The Parts of a Window

October 10, 2019



The Parts of a Window - Clera Windows + Doors

There are a variety of parts that make up a window’s anatomy. Unless you are a window installer, you most likely do not know what they are. However, it is highly recommended that you familiarize yourself with the correct window terminology before you decide to go shopping for replacement windows. This way you can easily figure out and communicate exactly what it is that you are looking for when having them installed.

In order to find the best windows in Ottawa, we have devised a list of some of the most important parts of a window’s anatomy for you to learn. So, without further ado, let’s jump right in!

Most Important Parts Of A Window’s Anatomy - Clera Windows + Doors


This is the window’s frame or the moulding that surrounds all four sides of the window. A window casing can be made from a variety of materials, including vinyl, wood, and aluminum. It can come in many different styles as well. It covers the space between the window and the wall in order to provide a more clean and finished look.


What this refers to is the glass within the window frame. Glazing comes in a variety of options, including single, double, or triple thickness. What this means is how thick the air space between the panes of glass is. In general, double or triple glazing are the most energy-efficient options and will keep your home better insulated, no matter the weather outside.


The sash makes up the frame surrounding the perimeter of the window’s glass insert(s). It is comprised of two main parts; the rails and stiles. The rails are the horizontal part of the sash and help hold the glass in place with the support of the vertical stiles. On a double-hung window, there is an upper and a lower sash.


Muntins are the grids over the glass that you typically see in windows. The sections they create are often referred to as “lights”. They can either be completely decorative or serve the purpose of helping to hold the glass in place, although they are sometimes not included in a window’s design. They can also be installed on the inside, the outside, or even both.


This part of a window extends out, almost like a shelf, from the bottom of the window and into your home’s interior. You may be thinking that the sill also protrudes out on the exterior side of the window as well. You would be right, however, this part of the window is referred to as a stool.


Right underneath the sill, there is typically a board attached horizontally onto the wall—this is called an apron. It is completely decorative as its purpose if to accentuate the look of a window inside your home like you would with moulding.


The window jambs are the part of the window that holds the sash in place. They are located on the interior perimeter of a window’s casing. One of the areas of a window where drafts are typically found is between the window frame and the jamb. The best time to insulate your window is during the installation process of replacement windows so you can access the space between the wall and the jamb.

Crank Operator

Casement and awning windows open and close by swinging outward, either horizontally or vertically. However, to do so, they require an operator. These are mechanisms that you hand crank in order to operate.

Extension Arm

Also called a scissor arm, the extension arm is the device that extends or contracts when you use the operator to open or close a window. It is a vital component of the operator mechanism.


As you might have guessed, a window latch is the device that has the ability to lock a window. On a double-hung window, it is usually attached where two rails meet. It can also be attached on the stiles of a casement window, or the bottom rail of an awning window. In addition to providing your window with its necessary safety, it also acts to help the window seal properly. This will prevent warm/cold air from escaping your home.

The Best Windows in Ottawa

Now that you know your stuff, it is time to start looking for some replacement windows!

For the best windows in Ottawa and the surrounding area, considering Clera Windows + Doors. We offer an extensive array of windows for your home in a variety of styles, such as the following:

To find out more about Clera’s best windows in Ottawa, contact us today!

Related Articles