A transom is a horizontal beam or crosspiece above a door or window that separates it from the exterior wall. Above the beam is the transom window, or "transom light", which is designed to create cross ventilation and/or bring in additional light to your home while the door is closed.
Like Jalousie windows, exterior transom windows have been used for hundreds of years and served as a precursor to air conditioning but modern transom windows are now primarily used for decorative purposes. Transom windows are a great option for bringing in more light to an entry room, dining room, or kitchen – especially if you have French doors. Let's take a look at how transom windows work and determine if they're worth buying for your home.
How do transom windows work?
Image source: TLC Builders
In the 1800s, transom windows were used for increasing airflow and bringing in more natural light while also featuring decorative design elements like stained glass and sophisticated shapes. Operable transom windows feature sashes located on the sides, bottom, or top of the window that allows it to open as much or as little as you want.
Transom windows are often confused for mullions, but here's the difference. While transoms are horizontal beams above windows and interior doors or exterior doors, mullions are vertical beams that separate smaller windows and offer structural support to the window arch.
Transom window styles
Fanned window
Image source: The Rhythm of the House
The more traditional type of transom window is a fanned-out window, sometimes referred to as fanlights. Sometimes, fanned transom windows on the front door will have other windows on the sides called sidelights. But these types of arched transom windows are mostly for appearances only and don't typically open for ventilation.
Paneled glass
Image source: Laurel Home
Paneled glass transom windows feature a frame that is designed to create a grid-like appearance. These windows typically feature window hardware like hinges or a metal rod system and are separated by vertical strip dividers which gives them a more symmetrical appearance.
Solid window
Image source: Window Film World
Solid windows are similar to multi-paneled transoms but feature a single piece of glass in a solid frame. The windows sometimes feature intricate architectural details like frosted, colored, or etched glass. Solid windows can also be hinged on the frame, allowing for ventilation.
Pros and cons of transom windows
Image source: Realtor.com
Pros of transom windows
More sunlight - While transom windows initially were designed to bring in fresh air before air conditioning was invented and more readily available, transom windows also bring in a great deal of sunlight. No matter which direction your home is facing, transom windows are a great option for lighting up the darkest of rooms and entryways.
Environmentally friendly - Because most transom windows are fixed and don't open, they keep all of the cool air in your home and you won't have to worry about any type of leakage.
Aesthetically pleasing - Today, transom windows are primarily used for decorative purposes, and can even increase the curb appeal of your home. Other architectural elements like stained glass are also popular designs among homeowners and can increase your property value.
Cons of transom windows
More heat - Because most transom windows these days are fixed and they bring in more sunlight, they also bring in more heat, which could increase your cooling costs.
Hard to clean - Since most transom windows are above entry door frames or windows, they can be hard to reach and difficult to clean both inside and outside.
Better options - While transom windows do have their benefits, there are noticeable drawbacks, such as ventilation. If you're looking for windows that increase airflow or bring in more sunlight, casement windows, awning windows, or any single or double hung window is a more modern option.
Are transom windows worth it?
While they may be aesthetically pleasing and can bring in more sunlight, exterior and interior transom windows are primarily used these days for decoration. Like jalousie windows, transom windows are a thing of the past and were used as a precursor to air conditioning to increase airflow. New transom windows are decorative and can offer some type of value, but there are better options available like casements, double-hung, and slider windows.
Chris Gennone is a content specialist and video producer at Fixr.com. He has 5 years of experience writing and editing for a variety of web and print publications, currently specializing in home improvement projects such as roofing, remodeling, and repairs. When Chris isn’t writing or in front of the camera, he’s either playing with his band or tracking down the best sandwich shops.