A study by the Queensland University of Technology (QUT) in Australia has found that roofs painted with a special reflective coating can decrease air conditioning use by up to 30% by reducing the amount of heat entering a building.
The two-year study, which took place in a sample of houses, schools, offices and retail spaces in Townsville and Brisbane, found that white roof coating reflected 88percent of the sun’s energy, Architecture & Design reported.
In contrast, standard roofs of a light colour reflect less than 65percent of solar energy, while dark roofs will reflect less than 25percent.
Researchers reported a 2°C drop in air temperature in rooms that weren’t air conditioned. The findings suggest that companies can save on energy costs by painting their roofs with the special coating rather than investing in expensive air conditioning units.
Professor John Bell, head of QUT’s School of Chemistry, Physics and Mechanical Engineering, said: “We saw average energy savings of between five and 30percent across the range of buildings, with most buildings showing savings above 15percent.
He continued: “It really is an extraordinarily simple solution. Twenty years ago it was cheaper and easier to put in an air conditioner than to paint your roof, but not anymore.
“Unlike air conditioners this is a passive cooling solution that does not require ongoing investment in the electricity network or in housing. Because of this, it would be a worthy candidate for inclusion in the building regulations much as they have done in the California energy code since 2005.”