Window Types

Though some windows are fixed in their frames, most open and close. The parts that move up and down, side to side, or in or out, are called sashes. All types can include the efficient technologies that deliver benefits such as lower household monthly utility bills. These are the most popular options:

Single-hung windows have two sashes: a fixed one in the top half of the window, and a sliding one on the bottom that moves up or down.  

Double-hung windows have two sliding sashes. The top sash can be lowered and the bottom sash can be raised, providing the choice of which parts of a window to leave open.

Sliding windows have sashes that slide from side to side. This category includes sliding doors common for yards and patios.

Casement windows have hinges on the sides of their sashes, and open by swinging out or in.

Awning windows have hinges on the top of their sashes, and swing out from the bottom.

Fixed windows don’t open. 

Skylights are light-permitting windows that are placed on a home’s roof, providing natural light and ventilation. More on skylights.

About Us

provides unbiased information and education to the public on the energy efficiency, technical, and human considerations that influence window selection and use. The EWC collaborates with allied organizations, educational institutions, and government agencies that promote energy efficiency in residential windows. We do not sell, service, install, or recommend products, or endorse manufacturers. Descriptions and specifications of the products in the Window Selection Tool are provided by the manufacturer. The EWC is not liable for any manufacturing defects or inaccurate product descriptions and specifications and does not guarantee the performance of NFRC-certified windows, doors, and skylights.

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