What is a bay window?

With its combination of windows that extend beyond the exterior walls, a bay window has some unique advantages. Here are a few you’ll want to note:

• Curb appeal! A bay window is memorable, and in some cases, it’s the signature feature on a home’s exterior.
• Natural light: With multiple windows in one unit, there’s a large amount of glass set at a variety of angles, which allows in more light overall.
• Panoramic views: The projecting design with windows facing multiple directions allows you to take in more of the landscape.
• Living space: The bay creates additional space on the inside — either through a shelf that’s perfect for pets and plants or actual square footage, depending on the style chosen.

Our 400 Series Bay Windows and E-Series Bay Windows are available with flanking windows at 30°, 45°, or 90° angles. When deciding on the right angle for your windows, take the following into consideration:

• How much space do you have outside? If you have a postage-stamp size yard, a 30° or 45° angle will likely be the better option, so you can preserve some outdoor space while still creating a pleasant nook on the interior. If you want a round window with a more subtle exterior protrusion, a 400 Series Bow Window is another good option.
• Is your home more modern or more traditional? Of course, there are always exceptions, but generally, a box bay, where flanking windows are at 90°, creates clean lines suiting a more modern home. The trapezoidal shape created by flanking windows at 30° or 45° suits a more traditional home.
• What’s happening on your interior? Will you be using the space created by your bay window to house furniture? If so, a box bay with flanking windows at 90° would better maximize your space. Think about how the window will function in the room and your goals for it when selecting the ideal angle.

As you consider the ideal angle for your bay window, don’t forget to consider which type of flanking window will be most practical. Remember that casements are crank operated, making them easy to open when you’re reaching. A double-hung can work well in a bay where you’ll have easy access to the windows.

If you think you want a bay window in your new construction home, there are a few challenges to take into consideration when preparing for installation, and the installation itself:

• How will the unit be supported? If your bay window is going to be cantilevered from the home without sub-unit support, you will need to use cables. These cables will have to be anchored to the home, typically into ledgers for floor joists. Another way to support the units is by building a supporting knee wall that follows under the path of the unit. This is usually the desired method for bay windows that extend to the foundation, because the seat board is no longer necessary to provide support. In this method, the wall itself holds up the unit, allowing for the walkout area.
• How will the cables be covered? If you have cables, they will need to be covered up, along with the head of the unit. Typically, this can be done using a hollow pseudo roof that the cables can pass through.
• How will you determine the size? Bay window sizing is unusual because the head and seat board are not calculated into the overall unit height. 

If you’re replacing a bay or bow window, you will need to think about some different challenges, including whether you want to match what’s already existing (cable or wall support) or if you want to change it. If you want to change it, you’ll need to know whether you have the proper structural support for the project type you have in mind. For example, if you want a bay that goes to your foundation, you need to know if you have the ability to open up a wall and frame it out to support it.

Both bay and bow windows include large expanses of glass since they’re made of at least three windows. Glass will never be as energy efficient as a wall, but here are some selections you can make to improve the energy efficiency of your bay or bow window:

• Choose the right glass options: Low-E glass coatings increase the performance of windows by reflecting or absorbing heat. The coatings are ultra-thin, generally transparent, and the best part is that a Low-E coating comes standard with our windows. If you want to further enhance window performance, you could select casements for the flanking windows as their single-sash design seals in a way that helps improves efficiency.
• Add insulation: The energy efficiency of bay windows can be improved by adding insulation at the header and below the seat board (the shelf built into a bay). This is something your builder or contractor can do during installation.
• Skip the grilles: When they touch both panes of glass, grilles can conduct energy and help decrease the insulating power of air space. Various products are available with energy spacer bars that avoid touching the glass if you want to include grilles.
• Prevent condensation: One of the best ways to help prevent condensation on the inside of a bay window is by reducing indoor humidity. You can reduce humidity with proper ventilation and by using a fan to promote air movement. Learn more about condensation.

Find out more about how to pick out energy-efficient windows.

Finally, if you are looking for a more energy-efficient solution, you could consider a picture window rather than a bay or bow window. Picture windows are the most efficient window type because they don’t open, and their large sizes could create a similar feel to a bay or bow. Just keep in mind that the bigger you go, the less energy-efficient it will be since glass is less efficient than a wall.  When trying to strike a balance between windows and energy efficiency, your architect or builder will be able to help. 

Because bay windows include multiple windows facing various angles, they offer ample opportunity to add natural light to your home. There are a few ways to maximize this advantage:

• Size: This might go without saying, but the larger your bay window, the more light will enter your home. Consider adding more than the standard three or four windows to your bay if you have the space.
• Location: South-facing windows will maximize natural light in a home. Consider what rooms you use the most, and if possible, add a south-facing bay window to the room with the most traffic.
• Style: The picture window in the center of your bay window unit offers the perfect opportunity for maximizing natural light. This is because picture windows can more easily be made oversize, due to the fact that they don’t open. When choosing the flanking windows, opt for sleek frames and no grilles. A casement window with its single-sash will offer more clear glass than the alternative, which is a double-hung and therefore has a check rail (where the lock is) across its center.