A single-hung window, also known as a single-sash window, is a type of window with a lower, operable sash and an upper, fixed sash. This means that the bottom part of the window slides up and down, while the top part remains stationary. Single-hung windows provide ventilation through the bottom sash.

Why use single hung windows?

With only one movable sash, there is less opportunity for air infiltration as the window ages. Installing replacement single hung windows also increases the energy efficiency of your home, as newer windows feature improved technology—including more energy efficient glass, frame, insulation, and more.

What's the difference between a double hung window and a single hung window?

The main difference between a single hung and a double hung window is how the two operate. A single hung window has a fixed top sash and an operable bottom sash that moves vertically. In a double hung window, both the top and bottom sashes are operable.