This classic yet modern design of the casement window is a perfect addition to properties both old and new. A clean, unfussy appearance is simple in looks and use. A casement window has a casement sash attached to a timber frame by hinges on one side and opens outwards or inwards. Casements are usually hinged at the side but they can be hinged at the top or the bottom of the window. Because of their draught sealing system, casements are airtight when closed which means they have very low air leakage rates.