The difference between Casement and Sash windows: The big difference between Casement and Sash windows are the way they open. Sash windows slide vertically in the frame and occasionally horizontally. Casement windows open outwards or inwards via hinges on either the side, top or bottom of the frame.   Build and cost Sash windows are more complex in the way there are built with a counter weight on a rope either in one side or both sides of the frame to ease the movement and counter balance the opening. This often makes the frames thicker than Casement windows. Some of…