Cool roofs: creating cooler, more sustainable communities
People who drive past Stockland’s Aura development in Queensland often ask why the houses have light coloured roofs, and the answer is that they make a proven contribution to both the sustainability and liveability of a community.
Analysis by the University of NSW has found that the light coloured or ‘cool’ roofs reduce temperatures by around two degrees compared with houses in surrounding suburbs, and deliver potential energy savings of up to 40%. They can also reduce heat-related mortality by as much as 30%, according to UNSW researchers.
A cool roof policy has been implemented at Aura to reduce what is the called the Urban Heat Island Effect, which occurs when urban areas replace natural land cover with pavements, roads and buildings which absorb and retain heat.
To measure the real-life impact of Aura’s cool roof policy, Stockland partnered with Urbis to compare the temperatures within Aura with a nearby community which had not implemented a cool roof policy.
The study found that Aura was 1.5 - 2 degrees cooler than this comparative community and that temperature reductions would be expected to be even greater with the adoption of other heat island mitigation measures such as increased tree coverage or blonde asphalt.
Sophie Lam, Associate Director at Urbis, said that the research was also a valuable source of information for their own internal database.
“It's fascinating to see how the implementation of cool roofs has made a significant difference in temperature. We're really excited to explore the possibility of what could be achieved with the integration of cool pavements, urban greening and other practical mitigation measures,” she said.
Stockland’s Senior Environment and Community Development Manager, Mark Stephens, explains the cool roof policy requires all the homes at Aura to have roofs which meet specific solar absorbency standards.
“Light coloured roofs do a great job of reflecting heat, making the homes cooler and more energy efficient,” says Mark.
“This results in less heating and cooling requirements which also has the added benefit of reducing energy bills for residents.
“With heat being reflected away, the entire community then becomes a cooler community, increasing comfort levels for residents walking or riding through the numerous parks and streetscapes,” he says.
Nestled in the shadows of the Glasshouse Mountains and close to the heart of the dynamic Sunshine Coast region at Caloundra, Aura is Australia’s largest residential development project, ultimately comprising 20,000 homes spanning 2310 hectares.
With sustainability a critical commitment at Stockland, the development at Aura is leading the way.
“We knew we had to approach Aura differently as a master planned community as it sits within one of the most sensitive receiving environments with the internationally protected Pumicestone Passage located only a few kilometres downstream,” said Mark.
“Aura has adopted best practice construction and water sensitive urban design measures to enable water quality discharge at the highest standards.”
More than 30% of the Aura site will be green space and over two million trees will be planed, while over 700 hectares will be rehabilitated including a dedicated Environmental Protection Zone.
Following on from the initial study, Urbis is now working with Stockland to prepare an Urban Heat Island Mitigation Guideline, which will be a simple document outlining the key mitigation measure categories which can be immediately implemented into new communities such as urban greening, cool roofs and cool pavements.