Quality & Accreditations
Members of FENSA Certification
Window Energy Ratings Certification
Conventional approaches (such as setting a glass or window U-value) simply assess how much energy a window loses. They do not take into account how much energy a window can gain.
The total energy flow in a window consists of three major components:
- Thermal transmittance (U-value)
- Solar factor (g-value)
- Air Leakage (L50)
The British Fenestration Ratings Council (BFRC) has devised a Window Ratings equation based on values for these components. The rating is expressed as a number. The rating is converted into a grade between A and G (with A being the most energy efficient).