How to read a window label
Window labels contain wealth of knowledge about energy efficiency and performance of the window. National Fenestration Rating Council is the most important label to look at. It`s an independent window and door third party rating organization. Replacement windows CT
A – U-Factor or U-Value. It describes the amount of heat flow and usually falls between 0.15 and 1.20. The lower the number is the better the window is at resisting heat escaping from your house during winter. Professionals considered this number the most important factor of window performance.
B – Solar Heat Gain Coefficient. Also known as SHGC. It determines the how much long-wave ultraviolet radiation is admitted trough your window. Again the lower the number the better the window is at keeping heat out during the summer. Usually it falls between 0 and 1.
C – Visible Transmittance. It`s the amount of sunlight (daylight) that is passing through your windows. The higher the number the more light is admitted to your home. Normally the number can be anywhere between 0 and 1.
B – Solar Heat Gain Coefficient. Also known as SHGC. It determines the how much long-wave ultraviolet radiation is admitted trough your window. Again the lower the number the better the window is at keeping heat out during the summer. Usually it falls between 0 and 1.
C – Visible Transmittance. It`s the amount of sunlight (daylight) that is passing through your windows. The higher the number the more light is admitted to your home. Normally the number can be anywhere between 0 and 1.
