Sure the United States is a country that’s big on scale and large gestures. But I have to say that I love small moves that make a big difference. Sometimes it’s as simple as changing a color. Sometimes it’s adding a strategically placed window or removing a poorly placed wall. One of the best small moves is adding a bay window to a room. Whether it’s a box bay, an angled bay, a walk-out bay or a bay with a window seat, a bay window can add depth and dimension and light to a dark and cramped space.

While not every installation is a DIY weekend project, installing a bay window is relatively affordable, especially if you’re handy. For a few thousand dollars, you can dramatically alter a bedroom, living room or home office while giving yourself that extra few feet for a sofa, desk or piano.

The Box Bay

A box bay is, quite literally, a box attached to the ground floor of a house. It is a simple, rectangular form that has side walls perpendicular to the wall of the house. While a box bay typically has a group of windows at its front, windows on its two sides aren’t a requirement. And don’t think of a box bay as just a box. A gently curved roof over a bay, as shown here, can add style and elegance. Not only will a box bay add an abundance of light to the interior, but it will maximize the amount of floor space added. So if you’re thinking of adding a sitting area, space for a desk, room for a piano or a nook for a game table, a box bay is something you should consider.

Budget: While bow and angled bays come preassembled, a box bay is typically built onsite. While this will give you latitude in size and other design considerations, it also means that a box bay will cost more. You could invest as little as a few thousand dollars, but a reasonably sized box bay with good- to better-quality windows and a simple structure will cost around $10,000 to $15,000.

The Oriel Window

A bay window of any type that doesn’t reach the ground is typically called an oriel window. The shape isn’t as important as the upper-story location. So an oriel can be referred to as an angled, box, bow etc. bay window. Keep in mind that an oriel is not a simple second-floor cantilever. It has a visually distinctive appearance that will be compatible with the structure while not being exactly the same. And an oriel is typically supported on brackets or something else that gives it the appearance of being hung on the house. An oriel window, because it’s located at an upper floor, is a terrific way to expand a second-floor bedroom or study. And by strategically placing the oriel, you can provide a covering to the first-floor entry area.

Budget: An oriel can be a very cost-effective way to expand your home, especially if the bedrooms are small. In fact, if you have carpentry skills and some help, an oriel can be a nice little DIY project. Like other bays, it can cost a few thousand dollars to much more, depending on size, structure, materials etc. It should, however, cost less than a first-floor bay, as an oriel doesn’t need any foundation work. And a good tip is to place an oriel in a location where a group of windows exist, so there’s no new header requirement.

The Angled Bay Window

Named because the side walls of the bay are angled, an angled bay is probably the image that comes to mind when someone says “bay window.” It’s just about the most ubiquitous bay window there is, especially as versions of it, at least the smaller, preassembled ones, are sold by the scores by the big-box retailers. A bigger angled bay will have to be built onsite and will likely require a foundation. Certainly a larger angled bay will work wonders for a room. And the beauty of these types of bays is that they really do reach out to the landscape, bringing in all of that wonderful natural light and views.While an angled bay that’s large and can be walked into will work magic in a home, a small, preassembled angled bay above a kitchen sink will totally change the dynamics of a kitchen.

Budget: While site-built, custom angled bays can cost well into five figures, a smaller, preassembled bay can be a cost-effective way to get some extra space and light into your home. Many preassembled angled bays sell for less than $1,000, so it won’t take much to change your interior with one of these.

The Bow Window and Circle Bay Window

Aptly named because of its bowed shape, the bow bay introduces a soft and relaxed geometry to an overall scheme. Bow bays are typically large to provide for a generous and sweeping arc of an exterior wall. A circle bay, on the other hand, will have a tight radius and so is typically smaller. Note that the second-floor circle bay above the entry steps here is an oriel window. If it had been placed at the first floor, it would be called a circle bay. Bow bays and circle bays are typically all window, bringing a lot of light and view into the interior while expanding the footprint just enough to prevent a space from feeling too small.

Budget: If you’re looking to dramatically change a room and are handy, you can install a bow bay for around $1,500 to $,2000.