Energy Ratings

The British Fenestration Rating Council (BFRC) energy performance label can help you determine how well a product will perform the functions of:

• Helping you contain and conserve heat within your building in the winter
• Cool it in summer
• Keep out the wind and resist condensation

By using the information contained on the label, builders and consumers can reliably compare one product with another and make informed decisions regarding the energy performance of window products.
The basic label lists the manufacturer, describes the product, includes the essential energy performance data and provides a source for additional information.

Thermal transmittance (U-value) This measures how well a product prevents heat escaping. The energy rating value is based on a standard window to enable comparisson of product. This does not represent the actual energy efficiency for actual product installed. The BFRC Rating is calculated from the formula: Rating = 218.6 x g-value - 68.5 (U-value +L50)

Solar Factor (g-value) This measures how well a product blocks heat caused by sunlight. The Solar Factor is expressed as a number between 0 and 1. A lower Solar Factor means less heat gain.

Air Leakage (L50 value) The factor L50 in the formula is an air leakage factor. For good quality windows, air leakage makes little difference to energy performance, for leaky windows, the impact is significant.

Each rating label is specific to a manufacturer and is non-transferable. The BFRC Certificate Number relates to the specific certificate and details of the certificate can be obtained from this web site. The BFRC rating is provided for a standard window to represent typical window sizes. The size is 1.48 x 1.23 m. This enable comparission between different products.
The BFRC is a collaborative venture between all stakeholders in the windows industry. It was established in 1998 with the assistance of the DETR and the major trade associations from the window industry.
Our objective is to create and maintain a "fair, accurate and credible" rating system to impartially measure and assess the thermal efficiency of windows.
In developing the BFRC Rating, the BFRC is advancing new methods of energy assessment for window products.