Key Takeaways
- Dormer windows provide natural light, more headspace, and airflow to upper floors.
- The gable is a common type of dormer window, which pairs well with Colonial homes.
- Installing a new dormer costs $12,000–$30,000 on average.
A dormer, or dormer window, projects vertically from a roof to provide additional natural light and headroom to upper-floor spaces, including attics and lofts. They add unique character to a home’s exterior, especially on traditional or historic buildings. There are several types of dormer windows available, such as gable, shed, hipped, and eyebrow.
The right dormer window for your home depends on its architecture, as well as your budget and goals. Kent Buell, owner of Kentstruction in Medford, New York, explained that gable dormers are among the most popular. “A lot of the homes we work on are Cape Cod houses. We take the roof off, add makeshift walls, and create a whole new roof line.”
Since constructing a brand-new dormer is an extensive project, it typically averages between $12,000 and $30,000. The exact cost depends on the dormer’s size, materials, style, and other variables. Dormer window replacement is more affordable — often $200 to $1,300 — but you could pay more for custom designs.
Installing a new dormer requires careful planning, as the chosen style must match your home’s architecture while adhering to the building’s structural limitations. In this article, we highlight the most common types of dormer windows, break down costs, and explain how to select the right design for your home.
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Costs in this article are sourced from RSMeans, a price estimator database for contractors, and contractor estimates used by Angi.
What Is a Dormer?
A dormer, also known as a dormer window, is a small extension built into the roof. It projects vertically, with its own roofed structure. Dormers can bring in natural light, ventilation, and additional space, though the benefits depend on the type of dormer and window you choose.
There are multiple dormer styles, though a gable is the most popular. Buell also mentioned reverse dormers, which pair well with terraces and balconies. “Partial dormers are common, too, particularly in master bedrooms and bathrooms,” he added.
“Dormers don’t usually need repairs. They can last 80 to 100 years or more. For the windows, you may need to replace the glass in the sash or replace the sash,” Buell said. The lifespan of your dormer depends on the construction material and installation quality.
Types of Dormer Windows
Your home’s architectural style usually dictates the best type of dormer window for you. Here’s a look at some of the common types, along with details about their frames and ideal window styles.
Gable Dormer Window
A classic and simple design, the gable style is one of the most common types of dormers, often seen on Colonial, Cape Cod, and traditional homes. Also known as a doghouse dormer, it has vertical walls and a pitched, triangular roof with two sloping, symmetrical sides. The two sides meet at the top, mimicking the main roof’s form and pitch.
You’ll usually find single-hung, double-hung, or casement windows in gable dormers, but experts also recommend awning and specialty windows. Some homeowners with traditional homes choose arched windows for elegance.
Shed Dormer Window
Ideal for bungalows, Craftsman-style houses, and Colonial homes — as well as attic renovations — shed dormers feature a single-sloped roof from the main roof, but usually with a lower pitch. Homeowners may add several smaller shed dormers, but many opt for an addition that stretches the length of the room or house.
Longer dormers increase the room’s size significantly, while also creating more wall space for multiple or larger windows, adding more natural light and airflow. Typically, homeowners install three to five casement, awning, or picture windows.
Hip Dormer Window
Hip, or hipped, dormers have three roof sides that slope down toward the walls. While they’re more complex to construct than other types of roof dormers, their finished design is elegant and compact. They can also provide more ventilation compared to other styles.
Hip roof dormers are best for cottages, Prairie-style, and ranch homes, as well as those with intricate rooflines or limited vertical space. Choose a classic window for this type of dormer, such as a casement or double-hung window.
Eyebrow Dormer Window
Eyebrow dormers, also known as roof eyebrows, have distinctive curved tops, similar to their namesake. The low profile gently rises, with either end of the dormer’s roof blending into the main roof. Eyebrow dormers tend to be smaller, with a greater focus on decoration rather than functionality, but they can still create a cozy interior space.
Due to the design, we recommend going with a small, curved window. Roof eyebrows look best on historic homes, European-style architecture, custom builds, and cottages.
