Clean technology: The white roof project

By John Weekes

Photo / Getty
Photo / Getty

Ever walked barefoot across a black rooftop on a sunny day? After burning your feet or swearing like a sailor, you would have appreciated an insight Ian Montanjees had four years ago.

In 2008, the Mt Albert resident reflected on the big issues facing the planet, and wondered what difference he could make.

The challenges could seem overwhelming, even to a man with degrees in architectural studies and engineering. "I was thinking that global warming is the most significant issue facing our civilization in the coming years."

Montanjees, who jokingly called himself an "over-qualified handyman", saw promise in a simple solution.

As he thought about how polar ice caps reflected sunlight back into space and cooled the planet, a solution closer to home came to mind. With parallels in overseas initiatives, the White Roofs Project was conceived.

The colour that worked wonders on the rugby field didn't do New Zealand's cities, climate, or energy bills many favours. Concentrations of tarmac and dark roofs often made cities hotter than the surrounding countryside. But white, off-white, or cool-coloured roofs could be up to 35 degrees Celsius cooler than dark ones, helping to counter urban heat island effects. In large cities, such as New York, temperatures are always a few degrees warmer than the surrounding countryside.

White roofs also help businesses slash air-conditioning bills.

Officially launching the project in October 2010, Montanjees set up a website, spoke to business people, and tried to raise awareness with councils about white roofs. He had some breakthroughs. Resene set up a 30% discount for people wanting to paint their roofs in cool colours (available through a discount letter from Montanjees' website -

But Montanjees was working odd jobs to pay the bills while financing and pursuing his passion.

"Up to now, it's been voluntary and in my spare time. ?I funded it myself," Montanjees said.

He's now looking to get more people involved in the project's next stage, an 18-month White Roofs campaign. "So far I've got about half the sponsorship required to begin it. I need about six companies each putting in around $5000." Resene, Colorsteel and Metalcraft Roofing were on board, leaving space for at least three more sponsors.

Montanjees says a good target for the whitening of New Zealand roofs is about one third, as 75% of new commercial roofs built in the last 20 years are white already, but it is not yet a trend on houses. Studies show that 100 square metres of flat white roof cancels the global warming of roughly 10 tonnes of CO2 emissions. If one third of New Zealand roofs - approximately 200 million square metres - were made white or off white, then that would equate to taking up to 70,000 cars off the road for the 20-year lifetime of the paint, as well as reducing emissions from power generation through less air conditioning use.

Seen from space, the Blue Planet is looking whiter in a few more places. There's a reason those picture-perfect, whitewashed towns in Greece and Spain look the way they do. People in the Mediterranean realised long ago white roofs were cooler than dark ones. What is new is the realisation white roofs could help cool the entire planet.

In the U.S, white roof projects gained attention from Barack Obama's energy secretary, the Nobel Prize-winning physicist Steven Chu, who said power bill savings of 10 or 15 per cent were possible in buildings with white roofs. Chu decided all roofs on Energy Department buildings had to be either white or reflective.

The White Roof Project of New York told CNN painting 80 per cent of city roofs in the tropical and temperate climate zones would offset the carbon emissions of 300m cars, or 500 coal power plants.

The more roofs painted white, the bigger the impact. The Spanish province of Almeria is now on average 1.6 degrees cooler than surrounding regions, thanks to a massive expanse of white roofs on greenhouses.


Ian Montanjees says about three-quarters of commercial buildings built in Auckland since 1990 had white or off-white roofs. Montanjees says many businesses were interested in managing their heat loads, or doing their bit to fight climate change. He said companies that went for white roofs, such as Auckland Airport could wear their roof as a badge of honour.

To see a video presentation of Montanjees research, check out the video on our Clean Tech page.

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