What’s the difference between a casement window and a double-hung window? Both windows are taller than they are wide, but casement windows swing open from side-mounted hinges, while double-hung sashes move up and down within the frame. When a casement window is fully open, the entire window opening is completely unobstructed. However, a double-hung window will always have at least half of the window area blocked by glass window panes. Additionally, casement windows operate with a crank handle, while double-hung window sashes must be lifted (bottom sash) or pulled down (top sash) to open. This can require more leverage or strength compared to cranking open a casement window.