Transom windows are making a stylish return in 2025 home renovations, blending historical charm with modern functionality. Homeowners and designers are using these small yet impactful windows to maximize natural light, improve ventilation, and add architectural interest to contemporary homes. Whether enhancing open-concept spaces, lofts, or historic row houses, transom windows are proving to be both a design statement and a practical upgrade. Let’s learn about transom windows more!
Figure 1: Outdoor Transom Window
The History of Transom Windows
First off, let’s define the transom window. A transom window is a small window that sits above a door or window and is supported by a horizontal beam called a transom.
Transom windows have been a staple in architecture for centuries. Builders originally installed them above doors and windows to allow airflow and natural light before electricity became widespread. These windows were commonly found in Victorian, Colonial, and Craftsman-style homes, acting as both decorative and functional features. In the early 20th century, as central air conditioning and modern lighting took over, transom windows became less common.
However, the modern home design movement has sparked a renewed interest in light-maximizing, energy-efficient features, making transom windows a stylish and practical addition once again. Their ability to blend vintage charm with contemporary aesthetics positions them as a key trend in 2025 home renovations.
According to research by Grand View Research, the U.S. windows market was valued at $12.32 billion in 2022 and is projected to grow at a CAGR of 3.6% from 2023 to 2030, reflecting a growing demand for innovative window designs, including transom windows.
Why Transom Windows Could Trend in 2025
With homeowners and designers placing a greater emphasis on natural light, ventilation, and open-concept spaces, transom windows are re-emerging as a go-to feature in modern homes. Here’s why they are making a comeback:
1. Maximizing Natural Light
A transom window brightens interior spaces by allowing more sunlight to filter through, reducing the need for artificial lighting. This is particularly beneficial in compact urban homes, where windows are limited.
2. Enhancing Energy Efficiency
Incorporating a transom window can improve a home’s sustainability by lowering energy consumption. More natural light means less dependence on artificial lighting, and operable transoms allow for passive cooling, reducing HVAC usage.
3. Architectural Appeal & Customization
A transom window adds an elegant, customized touch to any space. Modern versions come in a variety of shapes and styles, from minimalist black-framed designs to ornate glass panels, making them suitable for any aesthetic.
4. Smart Home Integration
Innovations in smart glass technology allow transom windows to adjust tint levels based on sunlight exposure. Some even come with automated openers, enabling better airflow with a simple voice command or smartphone control.
Transom Window Dimensions
Choosing the right dimensions for transom windows depends on their intended function, location, and architectural style. Standard dimensions include:
- Width: Typically ranges between 24 to 72 inches, depending on the width of the door or window below.
- Height: Common heights range from 12 to 24 inches, though custom options can be taller.
- Frame Depth: Matches the depth of adjacent windows or doors, generally 4 to 6 inches.
- Custom Sizes: Available for unique architectural designs, allowing for narrow, elongated, or large-format transoms to suit modern homes.
When planning transom window installations, consider the proportions of the surrounding elements to ensure visual balance and functionality.
Where We’ll Likely See Transom Windows in 2025 Renovations
As home layouts continue evolving, transom windows are being used in more creative ways beyond their traditional placement. Here’s where they’ll make the biggest impact:
- Above interior doors: Keeping rooms visually connected while allowing light to flow between spaces in open-concept designs. Ideal for hallways, home offices, and bedrooms.
Figure2: Transom Windows above Interior Doors
- Over large sliding or French doors: Enhancing indoor-outdoor integration in modern homes by extending glass coverage, creating a seamless transition between interior and exterior spaces.
Figure 3: Transom Windows above French Doors
- In modern lofts, ADUs, and home offices: Transoms are ideal for maximizing light and airflow in compact spaces like accessory dwelling units (ADUs) and urban lofts, where privacy is still essential.
- Smart transoms in high-tech renovations: Automated transom windows with ventilation sensors help regulate indoor temperatures, reducing reliance on traditional heating and cooling systems.
According to a report by Freedonia Group, global demand for windows and doors is forecast to increase by 2.8% per year, reaching $308 billion in 2028, further supporting the resurgence of transom windows in modern renovations.
Transom Windows in Philly Row Houses
Philadelphia’s historic row houses often have deep, narrow interiors with limited windows, making natural light a challenge. Traditionally, these homes utilized transom windows above doors to improve ventilation before modern HVAC systems were common.
In 2025, transom windows are finding new life in Philadelphia renovations, particularly in:
- Narrow row homes where extra light is needed in windowless hallways and stairwells.
- Multi-family conversions, where maintaining separate yet airy units is essential.
- Renovated brownstones blending old-world charm with modern conveniences.
Figure 4: Transom Window in a Philadelphia Row House
Don’t Confuse Transom Windows with Clerestory Windows
Though they serve similar purposes, transom windows and clerestory windows are not the same:
- A transom window is installed above doors or other windows, typically for added light and airflow.
- Clerestory windows are positioned higher up on walls, often near the ceiling, designed to bring in continuous natural light while maintaining privacy.
Both types add brightness to a space, but a transom window tends to be smaller and more architectural, while a clerestory window creates dramatic light effects in open-concept homes.
