U-Value & SHGC Explained

Windows and doors connect our internal living spaces with the outdoors. With this they can potentially lead to unwanted heat gain in summers and cause substantial heat loss during winters.

As the awareness around energy efficiency is increasing, new homes and renovation projects are required to meet with given energy rating or star value. In order to achieve this rating, our aluminium windows and doors need to comply with the laid down performance values for energy efficiency. The terminology that we use to describe these performance values is known as U-value and Solar Hear Gain Co-efficient (SHGC).



The U-value measures how well a product prevents heat conducting through the whole window (frame and glass). It does not factor in solar heat from direct sunlight. A lower U-value is considered better i.e. the aluminium frame (including glass) with a low u-value has a higher resistance to heat flow and has a higher insulating value. To comply with energy rating reports, U-values must be equal to or lower than specified. Generally, U- values in Australia fall between 2.0-10.0 W/m2.K. U-values are affected by the type of glass used.



SHGC is a measure of how freely solar heat passes through a window or door. The lower the number the less solar heat it transmits. Windows that have a high SHGC, allow a greater amount of solar radiation to be transmitted, absorbed and eventually released inside the house. This essentially translates that such glass units cause your home or building to heat up quicker. To comply with energy reports, the SHGC must be within 10% of the set value. SHGC is expressed as a number between 0 and 1. The type of glass selected (laminated, toughened, tinted etc.) can greatly affect the SHGC rating.

Due to the high number of glass and window combinations we cannot show you all of the ratings here. But if you would like to know more, please feel free to contact us as our team is adept with this technical knowledge. Moreover, navigating the WERS website for ratings can be difficult and overwhelming, if you don’t know what to look for.