Exova BM TRADA is approved as an Independent Agency for the BFRC (British Fenestration Ratings Council). Our Window Energy Ratings certification scheme allows manufacturers to apply to use the energy rating label on their products.
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).