What is a casement window?

A casement window is a sash window hinged on one or both vertical sides that swings outward to open, typically operated by turning a crank handle or pushing a lever on the frame's interior. Unlike sliding or double-hung styles, casement sashes project open to the outside, which allows the entire sash area to function as an unobstructed opening.

Casement windows form a tighter seal against weather when closed because the sash swings shut and presses the weatherstripping firmly into the frame. This makes them a common choice in Connecticut homes where winter wind and moisture ingress matter. Single and paired casements are both common, with paired models often used across wider openings to distribute weight and operation more evenly.

The crank mechanism can wear over time, and the sashes may sag or bind if the frame settlement occurs. When casements are part of a full replacement-windows project, installers typically ensure proper frame squareness and hinge adjustment to preserve smooth operation. The outward swing also means clearance beyond the window must be clear, which affects placement in kitchens, decks, or other tight spaces.