Transom Windows Installation

What is a Transom Window?

A transom window is usually distinguished from other window types by its location. Also known as “above door windows,” you will most often see them above a front door’s top frame or transom. Transom windows can also be installed above almost any exterior or interior door or window to bring in more natural light.

We can thank medieval builders for these windows. Transom windows were installed in European homes and other structures as early as the 14th century to brighten and ventilate homes while maintaining privacy and security. Today’s transom windows, also known as transom lights, are largely decorative. They can enhance a home’s architecture and add character.

While their height may vary depending on shape and style, transom windows commonly span the length of a door and its sidelights (the windows on each side of a front door) or an existing window.

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Types of Transom Windows

Transom windows are customarily organized by location first. Whether the transom window is installed on a home’s exterior or interior will often dictate the material, size, and shape.

Materials

Vinyl, wood, and aluminum are the most common framing materials. Transom window frames can also be made to match a home’s existing windows, both in material and color.

Sizes

Transom window widths typically match the dimension of the door or window beneath them. For example, a transom window will often traverse the width of a front door and sidelights if included. Transom window height will vary depending on its shape and a home’s ceiling height.

Shape

Common transom window shapes include arched, semi-arched, rectangular, and square. Fanlights are also a popular choice and consist of a semicircle opening with sash bars arranged in a fan-like look.

Fixed vs. Operable

Today, transom windows tend to be more decorative than functional, enhancing the home’s exterior appearance and architecture. Operational transom windows – or those that open and close – are also available and include the traditional crank opening and closure as well as remote operation.

Glass Type

There are a few different types of window glass you can choose from, as well. Due to their location above a door or window, clear glass is a popular choice, though tinted or frosted glass is also common. For a more decorative look, stained glass is also a lovely option if it complements your home’s architectural style. 

Benefits of Transom Windows

There has been a resurgence of interest in transom windows, from new home builds to home remodels. They offer several functional and decorative advantages that distinguish them from standard or other specialty windows.

• Increase Natural Light: Exterior transom windows harness more daylight by sitting above doors and windows. They help illuminate entryways and common rooms, even when blinds or curtains are drawn on the main window.
• Brighten Darker Rooms: Interior transom windows allow both natural and artificial light to pass between rooms, making hallways and interior spaces feel brighter without sacrificing privacy.
• Add to a Home’s Character: Transom windows can boost both exterior curb appeal and interior charm. Their classic shapes and decorative glass options enhance architectural detail.
• Create Privacy: Because of their high placement, transoms bring in light without compromising privacy, especially useful for entryways, bathrooms, or bedrooms.
• Improve Energy Efficiency: By increasing natural light and ventilation, transom windows reduce your reliance on artificial lighting and HVAC systems throughout the day.

Common Problems With Transom Windows

While transom windows offer charm and practical benefits, there are a few potential drawbacks to consider before installing them:

• Difficult Installation: Adding a transom window often requires modifying an existing wall or door frame, especially in older homes. If the window is being added to a load-bearing wall, structural reinforcement may be needed, which increases labor time and cost.
• Limited Privacy for Interior Models: Although you’ll usually see transom windows high up on a wall, interior transoms without tinted or frosted glass may still allow visibility between rooms, something to consider for bathrooms or bedrooms.
• Energy Efficiency Concerns: Depending on the type of glass, transom windows can affect your home’s insulation. Clear, single-pane transoms may not offer the same energy performance as double- or triple-pane windows, especially in extreme climates.
• Harder to Clean: Due to their high placement, transom windows can be harder to access for routine cleaning and maintenance, especially if you opt for a stained or decorative glass design that needs careful care.
• Cost Can Add Up: While a single transom window is relatively affordable, costs rise quickly with premium materials, specialty glass, or if structural work is required. Homeowners planning multiple installations should account for these additional expenses in their remodeling budget.

Transom Windows Design Ideas

A transom window is a great choice for any area of the home you would like to add more visual interest and a good source of natural light. As previously mentioned, this type of specialty window can be installed on a home’s exterior or interior. They work especially well in rooms that require some privacy, like bedrooms and bathrooms. Here are several common areas of the home where transom windows are installed:

• Exterior front doors
• As part of an exterior door kit that includes sidelights
• Exterior windows
• French doors
• Sliding glass doors
• Bi-fold glass doors
• Interior doors

Transom Window Structural Requirements

Transom window installation is commonly part of a home’s larger window remodeling project. It requires cutting away a section of the wall and removing the cladding, insulation, and framing to create an opening. For a load-bearing wall, the framing must be reinforced to maintain its structural integrity. Because of the additional construction work required, hiring a professional window installer is recommended for the best results. 

Another factor to keep in mind is your home’s ceiling height. Transom windows will require a ceiling height of at least eight feet to accommodate both the door and window.

How to Choose a Transom Window

To determine the shape and style of a transom window, let your home’s architecture be your guide. For example, an intricately patterned stained glass transom window is a hallmark of craftsman design, while a fanlight works best in Victorian, colonial revival, and southern architectural styles. For a more modern look, a rectangular or square transom window offers just the right amount of detail. Research your home’s particular style for ideas and inspiration, or contact a professional installer for recommendations. 

How Much Do Transom Windows Cost?

Transom windows are a low-cost window option, costing an average range of just $334 to $711 per window, with a national average of $459 per window. The window materials should cost about $249 to $531 per window, while professional installation will cost around $70 to $150 per window on average.

Transom Windows

Average Installation Cost $334 - $711

Cost Breakdown

• Materials 91.8%
• Labor 8.2%

A transom window is a relatively inexpensive window compared to the price of other window types. For instance, a single-hung window has an average cost of $397 to $847 and a double-hung window has an average cost of $429 to $915. Compared to other specialty windows like bay windows, garden windows, or picture windows, which can cost up to $3,700, a transom window looks like a real bargain.

Keep in mind this average cost for a transom window is a starting point. There are several factors that can quickly increase your total cost. For example, vinyl transom windows are the most budget-friendly option, while wood window frames can add approximately 50% more to the cost.

Features that Affect Transom Window Costs

Like any home improvement project, costs can vary slightly based on your needs. When installing a new transom window, some common factors that can make prices lower or rise include:

• Size of window
• Glazing
• Framing material
• Tinted or colored glass
• Stained glass
• Window grills
• Load-bearing wall construction

When purchased as part of an exterior door window kit that includes the door, frame, and sidelights, a transom window can run several thousand dollars.

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Finding the Best Window Professional

Most leading window manufacturers offer transom windows in various sizes, shapes, and materials. Our window comparison guide includes top brands and is a great start for your research and shopping. For expert advice and custom pricing, contact local window professionals to compare quotes. 

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