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Why Should I Know About Solar Heat Gain Coefficients?

What does solar heat gain coefficient mean?

And why is it something I should know? Solar gain

(also known as solar heat gain or passive solar gain) is defined as the rising temperature in a space, object or structure (a window, for example) coming from solar radiation. The strength of the sun and the ability of the structure influence that object’s resistance to the radiation.

When a window is struck by sunlight, it absorbs short-wave radiation from the light and emits heat. The solar heat gain coefficient (SHGC) measures the ability of a window to block solar heat. The SHGC refers to the fraction of the heat from the sun that passes through a window. The solar heat gain coefficient is expressed as a decimal between 0 and 1. The smaller a window’s solar heat gain coefficient, the less heat from sunlight is allowed the space.

A diagram of solar heat transmitting through a window.

A diagram of solar heat transmitting through a window.

Understanding the SHGC can help dramatically reduce energy costs that deal with heating and cooling concerns. Higher SHGCs are beneficial for colder climates, whereas lower SHGCs are beneficial for warmer climates. The solar heat gain coefficient can be found on the National Fenestration Rating Council label that is attached to the product by the manufacturer.

For more information regarding energy efficient products, contact FASDoors at 1-888-422-1960. If you have any questions you’d like to submit online, you can always ask our FAS expert! Call us today to schedule your FREE in-home estimate!

Katie Pettit 9/23/2010

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