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Is It a Bay or a Bow Window?

When a window projects from the face of a house, we call it a bay or a bow window. What is the difference between these two types of windows and why does it matter?

A Bay Window

bay window

A bay window is two angled windows flanking a picture window parallel with the wall of the house. It is square, hexagonal or octagonal in shape and can look like an addition or alcove on the home. Typically, the front window is fixed window while the side windows are operable, letting in air. They can protrude far from the face of the building so can extend your views.

A bay window is a good solution when you’d like a little more space in a room, increased natural light and expanded views.

A Bow Window
bow window

A bow window is typically 4 or more casement windows that create a curve; an odd number of windows tends to create a more graceful bow. It gives the effect of one large window rather than an architectural element on the building, like a bay window. All or some of the windows can be operable for ventilation. Bow windows tend to let in more light and can project out far enough to include a window seat.

Bay or Bow – Why Does It Matter?

The difference between these two types of windows are important to builders and designers because it helps them determine the cost of your project and how long it will take to complete it.

Builders need to know how it will be constructed. Because a bay window can protrude deeply outside of the building they can add floor space to a room. When they are used like an addition, typical building practices for walls and roofs are required. This can substantially increase the cost of the project as it becomes a small room rather than a window.

Bows have more windows than a bay, which can raise the price, but they can be bought as a per-fabricated unit that bolts to the house, which makes it closer in price to a window installation than new construction.

For designers, the architectural style of the rest of the home and the purpose of the window helps determine if a bow or bay is more appropriate. Bow windows work well in large openings of 7’ or wider where the multiple windows can create a sleek curve, so they can blend well with more contemporary or modern homes. Bows can also provide shallow bench seating with storage.

furniture in bay window


If you want a little more space in a room, the bay window may be the better choice as it can be designed like a small room addition (like above). Its angled geometry and historic connotations make it a better choice for more traditional architectural styles. Let your designer know what your needs and desires are for the room and they will help you determine which type of window will work best.

To explore your bay or bow window options in the metropolitan St. Louis area, call the designers and builders at Mosby Building Arts at 314.909.1800 or contact them here.