Windows can be confusing to people who aren't familiar with their parts or construction. The window industry uses a variety of terms that aren't common knowledge to most people. Knowing these terms and basic construction information about windows can help you in the search for new windows.
Knowing what a window is made of and what basic window parts are called can help you when talking to window contractors and sales representatives at showrooms or in your home.
Here’s what every homeowner should know and what we will cover:
What Are the Basic Parts of a Window?
Windows can seem complicated, but at their core, they're made up of a few basic parts. The most basic window parts are discussed often when talking about construction and design.
- Frame. The frame provides support to the entire window, holding the other pieces in place. The frame consists of the jamb, head and sill (1).
- Sash. The sash is the part of the window that holds the glass in place. On double-hung and single-hung windows, sashes slide up and down to open and close the window. On casement windows, the sashes swing open.
- Panes. The window panes are the glass of the window. Panes connect to the sash and, in some cases, grid-like bars called muntins. Window panes can be single, double or triple for additional efficiency (2).
What Are Other Important Parts of A Window?
- Argon. Argon is the clear, non-toxic gas that is found between panes of glass to provide insulation.
- Balance. A balance is the device in the center of the window that balances the weight as the sash opens and closes.
- Casing. The casing is the decorative part of the window between the frame and the wall.
- Check rail. On a double-hung window, the check rail is the part of the window where the two sashes meet in the middle.
- Head. The head is the horizontal part of the window frame at the top of the window.
- Jamb. The jambs are the vertical parts of the window frame.
- Jambliner. The jambliner consists of strips that create a tight fit for the window sash.
- Lift. The lift makes it possible to raise a window in a single or double-hung window.
- Mullion. The mullion is a structural piece that fits between two distinct but closely spaced windows. Mullions can be horizontal or vertical.
- Muntins. Muntins are the wooden pieces that divide panes of glass within the sash. Muntins give the window a grid-like appearance.
- Sash lock. The sash lock is a part that is found on a double or single-hung window. The sash lock prevents the sash from rattling in its frame.
- Stool. Stool is another word for the sill part of the window frame.
- Vinyl. Vinyl is the synthetic material used to make the majority of windows. Specifically, vinyl is comprised of extruded rigid PVC.
While this list is not comprehensive of all the many parts, fillings and pieces to a window; these are the terms that homeowners should be familiar with and become part of the routine health check of a window (6).
How is a Window Installed?
A window is constructed off site and delivered to a home or building where it will be installed. The rough opening where the window is to be installed is covered in plastic sheeting (7).
In some cases, an old window must be removed before a new window can be installed. Older windows may have window weights that will need to be cut and removed. When new windows are installed, shims are used to level the frame before it's stapled or nailed into place.
Here are the main steps to installing a window (8):
- Remove Window Trim and Casing
- Remove Old Window
- Prep/Repair New Window Opening
- Inspect/Replace Window Stop
- Dry Fit Window
- Install Window
- Add Insulation
- Add Extension Jambs and Trim Molding
- Paint and Add Finishing Touches
Typically, window companies will take multiple days to remove and replace all windows. Hopefully your window company will remove only the windows they can install replacements for in one day, so your home will not have boarded up windows overnight.
Work with the project foreman when determining the timeline for your window replacement. If you are uncomfortable with your window company boarding up your window overnight, let your foreman know.
A Diagram of a Window
Different types of windows have different features. For example, double-hung and single-hung windows have a lift feature that enables the homeowner to lift the sash up to open the window, but a casement window opens outward with a crank.
Looking at a picture of a window, you'll see the casing around the very outside of the window. Just inside the casing is the frame, which extends all the way around the window and abuts with the sash.
The sash connects to the glazing, also known as the glass or panes. A simple putty, called glazing compound, helps hold the window glass into place.
Nearly all windows have locks of some kind, so when viewing windows, take a look at each lock or latch that is designed to hold it.
If you're thinking about purchasing windows for your home, investigate different window diagrams to see all the parts of each window style.
Are you Ready to Shop for Windows?
If you're in the process of shopping for windows, pay special attention to window materials and craftsmanship. See the windows in person before making a final decision.
While it's useful to look at diagrams online to get a sense of what each type of window looks like, craftsmanship can only come through when viewing the window in person.
Whether the windows are made of vinyl or wood, pay attention to how well the window slides open or closed, and discover if the lock is easy to use.