Habitat 15 - White out

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Habitat 15 - White out

Embracing eco-friendly principles can seem tricky if it is complicated or costly. Now there's a measure that's simple but effective. It's painting your roof white, and usually involves no extra cost during regular maintenance.

The idea is slowly catching on as one of the fastest and cheapest ways to help reduce global warming by mimicking the way that the polar icecaps reflect sunlight back into space and cool the planet. Buildings without air conditioning also benefit by being cooler and more pleasant to inhabit in summer, according to local campaigner Ian Montanjees. Those with air conditioners use less electricity.

When sunlight falls on a white roof, much if it is reflected back into space, whereas when sunlight falls on a dark roof, much of it is absorbed and converted into heat. This heat is blocked from passing back into space because it is absorbed by greenhouse gases in the atmosphere.

Says Ian: 'The White Roofs Project is an immediate action plan that people can do themselves or that can be organised on a national level, as a win-win solution. While many people have a feeling of helplessness about what they can personally do about reducing global warming, when they see people, business, and governments being slow to take the necessary steps, the white roofs idea gives us a positive action plan that we can do ourselves without having to wait for others to act.'

Scientific research has shown that a flat white roof measuring 100 sq m (the size of a modest house) reflects enough sunlight to cancel the global warming of about 10 tonnes of carbon dioxide emissions (roughly that put out by 2.5 cars over one year).

Ian isn't alone in his passion for white roofs. The US Secretary of Energy Dr Steven Chu, a Nobel Prize winning physicist, is a supporter and the Obama administration is now painting federal roofs white (in America, the movement is called 'cool roof'). The Mayor of New York's cool roofs campaign has passed the one millionth square foot of white roof and attracted partnerships with local well-known businesses. There is now a Cool Roofs Project co-financed by the European Union in countries like the UK, Greece, Italy, and France.

White roofs have been used here not just on houses but also on large buildings like the Sylvia Park Shopping Centre in Auckland. The off-white Auckland International Airport roof is another well-known example. www.whiteroofs.org.nz.

When white's not alright
A white roof won't be suitable for every home. If your roof is overlooked by a neighbour who might find a white roof too bright, then use a deeper tint of off-white or consider a darker colour using Resene Summit Roof CoolColour paint.

When town planning regulations in some areas only allow for dark roof colours that blend in with the bush, darker shades of Resene CoolColour paint offer a valuable alternative.

While this paint is not as reflective as pure white paint, it is significantly more reflective than standard paint of the same colour due to special pigments that reflect more of the sun's energy, keeping your roof cooler.

A Resene CoolColour option is also ideal if you want to improve the amount of heat your roof reflects but don’t like the thought of having a pure white roof as part of your exterior colour scheme.

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