Casement window

A casement window is one of the oldest window styles in continuous use, predating the double-hung sash window by several centuries, and one of the most underrated for modern residential use. The form is simple: the window pane is set in a frame that hinges on one vertical side, and the whole window swings outward like a door, typically operated by a crank handle on the inside. Casements provide several real advantages over the more common American double-hung window, but require some thought about where they fit.

Origin

Casement windows were the dominant window style in Europe for centuries, used in everything from medieval castles to colonial farmhouses to grand 19th-century English manor houses. The form predates the more complex double-hung sash window (which became standard in American residential construction in the 18th century). In England and continental Europe, casement windows have remained the dominant style continuously. In the US, casement use declined through the late 19th and early 20th centuries as double-hung windows became the norm, partly because double-hungs work better with window screens, and screens became important in mosquito-affected regions.

How casements differ from other windows

• Casement, hinges on one side, swings outward, operated by crank
• Double-hung (sash), slides vertically, with both an upper and lower sash that can move
• Single-hung, like double-hung but only the lower sash moves
• Slider, slides horizontally
• Awning, hinges on the top, swings outward at the bottom
• Hopper, hinges on the bottom, swings inward at the top
• Fixed, doesn't open at all (picture window)

Advantages over double-hung

• Better seal when closed, the sash seals against the frame on all four sides via compression; double-hungs seal at the meeting rail only
• More ventilation per pane size, the entire window opens, vs only half on double-hung
• Catches breezes, when angled, casements can scoop air into the house from any direction
• Easier to clean from inside, most modern casements pivot enough to access the exterior glass from inside
• Often more energy-efficient, better seal means less air infiltration
• Better for tall narrow openings where a double-hung would have a small sash

Disadvantages and challenges

• Cannot be screened on the outside, screens go on the inside, between the sash and the interior, which affects look and feel
• Outdoor-swinging sash interferes with walkways, decks, or anywhere people are outside the window
• Crank mechanisms can fail over years and require service
• In high wind, open casements can slam shut or be damaged
• More expensive than double-hungs for equivalent quality

Where they work well

• Kitchen above the sink, easy to crank open while standing at the sink for fresh air
• Bathrooms, better seal helps with moisture and steam control
• Bedrooms, better seal means quieter sleeping environment near busy streets
• Tall narrow openings, casements scale to tall narrow openings better than double-hungs
• Modern architectural homes, clean rectangular casements fit modernist aesthetics better than divided-light double-hungs
• Where breezes from a specific direction are desired, casements can scoop air

Modern variants and styles

Contemporary casement windows come in several variations:

• Single casement, one pane, one hinge side
• French casement, two casements meeting in the middle with no center post, swinging outward like French doors
• Multi-light divided casement, multiple smaller panes within a casement frame, traditional in older homes
• Steel-framed casement, slim industrial-look casements, popular in modern and industrial-influenced interiors
• Combination, casement paired with fixed picture windows on the sides

Style considerations

Casements pair particularly well with:

• European-influenced architecture (English country, French country, Mediterranean)
• Modernist and contemporary architecture (especially steel-framed casements)
• Cottage and farmhouse interiors
• Industrial-style interiors (steel casements with divided lights)

They work less well in strictly American traditional homes (where double-hungs feel more authentic), in spaces where you need exterior screens, or where outdoor space directly outside the window is heavily used.

Related window types

Casements are part of a vocabulary of operable windows that includes double-hung, awning, hopper, slider, transom (small window above doors), and tilt-and-turn (European hybrid that opens both as a casement and as a hopper). For full architectural style, casement windows usually pair with French doors, French casement doors, and divided-light fixed windows.