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What Are Transom Windows? (2024 Guide)

Learn about transom window styles, cost, and function in our guide.

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Author Image Written by Jessica Wimmer Updated 04/09/2024

Transom windows sit over a door or other window on top of a horizontal beam, called a transom. They can be decorative or functional and have been popular since the 14th century. We’ll explore what transom windows are and whether you want to install them in a new home or revive historical flair in a renovated older one. 

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What Is a Transom Window?

Transom windows are rectangular or semicircular windows installed on top of a door or other window. You’ll notice them in many older homes. They come in various shapes and materials and are an interesting way to add character and express your personal style. They can be over front doors, exterior windows, or interior doors. Most transom windows are now decorative, but they once served a valuable purpose.

New Windows in Home
Window Replacement

Window replacement typically costs $300–$2,000 per window, depending on the window type.

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Window Repair

Window repair typically costs $177–$623, but it can vary based on the type of repair.

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Window Cleaning Cost

Window cleaning typically costs $80–$430 for an entire home.


What’s the Purpose of a Transom Window?

Before homes had electricity and air conditioning, transom windows added natural light and airflow. They sit above the eyeline, helping homeowners maintain privacy. Original transom windows were made to open from the bottom up using metal hinges. Exterior transom windows let in air from outside, while interior transom windows help circulate air throughout the home. Modern transom windows are primarily decorative and typically don’t open.

Types of Transom Windows

Transom windows offer diverse shapes, colors, sizes, and materials that can match any design aesthetic. 

Rectangular and semicircular are the most common shapes. These range from a few inches high to a few feet if you have the ceiling height. Single or multipaned rectangular transom windows are typically installed over doors and extend the length of the doorframe. Transom windows on exterior doors with side windows, called sidelights, extend the width of the full unit. Semicircular transom windows, also called fanlights, are often installed above both doors and windows. They can be single, multipaned, and even domed to look like an awning.


You can choose from stained, textured, frosted, clear glass, wood, vinyl, aluminum, or fiberglass window frames. You can also opt for operable or inoperable transom windows. Many of the best window brands still make operable transom windows. Some higher-cost varieties even include a moisture sensor that automatically closes the window when it rains.

Installing a Transom Window

A licensed contractor can install a transom window in both new construction and existing homes. They’re easiest to install during construction, but most licensed contractors have experience putting them in older homes.

If you want just a transom window, a contractor will cut a hole above your existing door or window, position the unit, and then put new drywall around it, requiring fresh paint. The contractor will need to remove and replace exterior cladding as well.

If you’re adding a transom window to an exterior door or window, it’s recommended that you install a new door or window system that includes the door, transom window, and any sidelights in one sealed unit. This will prevent issues with moisture, pests, and energy efficiency.

Transom Window Cost

Transom window costs vary by size and style. Simple, inoperable transom windows with clear glass and wood, vinyl, or aluminum framing typically start around $100. Larger and more elaborate transom windows, such as those with stained or designed glass, domed glass, or the ability to open, can cost several hundred dollars. Full systems that include a door, transom window, and side windows can cost thousands.

See our guide to window replacement costs for more information.

What To Know About Transom Windows

Consider a few things before installing transom windows. First, ensure the wall is structurally sound. Then, ensure you have tall enough ceilings to install a transom window without it looking out of place. If you’ve found a transom window you like, read the product specifications to determine how much framing space is required for that model and whether your existing door or window will pair with it. 

You may also want to budget for window replacement to match your existing window to the new transom window.

Our Conclusion

Transom windows add historic charm and architectural intrigue. Most builders stopped installing them in new homes during the early 2000s, but they’re a relatively easy way to bring character to a new home or revitalize a renovated historic home.

We recommend hiring a licensed contractor to install the transom window. Doing it yourself can cause structural, pest, or energy efficiency problems. If you’re building a home, hire a designer and work with qualified craftsmen to ensure your transom window is installed correctly.

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FAQ About Transom Windows

What is the purpose of a transom window?

The primary purpose of a transom window is decoration. However, these windows also allow more natural light into a room and can increase airflow if the window opens.

What is considered a transom window?

Transom windows are any windows that sit on top of a transom, which is the beam over a door or other window. 

Can transom windows be opened?

Though many transom windows are inoperable, some variations open via metal hinges from the bottom up.

Are transom windows outdated?

Transom windows have fluctuated in popularity over the years. Though some may consider them outdated, many homeowners revive them to add character and an interesting architectural style. Modern transom windows often feature designs that complement today’s trends.

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