What Are Transom Windows, Anyway?

published Oct 8, 2022
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Ever see those small panes of glass above doorways and wonder what they’re called? Those little guys are known as transom windows.

Transom windows were originally used as a way to allow more air flow into a home or building without compromising security and privacy. Because they’re placed above a door or window, their height means that prying eyes can’t see through, but when open, air can move throughout a space. They also allow more natural light into a home and because of their height, don’t necessarily need window coverings. While they date back to the 14th century, they enjoyed popularity in the 18th century in Georgian-style abodes.

Current versions of transom windows are mostly decorative and rarely open. But older houses may retain the traditional style that opens with a rod and hinge system. In fact, the house I grew up in was built in 1906 and has an operable transom window above the front door. 

What is considered a transom window?

A transom window is named for its location above the transom — the upper beam — of a door or window. Because of this, there really isn’t a standard size or style that is considered a transom window. 

The length of a transom window is determined by the length of the transom, so the transom window will be as wide as the doorframe or window. Beyond that, transom windows can be a rectangle or a semi circle. They can have muntins — the pieces of wood that separate panes of glass — be stained glass, or have one solid pane among other designs.

Interior doors can also include transom windows, which were originally meant to help air flow throughout a home. These days, they can be used as a design element and to help the space feel more open and connected.

Credit: Bentley Davis/Shutterstock.com

What is a transom window used for?

Today’s transom windows are mostly used as a way to increase the natural light in a home. Their original purpose of allowing air flow into and around the interior of a home has largely been replaced with central air conditioning, so few modern transom windows are operable. They also add an interesting design element.

Are transom windows expensive?

Transom windows are considered a relatively inexpensive addition to a window or door system. They cost between $140 and $300 for materials and installation, according to Modernize Home Services. While they typically don’t open to allow air flow, they do welcome natural light and can add to your home’s resale value.

What is the difference between a transom window and a clerestory window?

Clerestory windows differ from transom windows in that they are located high on a wall, just below the roof line. This style of window is intended to allow more ambient light into a space and expand available views, like in this home whose owners enjoy their views of the tops of nearby palm trees. As with transom windows, clerestory windows are named for their location, and as a result their form can differ — some are incredibly wide while others are narrow, and they can also come in different shapes.