When selecting aluminium windows and aluminium doors for your home or building project you will often be required to comply with certain performance values for energy efficiency. That is – you may be asked to select windows and doors with a specific Uw Value or Solar Heat Gain Co-efficient. In order to comply the window system must perform to the set parameters. It’s important to note, that these values are “whole window values”, not glass alone. These values are available for all AWS/Vantage aluminum windows and aluminium door products as part of their WERS rating.
The U-Value or Uw is a measure of conductivity of the whole window (glass and frame included). It is a number calculated to return an amount of energy flowing through the product at a given temperature difference per meter squared of window. The Uw is a number that indicates how well a window or door will retain heat in the winter and reject heat during summer. The lower the U-value the better the insulation properties of the aluminium window – the better it is at keeping the heat or cold out. In all cases regardless of climate zone an aluminium window with good insulation properties will help to improve the comfort of your home. To comply with energy reports U values must be Lower than or equal to that specified in the report.
ENERGY EFFICIENCY IN AUSTRALIAN BUILDING PRODUCTS
The SHGC or Solar Heat Gain Coefficient is a measure of the amount of heat that can be gained through your windows at times of direct solar contact. The SHGC is important as during summer the SHGC can add large amounts of unwanted heat to your house. Equally in winter the SHGC can be utilised to provide cost and pollution free heat from the sun. The Solar heat gain is measure as a coefficient and indicates the amount of direct solar heat that will penetrate your house.
The SHGC is mainly affected by the glazing type. Products like tinted glass and applied films can help to reduce the SHGC. It is important that when selecting windows and doors the orientation, location and house design are all considered to achieve the best outcomes. In cooler climates it is often advantageous to have a higher SHGC and in hotter climates a lower SHGC is better. To comply with energy reports, the SHGC must be within 10% of the set value