Independently rated by WERS.

The Window Energy Rating Scheme (WERS) provides a scientifically based and credible energy rating system that is managed by the Australian Window Association. Energy Ratings provided by WERS are third-party certified, compliant with the National Construction Code (NCC), and are used to meet regulatory requirements. Rylock’s WERS report lists various values for windows including the U value and SHGC.

U value

U-value measures how well a product prevents heat from escaping. It is a measure of the rate of non-solar heat loss or gain through a material or assembly. The rate of heat is indicated in the terms of the U-value of a window assembly which includes the effect of the frame, glass, seals and any spacers. The lower the U-value, the greater a window’s resistance to heat flow and the better its insulating value.


The Solar Heat Gain Coefficient (SHGC) measures how well a product blocks heat caused by sunlight. The SHGC is the fraction of incident solar radiation admitted through a window, both directly transmitted, and absorbed and subsequently released inward. SHGC is expressed as a number between 0 and 1. The lower a window’s SHGC, the less solar heat it transmits.

In order to comply, the window system must perform to the set parameters. Importantly, these values are ‘whole window values’, not glass alone. Rylock’s custom ratings are produced for a variety of different glass types.

WERS ratings

WERS Results