Wall Dormer Window
Wall dormers extend from the home’s wall, rather than the roof, which adds even more space to a room compared to roof dormers. They project upward past the main roof, and you can choose which style of roof you’d like, such as gable, hipped, or arched.
Since wall dormers are versatile, they pair well with a variety of home designs, from Gothic Revival to farmhouse style. Some homeowners use these dormers to access balconies or rooftop terraces. To make the most of your wall dormer, consider using casement, picture, or French-style windows.
Arched Dormer Window
With a smooth, rounded roof, arched dormers add character and a classical design to homes, visually softening sharp rooflines. They’re also called arched top, segmental, or bonner dormers.
Due to the design of arched dormers, you’re limited in window options and shapes. We recommend choosing an arched window that matches the dormer’s curve. Arched dormers aren’t as popular as other types, but you’ll frequently find them on French-style, Mediterranean, Victorian, and luxury homes.
Reversed Dormer Window
Also known as an inverted or negative dormer, a reversed dormer cuts into the roof plane to form a recessed alcove. You may choose this design if you want to add outdoor space, such as a terrace or balcony, or to extend the top floor’s headroom without increasing the main roof’s size.
Reversed dormers are complex and require careful planning, especially for drainage. Picture windows are an excellent choice, but consider using sliding or French doors if you plan to use the space as a balcony. The inverted design is best suited for modern architecture, minimalist homes, and green roofs.
Window Styles Commonly Used in Dormers
You’ll often find dormers paired with casement, double-hung, fixed, and awning windows. Here’s a quick overview of popular types of windows for various dormer styles:
| Dormer Style | Best Window Styles |
|---|---|
| Gable | Casement Double-hung Single-hung |
| Shed | Awning Casement Picture |
| Hip | Casement Double-hung |
| Eyebrow | Custom-curved Fixed Half-moon |
| Wall | Casement Double-hung French-style Picture |
| Arched | Arch-top Segmental-arched |
| Reversed | French doors Picture Sliding doors |
Roof Dormer Cost Considerations
On average, it costs $12,000–$30,000 to install a new roof dormer, or $120 per square foot, with labor making up 50% of the total bill.
The exact cost depends on several factors, including:
- Dormer structure: Complex, hip, and gable dormers cost more than other styles, often ranging between $110 and $150 per square foot. Shed dormers are on the lower end, averaging $80 to $120 per square foot. You can save by opting for a prefabricated style, which costs $70 to $100 per square foot.
- Dormer size: The larger the dormer, the more you’ll pay. A small 25-square-foot dormer averages between $2,500 and $6,300, while a 250-square-foot structure can cost up to $50,000.
- Roof material: Common roof materials include asphalt, clay, wood, slate, and metal. Asphalt is an affordable option at $4–$10 per square foot. Metal is on the higher end, ranging from $8 to $22 per square foot.
- Window: Window prices depend on factors such as size, type, installation complexity, material, and energy efficiency. Popular options range from $200 to $1,300, but you could pay more for custom designs.
- Additional expenses: You’ll pay extra if your roof needs repairs or if the contractor has to reinforce the home’s foundation to support the dormer’s additional weight. Your project may also require permits, cladding, and drainage.
However, if you’re simply replacing an existing dormer window and not constructing a new dormer, it’s much more affordable. Window replacement costs average $400–$1,000 per window, but you’ll pay more if it’s difficult to access the dormer or if you need a larger, custom, or energy-efficient design.
This table breaks down common dormer windows and their related costs.
| Dormer Window Type | Average Cost per Window |
|---|---|
| Single-hung | $200–$400 |
| Awning | $430–$830 |
| Double-hung | $430–$915 |
| Arched | $350–$1,000 |
| Casement | $500–$1,000 |
| Picture | $700–$1,300 |
| Custom | $1,000+ |
How To Choose the Right Dormer Window
Whether you’re installing a brand new dormer or replacing the window, here are some things you should keep in mind and questions you should ask yourself to choose the best window for your home:
- Design goals: Your dormer and dormer windows should complement your home’s architecture to enhance its curb appeal and create a seamless design. For example, a picture window pairs well with a shed dormer, but it doesn’t fit the style of a roof eyebrow.
