In architectural terms, energy efficiency refers to a window or door’s ability to resist unwanted thermal transfer, keeping your interior climate stable. This is primarily measured by the U-Value (Thermal Transmittance).
The U-Value quantifies the rate of heat loss through a building element; the lower the U-Value, the better the insulation performance of the window assembly. Specifying products with low U-Values is essential for reducing carbon footprints, complying with local codes (such as NCC Section J), and significantly lowering monthly HVAC heating and cooling costs. For a deeper dive into localized star ratings, you can view official educational resources from the Australian Glass & Window Association (AGWA) or consult our technical desk.