16 Types of Windows

Sash windows are made up of movable "sash" panels that serve as frames for panes of glass. Single-hung sash windows refer to those with a fixed top sash and a movable bottom sash panel that can be adjusted up or down to regulate air flow. Double-hung sash windows are those in which both sash panels can be adjusted for even better ventilation. Sash windows have been around since they appeared in Britain and continental Europe in the 1600s. A hallmark of Victorian and Georgian architecture, they remain ubiquitous today.

In this bedroom design from Seattle-based OreStudios, a tall rectangular fixed plate glass picture window lets in ample natural light while showcasing the view outside like an oversize work of art. While picture windows are designed without panes or other details to obstruct views and do not open, letting in light but not air, sliding glass doors on an adjacent wall here open to let in the breeze.

Casement windows refer to any window equipped with a hinge on the side that allows the window pane to swing open. This hugely popular window type allows for unobstructed views when the windows are open.

In NYC, the term "casement windows" has become a real estate marketing term that refers to the black metal-framed gridded windows that often characterize industrial architecture and prewar apartment blocks. With their square geometric black window panes, these striking windows have become iconic, both in period buildings and new builds thanks to the ever-rising popularity of industrial chic design and the widespread repurposing of disused industrial architecture throughout the world.

A bay window is a central window or group of windows flanked by additional windows that jut out from a building's walls and create a "bay" inside a room. Curved bay windows are called bow windows. Bay windows add scene-stealing character to any room as well as a luxurious amount of natural light. A hallmark of Victorian architecture, they also add interest to a building's exterior. The oversized bay windows in this spacious eat-in kitchen designed by Seattle-based OreStudios allow natural light to flood the space and show off an impressive view.

Dormer-style windows protrude from the roof of a house. A dormer window might be used to provide natural light and therefore increase usable space in an attic, and can be found in various styles of architecture around the world, from the top floor former maids rooms in mansard-roofed Parisian apartment buildings, where dormer windows first became popularized, to Cape Cod cottages with pitched roofs.

French windows are vertically split down the middle and open on both sides, like the windows on these Parisian apartment buildings. In some cases, French windows open onto a balcony and are used as both windows and doors. French or double doors with glass panes or one clear pane of glass are also widely used around the world in interior spaces to separate rooms while maintaining light and partial views. French window doors might be used to separate a home office from the main living space, to connect a kitchen to a deck, or a living room to an outdoor patio. French windows and doors can be made out of wood, metal, or more frequently today, vinyl.

If you've got a spectacular view and adjoining outdoor space, there's no better way to flaunt it than with large expanses of glass that facilitate indoor-outdoor living. In this serene living room designed by Seattle-based OreStudios, floor-to-ceiling sliding glass doors open up to the outside and offer light and stunning views from within.

A skylight window is essentially a window for your roof. In this attic home office located in a house with a pitched roof, a large skylight allows light to flood in and air to circulate, making what might have been lost square footage into usable space. Skylights can also be used on a flat ceiling beneath the roof to allow natural light to flow into a dark hallway or a bathroom lacking light, or anywhere else that could benefit from natural light.

The use of round windows in architecture dates back to the 16th century. The French began incorporating circular dormer windows into architecture in the 17th century. The French term for rounded windows, oeil de boeuf (bull's eye), is still used today. Round windows are charming and picturesque, reminiscent of the portholes on a ship. In this Swedish bedroom, a round window creates a focal point in an otherwise tiny attic space.

Stained glass is an ancient technique dating back to the Romans and Egyptians. Colorful glass depicting scenes were used to tell visual stories to a largely illiterate public in the medieval churches of Europe and grew larger and more ornate as a feature of Gothic cathedrals. They are a popular feature of Victorian era homes in Britain and the United States.

Arched windows date back to Roman times. Lancet windows with pointed arches are a feature of many of the world's great Gothic-style cathedrals. But today you're likely to find this curvy window variation as a feature of traditional-style homes or new construction to create architectural interest with an alternative to standard rectangular window shapes.

In contemporary office or apartment buildings, glass window walls are often used to allow as much natural light as possible to penetrate inside while protecting against the elements such as rain, wind, and seismic sways. These windows offer expansive views to the outside and an airy feeling inside, but when used in dense urban areas they can create a fishbowl effect that can make living in them uncomfortable. Their large scale makes energy efficiency a challenge depending on the climate and appropriate window treatments expensive. And of course it requires herculean maintenance to keep them clean inside and out.

Atelier windows refer to the fixed black steel-framed windows historically found in the storied studios of famous 20th century artists that allow maximum natural light to penetrate indoors—but you don't have to be a painter to appreciate this window style. In France, you can find both original atelier windows in period buildings and a more recent trend in which a verrière d'intérieur might be used to partially separate adjoining spaces—such as a kitchen and living room or master bedroom and ensuite bathroom—while adding architectural interest. This industrial style has become popular elsewhere around the globe both in residential interiors and open-plan offices where glass partition walls allow open sightlines with a modicum of privacy, allow natural light to flow through deep spaces, and provide acoustic insulation. Atelier windows are generally fixed but may include panes that open or incorporate doors.

Transom windows or transom lights refer to the horizontal bar-like windows placed over door frames to allow extra natural light to flood in, and can be used either indoors as seen here or above and/or on the sides of exterior doors. This architectural trick dates back to the 14th century, and in the case of front doors, allows light to penetrate into an entryway while being high up enough to maintain privacy. The term is also used to describe horizontal windows placed high in spaces like bathrooms or bedrooms that increase light and/or ventilation while keeping neighboring eyes from peering in.

A fanlight is a variation of the transom window. A semi-circular decorative window whose bars create a fan-like appearance, fanlights allow extra light to flood in while creating an architectural flourish on a building façade. Fanlight windows are also sometimes referred to as sunburst windows.