What Does U-Factor Mean?

What Does U-Factor Mean?

ENERGY STAR® qualified windows are independently tested and certified by testing procedures established by the NFRC (National Fenestration Rating Council.) Included in the five categories of performance ratings on an NFRC label is U-Factor.

U-Factor measures the rate of heat transfer and indicates how well the window insulates. This measurement represents both heat loss during cold weather and heat gain during warm weather. U-Factor takes into consideration conductance, airflow around the window and the radiated or reflected heat of the glass. U-Factor values generally range from 0.20 to 1.20. If figuring out all the performance numbers seems confusing, just remember that the lower the U-Factor, the better the insulating power!

Harvey windows and doors qualify for ENERGY STAR because we are an ENERGY STAR Partner, our windows have been independently tested, and they have NFRC ratings that meet the guidelines set by the U.S. Department of Energy. ENERGY STAR’s color-coded climate zone map shows performance criteria for each climate zone, including the colder Northern region where we manufacture and test Harvey windows and doors.

Our thermal performance guide provides data for Harvey windows and doors, and includes U-Factor, Solar Heat Gain Coefficient (SHGc), and Visible Transmittance (VT). Visit our ENERGY STAR page for further information about all of the performance categories, and if you’re ready to speak with a contractor about Harvey windows and doors for your home, visit the Harvey ProZone® to help find a local Harvey contractor.