Comments on: Steve Chu’s White Revolution

By: Jaime Silas

Jaime Silas — Wed, 10 Mar 2010 17:56:32 +0000

Something that really helps me is my huge tree’s…. keeps my house cool. So lots of trees would probably help the g-warming too…. I just made that discover and should be a nobel prize winner

- Jaime
Omaha HVAC

By: Cory Suter, GRP

Cory Suter, GRP — Thu, 25 Feb 2010 20:28:23 +0000

One important dynamic about cool roofing that most people miss, is that cool roofs last significantly longer due to less extreme changes in temperature. The worst thing for a roof is for it to heat up over a hundred degrees in the winter sun, and then drop below freezing at night. This expansion and contraction causes the roof to crack and need replaced more often than a cool roof, which maintains a more consistent temperature. Black roofs can heat up over 180 degrees in direct sunlight in the summer. When it comes to losing beneficial heat gain in the winter, the truth is that in most climates North American climates the reduced cooling costs in summer far outweigh the savings in heating costs. This is because the sun is less direct and less intense in the wintertime; also the sun is more likely to be hidden behind clouds. Personally, I have a cool roof to save on roofing expenses and thick attic insulation to save on heating and cooling expenses. Again, reach out to me at http://www.bioneighbors.com, if you want to learn more.

By: Cory Suter, GRP

Cory Suter, GRP — Thu, 25 Feb 2010 20:17:27 +0000

I have been coating roofs white in Philadelphia for four years now; and have achieved some impressive results in lowering my customer’s air conditioning expenses – savings for some of over $100/month in the heat of the summer, using roof coatings that are guaranteed by the manufacturer for ten years. At the same time, I’ve learned from mistakes. Professional Roof Coatings may last a long time, and some of the better ones get cleaned by the rain naturally, they are not, however meant for shingled roofs. Last summer, I ruined a client’s suburban shingled roof by coating it. The coating trapped moisture under the shingles causing leaks to develop at many of the nail locations. I have information on http://www.bioneighbors.com about my experiences, and am happy to answer questions that my website does not address.

Lets work together to create smart solutions, so our grandchildren can live even better than we did!

By: Andrew Maynard

Andrew Maynard — Wed, 23 Sep 2009 08:33:53 +0000

True, we don’t have the benefit of the sun heating the shingles in the winter. But the rate of radiative heat loss from the roof is lower than if it was darker, and the paint is also an insulator, so things aren’t too bad. And I must admit that the comfort levels achievable in the summer inside the house, now we have the white roof, far outweigh any small disadvantages in the winter!

By: Randy in Richmond

Randy in Richmond — Wed, 23 Sep 2009 01:27:48 +0000

I live in Virginia. What you gain in the summer will be lost in the winter.

By: Geoengineering the climate: A clear perspective from The Royal Society

Geoengineering the climate: A clear perspective from The Royal Society — Tue, 01 Sep 2009 11:23:21 +0000

[...] the recently-publicized approach of painting roofs white (and other urban surface albedo raising ideas) doesn’t fare too well in this assessment. [...]

By: tony

tony — Tue, 11 Aug 2009 00:10:26 +0000

So why don’t we put mirror on top of the roof? If this suggestion is accepted, I’m gonna open a mirror roof company.

By: Andrew Maynard

Andrew Maynard — Fri, 07 Aug 2009 12:56:22 +0000

Thanks Thassanee.

For those interested, there’s more information on this initiative at http://www.onedegreeless.org

By: Thassanee Wanick

Thassanee Wanick — Fri, 07 Aug 2009 04:14:36 +0000

I painted my roof white using 5 cans ( 18 L – at US$70 each) of Sherwin Williams self cleaning , water based ECO Metalatex paint. I used WAP pressurized water to clean the roofs (RED CEMENT) first then after it is dry , I painetd.
It took a week to paint 333 sq, but I have thus, offsets 33 tons of Carbon.
My house looks taller and beautiful and the neighbors came to look and are painting theirs too!
Then I convinced the Mayor of the city to paint the roofs of 2 schools and he even committed to 16 more schools.
Then it caught on and we painted hospital’s roof white.

At the International Rolex Sailing Week, we painted the Yacht Club’s roof.

Now the government in Brazil had committed to me to deliver, in the next 3 months 35,000 low income houses – 1/3 roof area will have solar panels for heating water, and 2/3 of the roofs areas are being painted white.
They are also thinking of painting 180,000 homes all white as well!

I cannot paint the world alone. Please help?
If we all get up and help a little we might have the hope to solve Global Warming effects just like we did with Ozone hole; which by 2009 is only slightly below normal .

Please post your pictures on our website and we will send you the logo/certification
One Degree Less – White Roof Campaign (Global Cooling Initiatives).

