What’s the difference between a casement window and a double-hung window? Both window styles 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 the glass window panes. All Improveit windows are designed to open smoothly and easily, year after year. However, casement windows operate with a crank handle, while double-hung window sashes must be lifted (bottom sash) or pulled down (top sash) to open, which can require more leverage or strength for some users.