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What is a Transom Window?

A wooden front door with transom windows.
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Transom Windows

You’ve probably seen transom windows on houses more times than you can count, but you might not know what they are, how to define them or what purpose they serve.

What Is a Transom Window?

Transom windows are named as such because they are located over top of a window or door’s transom– this is the beam that separates the top of the window or door from the rest of the wall.

Consequently, transom windows can come in many different shapes, styles and designs, but retain the name due to their location. The only general difference in transom windows installed above doors and those installed above windows is the size—they generally match the width of the transom.

transom window glass

What is the Purpose of a Transom Window?

The purpose of a transom window dates back to the days when air conditioning had not yet been invented. Back then, transom windows were opened and closed to allow ventilation from the outside to inside, and from room to room within homes or businesses—yes, transom windows can be installed on interior walls as well as exterior walls.

Because transom windows are usually high in the air, they allowed for a door or window underneath to stay shut, retaining privacy and security. The windows were operated with metal rods on hinges that allowed them to be opened and closed from ground level.

Today, it is rare to see a transom window that opens at all, and even rarer to see the rod systems used to open and close them. Typically these windows are now used for letting in more light, especially in morning or evening hours. Or they are simply a decorative design element. If they do open or close, this is usually operated by an electronic switch.

Transom Window Styles

Transom windows come in a variety of styles. The most traditional and widely recognized transom window style is a semicircular window with dividers separating the panes in equal radius. This style of transom window is sometimes referred to as a fanlite. The second most popular style is a simple rectangular shape. Windows can even be custom-made to fit certain spaces. This can be especially important if the ceiling above is angled.

The options available for frame color and material and glass type are as endless as they are for doors and other types of windows. Frame materials come in the form of wood, vinyl, aluminum, fiberglass and more which can be chosen to match other design elements of the home. Some homeowners opt to use clear glass, while others opt for textured or frosted glass.

home with transom windows

Installing Transom Windows

The easiest installation method is during the design phase of new construction when it is possible to ensure that openings and support beams allow for a transom window to be installed.

However, transom windows can be added to existing homes as well. It will take some work by a licensed contractor to modify the area above the door and window in order to install the transom window. They will have to cut out an opening where it will be installed, which can be a scary prospect for some homeowners.

When looking at transom window options, you may opt for a matching door and frameset that can include a pre-mounted transom window. This will help ensure that everything fits together properly and all the finishes will match. It makes for an easy installation and is a great way to add an overall facelift to the front entrance of your home.

If you’re looking to install or replace just the transom window itself, this is possible too. There are options ranging from simple, plain windows, to completely custom designs and shapes. The price will vary accordingly. Installation costs will depend on the size and what modifications are needed in order to complete the installation.

Transom Window on a door

Is Your Home Ready for an Upgrade?

If you’re ready to have a new transom window installed in your home, use to find local, reputable dealers in your area and obtain no-obligation price quotes. Our affiliates will guide you through the process of choosing the best transom window option for your budget and your home’s style. Many of our dealers will come to you for in-home consultations and some even have showrooms where you can see different options in person.

Not ready to take that next leap yet and still doing research on your future renovation projects? Check out our other blogs that can help you make educated decisions when investing in new doors or windows for your home.

Please note, this article may contain links to Amazon products. As an Amazon Associate, earns from qualifying purchases.



Daniel Snow

Daniel Snow serves as the Vice President of Operations for and is also a contributing editor. He earned a Bachelor’s Degree in Business Management from George Mason University and has a background in the real estate industry. After high school, Daniel even worked at a family-owned glass shop for a short period of time and is an Auto Glass Safety Council certified installer. In his free time, Daniel enjoys being outdoors, especially around the water where he can be found surfing, fishing, and boating. He has a passion for bringing old vehicles back to life and loves working with his hands to restore cars, boats, and motorcycles. Find out more about Daniel on Linkedin.

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8 Responses

    1. Hi Pam,

      There are a few options- you could use custom blinds or curtains, or window film. All would do the job adequately.

  1. Thanks for helping me understand that the cost for the installation of this window will depend on the size and modifications needed. This is a piece of really helpful information because it will help me prepare for the replacement financially. We just need this to be done now that we noticed how damaged the windows are such as having gaps already. It might be due to the house being over five decades old when we bought it.

  2. In my 1970’s built ground floor flat there are these transom pieces of glass above 3 rooms in my home, can you please tell me what is their purpose?

    1. Hi Linda,
      Thanks for the question! This can really only be accurately answered by the original architect. Sometimes transom windows are strictly aesthetic. Other times they allow in additional light. If they’re operable (open and close on hinges), they are very functional- letting air to flow in and out of a room while still allowing the door to be kept closed for privacy and security.

  3. I am looking for an exterior door ( 36”X80) full clear glass with a sidelight on both sides (15”X80) and a transom approx 72X 12” . I am replacing a 72” wide French door & would like it to fit as close as possible. 4.625 jam width. Fiberglass for I live on the beach with high salt exposure- metal doors deteriorate in 3 or 4 years and wooded doors require semi-annual maintenance.Can you help?

  4. I see on your site that a transom window is above the front door of a home, but what is it called if the front door of a home has an artistic stained glass or clear window in the upper 4th of the front door itself instead of above it? Are customers able to request their own custom designed window in a front door like I described?

    1. Andrew, thanks for commenting with your question. A door that contains a piece of glass is typically referred to as a “lited door”. In your case, if you search “quarter lighted door” you should find the results you’re looking for.

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