Cool roofs
Home » Blog » Sophie Barclay » Cool roofsPolar icecaps keep the planet cool by reflecting sunlight back into outer space. By painting roofs white we can mimic this natural process, says Ian Montjeese.
Hasn’t the year gone quickly. I swear it was February last time I blinked. And now it’s mid-September, which means in less than four weeks it's time for one of the biggest events on the environmental calendar: 350’s Global Climate Working Bee. I remember last year on this day, I was on a plane flying from Dunedin to Wellington which made me feel decidedly guilty. This year I have vowed to be different.
Photo by Muffet via Flickr
First stop was the website to see what activities are happening on the 10 September 2010. One in particular caught my eye. Initially, I was struck by its simplicity. It does seem a bit of a no-brainer and I wondered why no one had thought of it before.
Here’s the gist: one man has decided to take on global warming by trying to encourage people to paint their roofs white.
Ian Montjeese, an inventor-come-physicist with degrees in engineering and architecture, is trying to spread the word about white roofs. He’s in good company. US Secretary of Energy, Dr Stephen Chu, has been trying to implement similar measures across the States this year.
New research shows that by painting the roofs of buildings white or light coloured instead of Baked Earth, Beaten Track, Black Magic, Brownie Points or Birthday Suit, we can halt global warming.
If 50 percent of the roofs in New Zealand were painted white, this would have a cooling effect that would cancel the global warming produced by New Zealand's vehicles, permanently.
Ian has done calculations of his own and says: "If 50 percent of the roofs in New Zealand (roughly 18,000 football fields) were painted white (or pale coloured) this would have a cooling effect that would cancel the global warming produced by New Zealand's vehicles, permanently."
Ian had the idea three years ago and tried to contact government departments who didn’t really take the idea seriously. However this year he plans to get his paintbrushes out and start making a difference.
“I was thinking about how I could make a really significant condition to global warming, not just some little thing like turning the kettle off at the wall or putting the exact amount of water in. Something huge. And it just came to me about how the polar ice caps reflect sunlight back into space and how we could mimic that, and I did some
calculations and they all stacked up."
This is just the beginning—the white idea can be applied to roads, pavements and car exteriors, just to name a few.
The basic physics
Photo by darren_ck via Flickr
When a roof is white, or an object is white, it reflects light. When sunlight is reflected off a white roof, about 60 percent is reflected (depending on when you last gave it a good wash) and most of this goes back into space. When a roof is black, brown or dark coloured, it gets converted to infrared wavelengths, which then get stuck in the blanket
of greenhouse gases that warms the earth. This is a
natural phenomenon, but humans are adding too much greenhouse gas to the ‘blanket’, which is going to make this planet a scary place to live unless we do something to cool it.
If you aren’t sold yet, white roofs can also keep your air
conditioning costs down! Due to the cooling effect of the white roof, it can lower the price of cooling a building by 10–15 percent!
If white just isn’t your thing, don’t worry, there are also a whole host of cool-coloured paints available and paints with high reflectivity from places like Resene. But if you’re keen to reduce global warming—rather than wanting to keep your roof a handsome chocolate brown—then Ian insists white is definitely the colour to go for. It has a reflectivity of 60 percent compared with 28 percent of cool colours.
So, where do I sign, I hear you asking. Sign up on 350.org.nz or for more information on Ian’s idea, or to donate so he can get this thing started, contact him directly: Ian.Montanjees@whiteroofs.org.nz.
blinked. And now it’s NEARLY the tenth of September which means that
in just 4 weeks it is time for one of the biggest events on the
environmental calendar; 350’s Global Climate Working Bee. I remember
that last year on the day in question, I was on a plane flying from
Dunedin to Wellington which made me feel decidedly guilty. This year I
have vowed to be different.
First stop was the website (http://www.350.org.nz/) to see what
activities are happening on the 10/10/10. And one in particular caught
my eye.
Initially, I was struck by its simplicity. It does seem a bit of a
no-brainer, and I wondered why no one had thought of it before. Here’s
the gist: one man has decided to take on global warming by trying to
encourage people to paint their roofs white.
Ian Montjeese, an inventor-come-physicist with degrees in Engineering
and Architecture is trying to spread the word about white roofs
http://www.350.org/white-roofs-project-nz. He’s in good company. US
Secretary of Energy, Dr Stephen Chu, has been trying to implement
similar measures across the States this year
http://www.youtube.com/watch?v=5wDIkKroOUQ.
New research shows that by painting the roofs of buildings white or
light coloured instead of “Baked Earth, Beaten Track, Black Magic,
Brownie Points or Birthday Suit”, we can halt global warming (see
http://www.energy.ca.gov/2008publications/CEC-999-2008-020/CEC-999-2008-020.PDF).
Ian has done some calculations of his own and says that “if 50% of the
roofs in New Zealand (roughly 18,000 football fields) were painted
white (or pale coloured), this would have a cooling effect that would
cancel the global warming produced by New Zealand's vehicles,
permanently.”
Ian came up with the idea three years ago and tried to contact
government departments who didn’t really take the idea seriously,
however this year he plans to get his paintbrushes out and start
making a difference
“ I was thinking about how I could make a really significant condition
to global warming, not just some little thing like turning the kettle
off at the wall or putting the exact amount of water in. something
huge. And it just came to me about how the polar ice caps reflect
sunlight back into space and how we could mimic that, and I did some
calculations and they all stacked up”. This is just the beginning –
the white idea can be applied to roads, pavements and car exteriors,
just to name a few.
The basic physics -
Don’t worry if you don’t have a PhD in physics. I don’t either. I wish
I did, it would mean that was slightly more employable, but that’s
another story.
When a roof is white, or an object is white, it reflects light. When
sunlight is reflected off a white roof, about 60% is reflected
(depending on when you last gave it a good wash) and most of this goes
back into space. When a roof is black, brown or dark coloured, it gets
converted to infrared wavelengths, which then get stuck in the blanket
of greenhouse gases that warms the earth (which – by the way – is a
natural phenomenon, we are just adding too many of these greenhouse
gases to the ‘blanket’ which is going to make this planet a scary
place to live).
And if you aren’t sold yet, white roofs can also keep your air
conditioning costs down! (is there anything they don’t do?) Due to the
cooling effect of the white roof, it can lower the price of cooling a
building by 10-15%!
White just isn’t your thing? Don’t worry, there are also a whole host
of cool coloured paints available and paints with high reflectivity
from places like Resene (http://www.resene.co.nz/pdf/CoolColour.pdf).
But if you’re in this for the reducing-global-warming capability
rather than the
wanting-to-keep-my-roof-a-handome-chocolate-brown-but-be-climate-friednly
kind of way Ian insists that white is definitely the colour to go for
(it has a reflectivity of ~%60 compared with %28 of ‘cool colours’).
So, where do I sign?, I hear you asking. Sign UP on 350.org.nz or for
more information on Ian’s idea, or to donate so he can get this thing
started, contact him directly (Ian.Montanjees@whiteroofs.org.nz).
For more information on cool roofs try here:
http://en.wikipedia.org/wiki/Cool_roof
Fri September 17, 2010 @ 06:58 PM
