Window energy ratings (Energy Efficient Glass)

The overall WERs performance of a window is dependent on the combined effect of the frame and glazing components and the air-tightness of the finished window. Ratings may be improved by decreasing thermal losses and/or by increasing passive solar heat gain.

Decreasing Thermal Losses

Type of low-E glass

Choosing a new generation high performance low-E glass such as SGG PLANITHERM TOTAL can help significantly reduce thermal losses compared to traditional low-E products.

Inert gas filling

Argon gas filling a double-glazed unit further reduces heat loss.

Optimised cavity width

The optimum cavity width for an argon filled unit is 15mm (10mm with krypton).

 

 

Increasing Passive Solar Heat Gain

Low-iron glass

Has been specially manufactured to be significantly clearer than standard glass allowing better transmission of solar heat and light.

Increasing the sighted glass area

By changing the frame design to maximise the proportion of glass in the window allows for greater area through which solar heat gain can be transmitted.