What Are The Different Parts Of A Casement Window?

Do you want to have casement windows installed in your home? Do you know what their different parts are called? If you're curious, read on because we've researched so you can get to know your casement window better. With that said, let's dive in!

A casement window has two main components: the window frame and the casement.

  • The window frame includes the head, sill, and jambs.
  • The casement is made up of the top and bottom rails and stiles.
  • The mullion and transom are also connected to the window frame.
  • The casement window has other components such as a fanlight, casing, crank operator, and aluminum clad.

Keep reading to find out where these parts are located within the casement window and other terms you need to know when discussing your window project. Let's begin!

Casement Windows Explained

Collection of isolated window frames

Windows are an essential part of the house. They let in light and air, so the house doesn't look gloomy or feel stuffy. They also provide an opening for you to see your outdoor area inside your home.

Therefore, windows play a big part in setting the ambiance and mood and add to the beauty of your interiors. There are different kinds of windows to choose from.

Each window type offers a different form and functionality. Today, we'll focus on casement windows. These are one of the most popular window types in the market, and we'll find out why.

They are commonly used among contemporary, traditional, and modern houses because of their flexible and versatile style.

Specifically, casement windows are those windows that have hinges on one side. They can be opened either to the right or left side with a crank or lever.

When closed, the casement locks tightly against the window frame, sealing the window opening so that no air can get in or out of the house.

It is helpful to know the different parts of a casement window so that you won't get confused with the terms, especially when talking to your window dealer or contractor about window installation and replacement.

So, let's cover the anatomy of a casement window below:

Anatomy Of A Casement Window

The casement window comprises two major parts: the window frame and the casement. Other components make up this window type.

Window Frame

This refers to the bars running along the perimeter of the window. It includes the top (head), sides (jambs), and bottom (sill) of your casement window. Put together; they give a definite form to your window.

  • Head. As the name suggests, it is found in the topmost portion of the window. This horizontal bar runs across the uppermost part of the casement window.
  • Sill. This is the horizontal bar at the bottom of the window frame.
  • Jambs. These are the vertical bars on either side of your window frame.


This is the part of the window that can be opened outward. It is also where the glass panel is installed. Others refer to this as the sash.

  • Top Rail. It is the horizontal bar found at the top of the casement.
  • Bottom Rail. This is the horizontal bar placed at the bottom of the sash.
  • Stiles. The vertical edges on both sides of the casement are referred to as stiles.

Other Terms You Need To Know

  • Casing. This is the decorative molding around your window. It is placed between the wall and the window frame.
  • Fanlight. This is a small section under the head of the casement window that also opens. It is usually rectangular. You can think of it as a window within a window.
  • Mullion. This refers to the vertical bar that separates one casement from the other. It is connected to the window frame.
  • Transom. It is the horizontal bar that sets two casements apart. It is connected to the mullion.
  • Crank Operator. This is what you use to open and close the window. This was traditionally placed at the bottom of the frame. It has an arm or handles to make the operation smoother.
  • Aluminum Clad. This refers to the part of your window frame covered with aluminum. This is done to help protect the window from the elements and make it last longer.

There you go! You now understand the terms used to identify the different parts of a casement window. You can now discuss your window project without any confusion.

What Are The Different Types Of Casement Windows?

Colonial style casement window of white painted wood in a black tongue and groove plank facade, What Are The Different Parts Of A Casement Window?

Aside from the window parts, it's also good to familiarize yourself with the different types of casement windows. This will help you choose the right one for your window project.

There are three types of casement windows. Here they are:

Single Frame Casement Windows

This is the most basic type of casement window. As the name suggests, it only has one window frame. But it can have one or two casements.

Additionally, these windows can open inward or outward depending on how the window is mounted on the wall.

single casement window near light grey wall indoors

French Casement Windows

Typically, this type of casement window has two windows hinged on each side of the window frame, and they both meet at the center. These windows are reminiscent of French doors.

You can open them both outward for an unobstructed view of the outdoors or choose to swing out one casement giving you control of the ventilation.

Wooden windows and sill on a home exterior. Cottage windows

Push-Out Casement Windows

These are the least common casement windows and are pretty underrated. These windows are easy to open and enhance your security. The handle is easy to maneuver when you want to open your window.

Furthermore, it features a multi-point lock system that can be locked even when tilted. You can open this door inwardly or outwardly depending on the ventilation and air circulation you want.

Casement windows have three types - single frame, French, and push-out. Choose which one will suit your house best, not just in form but also in function.

Black frame aluminium windows of building

What Are The Pros And Cons Of Casement Windows?

There are different market window types, each with its own set of strengths and weaknesses. Here's what you can expect when you choose casement windows for your home.


Casement windows are easy to open. Just turn the crank to unlock it from its position and push it away from you.

They are recommended for those window openings in the hard-to-reach areas of your house, such as above the countertops and kitchen sink.

They open to the sides and from top to bottom, allowing more fresh air to enter your room. This also gives you a complete view of your outdoor area.

These windows are also more energy efficient than other window types that don't open all the way. As they allow more air to enter or circulate, your home is made cooler, reducing your cooling costs.

When closed, they form an airtight seal with the window frame so that no air can get in or out of the house. You can also add weather stripping along its perimeter to improve insulation.

Casement windows are also versatile. They can be made of different materials and come in various colors, so you can use them as part of a larger window installation. They'll work well with bay or bow windows.

These windows are also easy to clean on all sides. It's easy to reach all corners since they open all the way.


Generally, when casement windows are open, they protrude on the exterior portion of your house. They can cause accidents for people passing by who don't notice them.

They can also get damaged when there are heavy winds since they don't have much support other than the hinges on the side.

However, casement windows are also on the pricier side. Their frame and casement need to be made of stronger materials and have to use more hardware to support their weight.

You can't afford to choose low-quality materials as this would affect the performance and lifespan of your window. These windows also come in limited sizes. They can't be too wide since they swing outward.

You also need to be mindful of the maintenance of their hardware. They are prone to wear and tear and rusting since they are exposed to the elements.

Once the hardware deteriorates, the performance and amount of security will suffer.

You won't be able to install a window air conditioner on a casement window if you have plans to put one. You'll have too much open space, and it won't be able to provide adequate support to the AC unit.

These are the main benefits and drawbacks of using casement windows. Moreover, it's good to know these things so that you can assess if these windows fit your preference and need.

To Wrap It Up

Colonial style casement window of white painted wood in a black tongue and groove plank facade

You are now familiar with the anatomy of a casement window. You can use this knowledge when talking to your window dealer so that you won't be confused about the terms they use.

Hopefully, this will help you have a better grasp of what's the best window for your home.

Made it to the end? Check out these helpful related articles below:

Vinyl, Aluminum, Fiberglass, Or Composite Windows: Which Is Right For Your Home? 

Vinylmax Windows Vs. Pella Vs. Andersen: Which To Choose?

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