High energy performance glazing have low U values. The lower the U value, the less heat is lost from the inside and the more insulation the glazing provides. Across all climates, low U value glazing are recommended.

Ug values of high energy performance glazing typically range between 1.4 and 0.5, corresponding to window Uw values between 1.5 and 0.7.

 

The g value expresses the amount of solar heat that passes through the glazing. Depending on the climate, the window size and the glazing exposition, choosing the most appropriate g value will ensure comfort and energy savings depending on needs.

 

A high g value means the glazing will capture more free solar heat gains, while a lower g value indicates most solar heat gains will be repealed to avoid over-heating.