This links to an amazing discovery in a Townsville community pilot project in 2011. After their roofs were painted white, residents in the pilot program felt their homes were cooler and more comfortable even with less air conditioning.

The energy bill shrunk notably leaving them to wonder how that happened! One home in Townsville reduced its average electricity demand by 57%, with an average across the participating homes of just over 30%.

Some of the residents reflected on white roofs and said: ‘we don’t use air-conditioning as much as we don’t need it as much and it impacts our electricity bill’; and ‘Already told several work colleagues – main interest is from the lower power bill’.

Townsvillians have uncovered a local living style unique to the tropics!

Getting free cooling from your roof, rather than paying for costly air conditioning makes good sense. With its high incidence of solar radiation and high year-round temperatures Townsville is the ideal location for white roofs.

White paint can reflect as much as 80 – 98% of the sun’s heat away compared to red or green paint which reflects around 45%, galvanised steel that reflects around 35%, or dark paint which only reflects 5 – 10%.

In technical terms these two processes are called the ‘Solar Reflectance’ (also known as the ‘Albedo Effect’) and the ‘Thermal Emittance’. Both of these characteristics are important so look for the white paint with the highest solar reflectance and thermal emittance percentages (sometimes shown on a scale of 0 – 1).

Countries around the world are now requiring a minimum solar reflectance of between 65 and 78%, and a minimum thermal emittance of between 70 and 85%.