Sash Windows

A sash window is a window that is made of several movable panels, known as sashes. These form a frame that holds panes of glass together, which are themselves separated by astragal bars. Sash windows are operated by sliding a sash open either vertically or horizontally.

To facilitate operation, the weight of the glazed panel is usually balanced by a heavy steel, lead, or cast-iron sash weight or counter-weight concealed within the window frame. The sash weight is connected to the window by a braided cotton sash cord, or a chain, that runs over a pulley at the top of the frame, although spring balances are sometimes used. Repairing a broken cord requires disassembling parts of the window frame.

Sash windows may be fitted with simplex hinges, which allow the window to be locked into hinges on one side while the counterbalance on the other side is detached, allowing the window to be opened for escape or cleaning.