How They Work
A window that
opens like a door
A casement is hinged on one side and opens outward with a crank or a push handle. The whole sash swings clear, so the full opening ventilates instead of half of it, and an open sash can catch a crosswind and steer it into the room.
When it closes, the lock pulls the sash tight against weatherstripping all the way around. That compression seal keeps out wind-driven fog and rain far better than a sliding seal, and it noticeably cuts street noise.
