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What Are Transom Windows? (2023 Guide)

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

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You’ve likely seen a transom window, though you may not have known what it’s called. Transom windows sit over a door or other window on top of a horizontal beam, called a transom. They can be either decorative or functional and have been popular since the 14th century. Whether you want to install transom windows in a new home or revive historical flair in a renovated older one, here’s what to know. 

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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. Transom windows 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 and exterior windows or over interior doors. Most transom windows are now decorative, but they once served a valuable purpose.

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Window Replacement

Window replacement typically costs $234–$1,224 per window, depending on the window type.

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Window Repair

Window repair typically costs $100–$600, but it can vary based on the type of repair.

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Window Cleaning Cost

Window cleaning typically costs $150–$300 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 eye line, helping homeowners to 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 helped to circulate air throughout the home. Now, transom windows are primarily decorative only.

Types of Transom Windows

Transom windows come in multiple sizes, shapes, colors, and materials. 

The most common shapes are rectangular and semicircular. These can be just a few inches high or as much as 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, or clear glass and 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 also have experience putting them in older homes. 

If you want just a transom window by itself, a contractor will cut a hole above your existing door or window, position the unit, then put new drywall around it, requiring fresh paint. Exterior cladding will also need to be removed and replaced. 

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

The cost of transom windows varies 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

There are a few things to consider before installing transom windows. Firstly, you’ll need to ensure the wall you want to install the window on is structurally sound. You’ll also need to make sure 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 if 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 historic home that’s been renovated.

We recommend hiring a licensed contractor for transom window installation. Doing it yourself could cause structural, pest, or energy efficiency problems. Hire a designer if you’re building a home 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 is designed to open. 

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 are reviving them as a way to add character and interesting architectural style. Modern transom windows often feature designs complementary to today’s design trends. 

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