Figure 5: Transom Windows Vs. Clerestory Windows
How Transom Windows Help Increase Natural Light
These windows play a significant role in enhancing natural light distribution throughout a home. They allow sunlight to penetrate deeper into interiors, making rooms feel brighter and more open. By placing transom windows strategically, homeowners can create a more airy and spacious atmosphere while reducing reliance on artificial lighting. Below are some key areas where transom windows make a noticeable difference:
1. Kitchen
Placing a transom window above a doorway or over upper kitchen cabinets allows more daylight to penetrate the cooking space, making it feel larger and more inviting. It also creates an open, welcoming ambiance, especially in compact kitchens.
Figure 6: Transom Windows in a Kitchen
2. Hallway
Hallways, especially in older homes, tend to be dark due to limited windows. A transom window between rooms or over a door helps distribute light from adjoining spaces, creating a brighter and more connected feel.
Figure 7: Transom Windows in a Hallway
3. Living Room & Dining Areas
For homes with vaulted ceilings, a transom window creates an elegant design feature while allowing sunlight to flood common areas. They can be paired with floor-to-ceiling windows or French doors to maximize brightness.
Figure 8: Transom Windows in a Living Room
4. Bathrooms
Adding transom windows in bathrooms brings in natural light without compromising privacy. Frosted or etched glass options keep spaces bright while maintaining discretion. This is especially useful in homes where standard windows may not be an option due to space limitations.
Figure 9: Transom Windows in a Bathroom
5. Bedrooms
To balance light and privacy, a transom window between the bedroom and adjacent hallway can allow for soft, ambient lighting throughout the day. It helps make small bedrooms feel larger and more breathable without the need for oversized windows.
Figure 10: Transom Windows in a Bedroom
According to modernize.com, the average cost of transom windows ranges from $334 to $711 per window, with a national average of $459 per window, making them a cost-effective upgrade for increasing natural light.
Structural Considerations for Installing a Transom Window
Installing a transom window requires structural modifications, especially in load-bearing walls. The process begins with removing drywall and/or exterior cladding above the door to expose the framing. If the wall is non-load-bearing, a simple reframing may suffice. However, for load-bearing walls, removing studs necessitates adding a structural header beam to redistribute weight and maintain the wall’s integrity. Additional cripple studs and sill plates are installed to properly frame and support the transom window. Ensuring the rough opening is level and secure before installing the window is critical to avoid misalignment and long-term structural issues.
Once the transom window is in place, the surrounding area must be reinforced and sealed. New drywall or exterior cladding is installed, and for exterior applications, proper flashing and insulation are added to prevent air and moisture infiltration. If the window is operable, hinges or latches must be securely attached to avoid unnecessary strain on the frame. The final steps involve sealing all gaps with caulk and finishing with appropriate trim to restore the wall’s aesthetic and structural continuity. Proper execution ensures the transom window not only enhances natural light and ventilation but also integrates safely into the home’s structure.
The above explanation was general installation considerations, but if you are interested in a Step-by-Step Transom Installation Guide, let us know in the comments below.
Philadelphia Code Requirements for Transom Windows
When planning to add or replace a transom window in Philadelphia, it’s essential to adhere to the city’s building codes and regulations to ensure safety and compliance. Here’s a comprehensive guide to the requirements:
1. Applicable Building Codes
The city follows the 2018 International Building Code (IBC) with local amendments. Any structural modifications, including the installation of a transom window, must comply with these standards.
For one- and two-family dwellings, the city adheres to the 2018 International Residential Code (IRC) with specific local amendments. Ensure that transom window installations in residential properties meet these requirements.
2. Permit Requirements
Philadelphia offers an EZ Permit process for the replacement of exterior windows and doors without the need for detailed plans, provided specific conditions and design limitations are met. This streamlined process is detailed in the city’s EZ Permit Standards. So, if you want to replace an existing transom window you will probably be able to do it with an EZ Permit
If your project involves structural changes, such as enlarging openings or adding new transom windows where none previously existed, a standard building permit is required. This process necessitates the submission of detailed plans and adherence to all applicable building codes.
3. Safety Glazing Requirements
According to the 2018 IBC and IRC, certain windows, especially those in hazardous locations, must use safety glazing materials like tempered or laminated glass. Transom windows are typically positioned above doors or other windows. Therefore, they don’t fall into categories requiring safety glazing. However, make sure to consult professionals for your project.
For more information regarding safety glass requirements in Philadelphia refer to this article: Safety Window Glass for Your Philadelphia Home: A Complete Guide
4. Historic Preservation Considerations
If your building is designated as historic or is located within a historic district, additional approvals may be necessary for modifications like adding or altering transom windows. The Philadelphia Historical Commission oversees such matters and should be consulted to ensure compliance with preservation standards.
Conclusion
With home design trends shifting toward light-filled, energy-efficient, and architecturally distinct spaces, transom windows are poised to make a big comeback in 2025. Whether in urban row homes, loft apartments, or high-tech renovations, they add both style and functionality to modern living.
By enhancing natural light, ventilation, and home aesthetics, transom windows are proving that a classic architectural feature can still thrive in the future of home design. If you’re considering a home renovation, incorporating transom windows might just be the perfect way to bring in brightness and beauty while embracing a timeless trend.
Looking to add transom windows to your next renovation project? Contact us Today. We are here to help you with all your home renovation needs in Philadelphia and South Jersey!
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