- Function: Do you need your windows to provide natural light or a view? If so, you may want to opt for a larger design. If you require additional ventilation in the space, select an operable window rather than a fixed-style window.
- Structural limitations: Each home and roof has a load-bearing capacity. If you add a larger dormer, will your home’s structure be able to support the added weight? You might need to work with a structural engineer to determine whether your current foundation and roof meet your needs.
- Building codes: Some regions have restrictions on dormers, windows, and sizes — or require (and charge for) related permits.
- Energy efficiency: Opt for a double-hung window over a single-hung for added energy efficiency. Low-emissivity (low-e) glass also prevents heat loss, but you’ll pay more.
- Budget: Larger or custom-designed windows and dormers can cost thousands of dollars more than prefabricated styles.
Next Steps
A roof dormer window can increase a room’s size, improve the home’s curb appeal, and allow more airflow and natural light into a space. If you’re considering installing a new dormer, work with a professional contractor to choose the best design and window styles for your architecture. They can provide advice on how to move forward with your vision, interior design goals, and budget.
FAQs About Dormer Windows
What is the most popular dormer type?
Gabled dormers are the most common type of dormers. They fit a variety of architectural styles, from Colonial to traditional, as their roofs match the design and pitch of the home’s main roof. You’ll find gables most often on steep-pitched roofs, where they add additional space to the top floor.
Single-hung, double-hung, and casement windows are ideal for gable dormers. Some traditional homes also pair well with arched window designs.
However, gable dormer installations tend to be more expensive than other styles. You’ll pay between $110 and $150 per square foot on average. Common gable dormer window replacements range from $200 to $1,000, depending on the window type.
Can I add a dormer to an existing home?
Yes, you can generally add a dormer to an existing home. However, factors such as costs and the house’s load-bearing capacity could limit your options.
Adding a dormer to an existing home tends to cost between $12,000 and $30,000. The dormer’s style, size, material, and window all impact the total price. You’ll pay much more for a larger dormer with a metal roof than you would for a smaller dormer with an asphalt roof.
In addition, all homes have a load-bearing capacity. If your current structure can’t handle the additional weight of a dormer, reinforcing the building’s foundation could allow you to tackle this home improvement project. You may also be limited to certain dormer styles and sizes depending on your home’s design.
Are dormer windows energy-efficient?
Yes, dormers are energy-efficient, as long as they are designed and installed correctly. The added natural light reduces the need for artificial lighting and electricity during the day, and operable windows can provide cross-ventilation.
Buell explained that dormers are highly energy-efficient because heat rises, second stories have more insulation than first floors, and insulation has come a long way in recent years. However, he added, “You’ll also have more space to heat.” Without a plan, the addition could increase your energy bills.
Make your dormers even more energy-efficient by selecting the right insulation for your climate and home and by purchasing energy-efficient windows with low-e glass.
What are common signs you need to repair a roof dormer?
Common signs your roof dormer needs repair include visible wear and tear, peeling paint, mold, mildew, dripping water, odd odors, discoloration on the ceiling, rot, or warping. Many of these signs indicate water damage, which can lead to health issues and higher energy bills.
In most cases, your dormer shouldn’t need repair as long as it’s within the lifespan of the construction materials. Well-constructed dormers can last 80 to 100 years or more, according to Buell. However, if you choose less expensive materials, such as asphalt, you’ll likely have to replace the shingles within 30 years.
Help extend the lifespan of your dormer by checking it regularly for leaks, poor ventilation, and damaged shingles or tiles. Clean your gutters at least twice a year to minimize the risk of drainage issues and water damage.
What is the difference between a dormer window and a skylight?
A dormer window is a vertical window built into a small structure on the roof or wall of a home. Most dormers increase the interior space, but adding a new dormer often costs between $12,000 and $30,000. The window can be fixed or operable. On average, replacement dormer windows range from $200 to $1,300 or more for custom pieces.
A skylight is a flat window against the roof. As with dormer windows, it may be operable or fixed, but it’s not usually easy to reach. Many operable skylights require telescoping poles, which you can use to open and close the window. Replacement skylights tend to cost between $1,000 and $2,000, but you’ll pay much more if you’re installing a new skylight into an existing roof.
