What organization establishes energy performance ratings for windows?

The National Fenestration Rating Council (NFRC) is the organization responsible for establishing energy performance ratings for windows. NFRC’s primary role is to provide accurate and credible energy performance ratings that allow consumers to compare the energy efficiency of different window products. This encompasses factors such as U-factor, Solar Heat Gain Coefficient (SHGC), and Visible Transmittance (VT). These ratings help in understanding how well a window insulates, how much solar heat it allows in, and how much daylight it transmits, which are essential for making energy-efficient choices in construction or renovation projects.

Organizations like ASHRAE and NIST focus on broader guidelines and standards related to energy efficiency and building performance, but they do not specifically rate window performance. Energy Star, while a well-known certification program, relies on NFRC ratings among other criteria for the windows it certifies, but it is not the organization that directly establishes the performance ratings.