Keeping your home cool in summer and warm in winter at a reasonable cost is becoming more practical with the ready availability of a broad range of modern building materials. Modern homes and home extensions often include large areas of glazing which can have a major impact on the energy efficiency of your home. Poorly designed windows, skylights and glazed doors can make your home too hot or too cold. If designed correctly, they will help maintain year-round comfort, reducing or eliminating the need for artificial heating and cooling. Choosing the right 'performance glazing' (energy efficient glass) lets you control how much heat enters or escapes from a building, is critical to a building’s energy efficiency and can significantly influence whether you achieve the standards required by increasingly stringent building regulations.
Insulated glass units (IGU’s) or double glazed units are a significantly more energy efficient glazing system than single glazing. IGU’s consist of two or more layers of glass separated by a void normally filled by air or inert gases such as Argon. The combination of airspace and glass panes act as an additional barrier, making the transfer of heat by convection, conduction and radiation more difficult. The glass panels are separated using aluminium or other types of spacers around the edges, hermetically sealed to the perimeter in controlled conditions. Common spacers range in width from 6 mm up to 14 mm. The spacer contains a desiccant (drying agent) which eliminates moisture vapour in the cavity.
You should be aware however, that they are not the total solution. You also need to take into account the climatic conditions in your location, shading, size and location of other glazed surfaces (windows and skylights) and also make sure these components are properly installed and sealed to minimise unwanted draughts.
The key features of insulated glass units are:
Solar and thermal control;
Reduction of heat build up in summer;
Reduction of winter heat loss and condensation;
Lower air conditioning and heating energy costs;
Improved occupant comfort, particularly next to windows by reducing hot and cold spots;
Lower noise penetration;
Lower UV transmission;
Increased wind-load strength;
Our high performance Argon and air filled Insulating Glazing Units (IGU's) feature 4 or 5 mm tempered (toughened) glass and a low emissivity (Low-e) coating that allows transmittance of visible light but provides excellent insulating properties.
The key measures of energy performance that relate to fenestration products are Solar Heat Gain Coefficient (SHGC), U Value and Visible Light Transmission. These three measures are of great importance when considering the design of a building to ensure comfort and energy performance.
|Product||Colour||Visible Light Transmittance||U Value (W/m2.C) Summer||SHGC|
|5 mm Clear Tempered Low-e+ |
6 mm Argon filled gap +
5 mm Clear Tempered
|3 mm Clear||Clear||83%||6.25||0.86|
|This Solar and optical data is based on the National Fenestration Rating Council measurement standard and relates to the IGU unit not the door assembly.|
The installed doors will provide energy savings but the performance will only be as good as the weakest component. Installing highly energy efficient Double Glazed Doors will be significantly impaired if appropriate seals are also not installed. Talk to your door supplier / builder or find a suitable product from Australia's leading supplier of Door and Window Sealing Systems.