What is a casement window?

A casement window, also referred as a crank-out window, has a single sash that opens outward on a vertical axis by rotating a crank that is attached to the sash with heavy duty hinges. The hinges can open the sash to a full 90 degrees allowing or easy cleaning from inside the home. A multipoint locking system closes the unit tightly from a single lever. The casement is the most energy efficient of all operable window styles. Casements may be joined together into double, triple, or quadruple units.