Windows vital to energy efficiency

High performance windows and glass are critical to a building’s energy efficiency according to a report recently released by the Sustainable Windows Alliance.

High performance windows and glass are critical to a building’s energy efficiency according to a report recently released by the Sustainable Windows Alliance.

Following an18-month study on the impact of windows on residential energy efficiency, the report shows that a typical Australian home can achieve an increase of 2-2.5 stars of energy efficiency simply by changing from the worst-performing windows to the best-performing windows.

Typical homes in Australia use clear, single-glazed, aluminium framed windows. Australian Glass and Glazing Association Executive Director, Nigel Carpenter, says these ‘ordinary windows’ may have the advantage of being cheap to produce at low costs but they offer very poor thermal efficiency.

“With ordinary windows notorious for unwanted heat loss and heat gain, in most cases they will not be adequate for current home designs to meet increased building regulations,” says Nigel.

The study simulated over 4000 situations using various high performance window combinations, house sizes and orientations throughout 16 Australian climate zones. In the majority of cases the high performance windows significantly increased the building’s energy rating performance.

“The results clearly demonstrate the impact of glazing and framing options on building energy efficiency,” says Nigel. “Better performing windows significantly reduce energy consumption for home-owners, and therefore provide the opportunity for substantial savings on the household budget, and reduction in household carbon footprint.”

However the report also acknowledges there is no one window which will create an energy efficient home in all climates and house designs.

“No single window can claim to ‘make’ a house achieve 6-star. What works well in Cairns will not necessarily be suited to a home in Hobart,” says Nigel.

“Even in the same location, two different homes may require different windows to achieve the same star rating.”

The study is the first of its kind to take a nation-wide perspective focused on the impact of window performance on home energy efficiency.

The project is a joint initiative of the Australian Glass and Glazing Association and the Australian Window Association.

Read more on energy efficient windows.