What are Double Hung Windows?
A double hung window has two operable sashes that move up and down. The sashes slide in tracks built into the frame and are held in position by either counterweights, springs, or friction. The sashes are locked shut with a latch located where they meet in the middle. Double hung windows are associated with a more traditional aesthetic and often have simulated divided lights, or window grids installed. A double hung window that has a top sash narrower than the bottom sash is sometimes called a cottage window.
Double hung windows have certain advantages over single hung windows, which have a stationary top sash. Double hung windows are an easy type of window to keep clean because both sashes tilt in for easy access to the inner and outer surfaces of the glass. Lowering a top sash allows heat to more easily escape from a room. Also, if a window is located directly below a projecting eave, lowering the top sash may still be an option even during a rainfall.