White roofs a cool idea for city
- by: Anne Wright
- From: Herald Sun
- January 25, 2012 6:26AM
GIANT city developments like Costco will be urged to paint their roofs white, cutting indoor temperatures by up to 4C on hot days.
Certain types of building – particularly commercial low-rise with a large base area – could dramatically reduce the need for air conditioning, a University of Melbourne study found.
Lord Mayor Robert Doyle, speaking at the presentation of the research, said both existing and future developments such as Melbourne Airport and large retail developments should consider painting their roofs white.
“If they are large buildings but not high-rise then it’s going to have a huge effect,” he said.
“I think buildings will see that there is a financial benefit for doing it. This is not some feel-good exercise about sustainability in the environment, it happens to be an important element of it, but the economics are there.
“It’s modestly expensive to do, very short payback and then an immediate return on energy saving in the bills.”
Five test buildings with and without white coatings at the University of Melbourne’s Burnley campus were used for the study.
Lead author of the research Dr Dominique Hes said the study had monitored reflection of the white roof, the heat temperature of the roof and the internal temperature of the building.
The roof of the Artplay building at Birrarung Marr has also been painted white, but not as part of the study.
Dr Hes said painting a roof white reduced the external heat by about 30C, which was “the difference of being able to bake an egg”.
If a residential building roof were painted white it would reduce the heat in the roof cavity by 20 per cent, Dr Hes said, but because of building regulations for insulation there would be no reduction in the interior of the house.
Cr Doyle said commercial property developers could now look at ways to reduce energy consumption as well as waste and water in their sustainable designs.
Painting commercial buildings’ roofs white is popular in New York, he said, but hadn’t been picked up in Australia.
“I think it’s a chance for Melbourne to be a leader in Australia and show that you get real benefits from a very simple intervention,” he said.