl, or aluminum. It also has a handle that allows you to open and close the window.

Some window sashes are moveable, while others are stationary. The moveable ones allow the glass to slide up and down along its track. For example, a double-hung window features two moveable sashes, while single-hung windows have one moveable and one stationary sash.

What Does A Window Sash Look Like?

It can be challenging for some people to identify the part of their window that is the sash. It’s easy.


Look for the aluminum, wooden, or vinyl casing surrounding the glass on any standard double-hung or single-hung window. It’s the part that clings to the trucks and is stuck on the window frame.

Why Is A Window Sash Important?

Like all other parts of your window, the sash is integral in ensuring that the window functions correctly. For instance, it holds the glass in place and allows you to open and close the window.

It also contributes to window stability by holding the framings in place. This prevents it from rattling or moving when the winds are blowing hard.

Also, a properly-installed sash prevents air leakage and drafts around the window. It’s designed to be airtight, helping keep your home warm during winter and cool during summer. Even the moveable ones maintain a tight seal that contributes to the overall energy efficiency of your house.

So what makes them so effective? They come fitted with unique features that keep the air from coming in or out of your house. For instance, vinyl sashes have multi-chambers that prevent distortion. Without such features, your window can leak air and cause energy loss.

Finally, the sashes also play a role in improving the aesthetics of your window. They come in different designs and materials to match the look of your house. Not only do they make your windows secure, but they also give your home a touch of beauty.

How do Window Sashes work?

Window sashes consist of individual parts such as sash cords, counterweights, rails, pulleys, and wagtails. All these pieces come together to ensure that the window opens and closes smoothly.

Most of them are in the hollow lining of the window frame, thus remaining invisible most of the time. While you can’t always see them, they are the parts that ensure the smooth and seamless operation of your window.

Each window sash also comes with a horizontal board that redirects rainwater away from the window. This helps keep the glass dry and prevents mildew and rot.

When to Replace a Window Sash

Like everything else, window sashes don’t last forever. They will eventually wear out and need replacement. Signs that tell you it’s time for a replacement include:

  • They are no longer fixed in place and keep moving up and down
  • Signs of water leaks or drafts
  • A wooden sash has rot

While window sashes have a long service life, that doesn’t mean they won’t need repairs or replacements after a while. If you notice any problems, you should call a window replacement expert and check them.

How to Maintain the Window Sash

Generally, your window sashes don’t need regular maintenance. However, those made of wood need service. Their paint and sealant start to deteriorate after a while and need resealing.

An annual inspection service can help identify and prevent problems that might lead to costly repairs. It helps detect things like mildew, mold, scratches, and deterioration of the soft wood.

Contact Us Today

At Miller Window, we provide you with quality window services. Our team of experts can identify problems and give you the right solution to keep your windows functioning. Call us today at 386-775-2893 to request a free estimate.

Click to learn more about us.