Everything You Need to Know About Window Sashes

Alison Kasch
Written by Alison Kasch
Updated April 21, 2022
Child playing near window
Photo: Catherine Falls Commercial / Getty Images

You’ve likely had your hands on a window sash, whether you realize it or not

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Most homeowners don’t spend a lot of time thinking about the mechanical workings of their windows. As long as they open, close, and keep the outside air out, and inside air in, most people are content not knowing the names of various parts of their windows or how they come together. If you’re having window troubles, though, or want to learn more about how to best maintain your windows, it can be valuable to learn a little more. Read on to find out everything you never knew you needed to know about window sashes. 

What Is a Window Sash and How Does It Work?

The window sash is the piece of interior framing that holds the glass and, on windows that opens, is used to push the window up or down. Located just inside the window frame, usually on tracks, this piece is important to both the appearance and the functionality of the window. 

Most standard home windows contain two sashes, one on the top and one on the bottom, and clasps that lock together to immobilize each. When the clasps are unlocked, the top sash is used to slide the top portion of the window down, and the bottom sash is used to slide the bottom of the window up. Window sashes slide using a set of cords and weights or spiral balances, which allows them to maintain a smooth, controlled movement as they open and close. 

Double-Hung Window Sashes

Most window sashes come in the double-hung style of window, where an upper window sash is above a lower sash. Both sashes remain parallel to one another, with the lower window sash able to slide up or down. In many newer windows, the upper sash can slide in either direction as well.

Casement Window Sashes

Unlike the double-hung window, which slides up and down, casement windows open and shut like a miniature French door. Most will operate with a crank, while a select few allow you to open or shut them with your hands.

Aside from the bonus arm workout, these types of window sashes have a few advantages:

  • They allow you to fully open the window, whereas double-hung windows only allow half at a time.

  • They provide superior airflow, with the open window sash helping to channel in more fresh air.

  • They allow for an obstruction-free viewing of your garden, kids, bird feeder, and all the other joys of your outdoor space (without the window sash meeting rail getting in the way).

If you’re interested in double-hung or casement window sashes, talk to a window replacement company near you to learn more.

Why Window Sashes Matter 

Mug sitting on white window sill
Photo: Natalie Board / EyeEm / Getty Images

The sash is an integral part of the window and contributes to your window being energy-efficient, air-tight, and leak-proof. Window sashes create a seal around the glass that helps prevent fogging in multi-pane windows and other issues in single-pane windows. Window sashes should be well-made and well-maintained to avoid distortion, gapping in the seal, or leaking moisture.

Window sashes that are broken or improperly maintained can cause all sorts of trouble for your windows and your home's interior. If you have a broken or damaged window sash, you may see your energy bills creeping up and will likely experience draftiness or moisture inside your home. 

Common Window Sash Repairs 

Like any part of your home, window sashes may need to be repaired from time to time. Homeowners with wooden windows may experience difficulty opening and closing their windows if the wooden sash swells with moisture or the changing of the season. This swelling and the resulting difficulty with opening and closing prompts many homeowners to replace their windows with vinyl, which eliminates the issue. 

If you notice fogging around your window sashes, you likely have a damaged seal. This can occur due to improper installation or general wear. If this happens a window repair company near you can help address the issue. 

How to Maintain Your Sash Windows

You’ll save future window repair costs if you inspect and maintain your windows regularly. Window sashes aren’t too demanding in the maintenance department, but do keep a keen eye if they’re made of wood. Otherwise, check your sashes every month or so for signs of mold, mildew, damage, and deterioration.

If your window sashes develop any problems, you don’t always have to front the cost for a complete window replacement. There are repair kits available that can have your sashes looking as good as new for a fraction of the price.

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