Window energy ratings (Energy Efficient Glass)

Window Energy Ratings were launched in early 2004 by the British Fenestration Rating Council (BFRC), an independent organisation dedicated to improving the energy efficiency of windows.

A window's rating is determined by a formula which takes into account available solar heat gains (window g-value) and subtracts the thermal losses (window U-value and air leakage).

WERs = Solar Gains - (Thermal Losses + Air Leakage)

The resulting value (Energy Index) is then placed into a band on an A-G scale consistent with other energy performance labels already familiar to the consumer.

 

Detailed information on obtaining Window Energy Ratings can be found on the BFRC website: www.bfrc.org