Understanding Window Energy Ratings

The British Fenestration Rating Council’s Domestic Window Energy Rating Scheme provides a way to compare the energy performance of windows.

Windows that achieve a C rating or higher can carry the ‘Energy Saving Recommended’ tag. All our Energy Efficient windows achieve C rated or better energy efficiency.

The detail

Thermal transmittance

This measures how well a product prevents heat escaping.

Solar Factor

This measures how well a product blocks heat caused by sunlight.

Air Leakage

This relates to the volume of air leakage from a window.

Lower numbers achieve a higher rating (A to G).