AIBS National News

Recent years have seen major advances in the Australian glass industry, and the result is a wide range of glass solutions available to maximise control over thermal comfort and energy efficiency in homes throughout the country.

With homes subject to increasingly stringent star ratings – the BCA 2010 will produce a minimum 6 star rating for new homes and renovations effective from May 2011 – perhaps one of the most significant characteristic of glass is its ability to dramatically reduce the amount of artificial heating and cooling used by homes. Using suitably glazed windows is one of the easiest ways to gain more control over a home’s thermal comfort. This is backed up by a Queensland University of Technology (QUT) study, which found that improved glazing choices can increase a home’s star rating by 1.5 to 2.5 stars. Viewed in a different way, if all Australian homes were fitted with high performance glazing, greenhouse gas emissions would be reduced by approximately 8 million tons per annum, which is the equivalent of taking 1.6 million cars off the road.

This is not surprising when you consider that windows with standard single pane 3mm flat glass are generally the thermal “weakest link” in residential buildings. Few people know that up to 87% of heat gain and up to 49% of heat loss occurs through unsuitably glazed windows. This means that homes with ordinary windows are using up to an incredible 60% more energy to heat and cool their home than necessary. Energy efficient glazing can significantly reduce the amount of heat that travels through windows, improving thermal comfort and saving homeowners money at the same time. There are many energy efficient glazing solutions available, all of which can be achieved without heavy tinting or mirror like coatings that can detract from a home’s appearance.

Low E (low emissivity) glass can reduce the amount of heat that is conducted through the glass by around 30% compared to ordinary glass and reduce the need for air-conditioning and heating, however the most comprehensive solution is found by combining a Low E coating with double glazing.

Double glazed units (also known as Insulated Glass Units or IGUs), comprise two or more panes of glass separated by an air (or gas) filled cavity, providing improved thermal insulation. When combined with a Low E coating and suitable frame, this option can stop up to 70% of heat loss and 77% of heat gain when compared to standard 3mm glazing.

“The ideal insulating glass choice allows occupants to forget about monitoring their home’s energy performance and focus on enjoying the increased comfort of their indoor environment,” says Nigel Carpenter, AGGA’s Executive Director. “People don’t often realise it, but ordinary glass in windows is old technology – there’s a wide range of performance glass available that has so much more to offer than the 3mm clear window glass we all grew up with.”

We only have to look back over the last couple of decades to see just how far the glass industry has progressed; these days it can fulfil virtually any requirement imaginable. Keen to cut back air conditioning and heating costs? Check. Want to block the distracting sounds of traffic outside a home? Need to maximise security and ensure a building can withstand threats such as cyclonic winds and bushfires? Check. All of this can be achieved without heavy tinting or mirror like coatings that reduce natural light and detract from the appearance of a home’s appearance.