After reports of record-breaking heat in the last year alone, and with another heat-wave about to hit southern Australian states this week, the Association of Building Sustainability Assessors (ABSA) has highlighted five simple energy efficient and sustainable steps for cool homes this summer.
According to Sid Thoo, ABSA’s chairman, “heating and cooling accounts for around 38% of household energy use and 20% of carbon emissions from a typical Australian home”.
ABSA highlights the importance of knowing which direction the sun is coming from as it can stop unwanted summer heat entering the home. Generally, windows facing toward the north in your main living areas not only provide plenty of natural daylight but also keep out direct sun in your living space.
An ABSA key tip is allowing the roof to overhand the external walls by around 500-600mm to ensure direct sun is kept to a minimum and stop your house from overheating.
As well as knowing where the sun is coming from, the ABSA says choosing light reflective colours for external surfaces – especially the roof – will help reflect solar radiation. As apposed to a house with darker colours, which absorb more solar radiation, a house with lighter colours means that the air conditioning has to work 20% less on average.
Another tip is avoiding bare metal finishes such as galvanized roofs which although reflect a lot of visible light don’t necessarily reflect as much infrared radiation from the sun – which is what causes your house to heat up.
Insulation not only keeps the house cool in the summer and warm in the winter, but having the right amount of ceiling and roof insulation in place is a key factor in keeping your house cool. Bulk insulation such as fibreglass batts, and blow-in newspaper is best for the ceiling, while reflective insulation such as building foil and sarking, works best on the underside of the roof covering, says ABSA.
Most of our capital cities are located near the coast, where the difference in temperature between the land and sea often creates cooling afternoon breezes to blow in from the coast. Placing doors and windows in the right places allows you to take advantage of natural cooling. The type of window opening also makes a big difference – casement and sliding windows provide more ventilation than awning windows.
ABSA also recommends taking advantage home assessments by a qualified Nationwide House Energy Rating Scheme (NatHERS) assessor before finalising your home design. Specially trained NatHERS Assessors can simulate the thermal performance and help make decisions before plans get locked-in. Simple design considerations that add little or no cost to your building will reduce the need for artificial heating and cooling.
The ABSA stresses that most new houses in Australia have to meet a minimum six out of ten star energy rating and thus by getting an experienced Assessor to provide advice in the early stages of design for your new home, you can achieve even higher star ratings without adding considerably to the cost of the build.
Rodger Hills, ABSA’s CEO, stresses that “with what we now know about the effects of a changing climate, it’s vital we improve our housing stock and future-proof it against rising energy demand and costs – the design and construction of energy efficient housing is critical for all Australians”.