I , the Polar bears and the children who still sleep in the street in the hurricane affected areas thank you!

http://www.youtube.com/watch?v=b0r1PzgleXw

By: 1. White Roofs « 101 Ways to Change the World Along 101

1. White Roofs « 101 Ways to Change the World Along 101 — Fri, 31 Jul 2009 18:53:41 +0000

[...] For more information take a look at these links: Steven Chu’s White Revolution [...]

By: 98. White Roofs « 101 Ways to Change the World Along 101

98. White Roofs « 101 Ways to Change the World Along 101 — Tue, 28 Jul 2009 08:54:27 +0000

[...] For more information take a look at these links: Steven Chu’s White Revolution [...]

By: Worst Case Scenario - Likely Scenario » Blog Archive » Untitled

Worst Case Scenario - Likely Scenario » Blog Archive » Untitled — Fri, 26 Jun 2009 23:41:51 +0000

[...] work at the Los Alamos National Laboratory toward developing technology to fight global warming to painting rooftops and roads around the country white to increase the Earth’s albedo and save energy. This is a sea change [...]

By: Herb Lin

Herb Lin — Thu, 18 Jun 2009 15:26:23 +0000

So how did you choose the particular product you used? (Hy-Tec Thermal Solutions Insul Cool-Coat white paint)
And did it matter to you that it was not on the DOE Energy Star list (http://www.energystar.gov/index.cfm?c=roof_prods.pr_roof_products)?

thanks herb

By: Andrew Maynard

Andrew Maynard — Mon, 15 Jun 2009 11:26:02 +0000

Go for it I’m still amazed at the difference the white roof makes in Summer. There are days (before the high humidity sets in) where I’m enjoying open windows and cool breezes while all around I can hear neighbors’ AC units humming.

By: Greg Butler

Greg Butler — Mon, 15 Jun 2009 11:12:09 +0000

I was thinking along those very lines before I go out of bed this morning. And then to see this article was a wonderful synchronicity.

By: Andrew Maynard

Andrew Maynard — Thu, 28 May 2009 11:03:49 +0000

Only when I think I might be seen

By: Andrew Maynard

Andrew Maynard — Thu, 28 May 2009 11:02:57 +0000

Thanks for the study link Mike – extremely useful (~10 m square white roof estimated to offset 1 ton CO2 emitted)

There definitely are options for IR-transparent, UV-opaque coatings – using nanoscale TiO2 particles for instance should be able to provide an appropriate transmission window. But you obviously loose out on the thermal conversion that would result in absorbing the UV as well.

And realistically, the difficulties of “retrofitting” white roofs are substantial – love the macabre image of the Sunday morning DIY-ers

By: Mike Todd

Mike Todd — Thu, 28 May 2009 09:28:33 +0000

Here is a link to the study report presentation that regenerated interest in this idea. http://bit.ly/Wd15b.

Since I live in the cold (but getting warmer) UK, I was wondering whether there is something that looks black or transparent in the visible, but reflects UV. A quick Google search showed that there were coatings that claim to do this for textiles e.g. coldblack®: Sun Reflector – UV Protector (http://bit.ly/y49B0). However this approach, or the white paint approach, would be a difficult sell where there is no air-con energy costs to recover. Also I can imagine Sunday morning scream-thuds of DIY-ers falling from their pitched roofs!

By: Rob Aitken

Rob Aitken — Thu, 28 May 2009 08:16:10 +0000

Ahead of the curve as always Andrew! Of course, not relevant in Scotland as we’re still huddling together to keep warm even in the ..ahem.. height of summer. Love your portayal as a british eccentric. Do you also wear a smoking jacket around the house?

By: Andrew Maynard

Andrew Maynard — Thu, 28 May 2009 00:12:09 +0000

The white pigment in paint like the stuff I use is a broad band reflector – reflecting everything from infrared through visible light to UV. Reflecting the infrared reduces heating – the primary aim of the exercise, and what should in principle lead to lower cooling bills. But it is the UV that is reflected that could help combat global warming – assuming enough surfaces were coated.

By: Andrew Maynard

Andrew Maynard — Thu, 28 May 2009 00:08:39 +0000

Unfortunately, replacing the HVAC and fluctuating fuel costs prevented a before and after heating/cooling cost comparison. It seems reasonably sure that cooling costs are lower that they would otherwise be, but I’m not sure about the heating. Interestingly, I had heard that before widespread air conditioning was available, white roofs were more common as a way of preventing heating in the summer – and the move to darker shingles is on aesthetic grounds (and perhaps cost, although that’s speculation). But I have no proof for this.

The lack of solar heating in the winter is something that concerned me, although I’m not sure how significant solar radiation heating via dark shingles is. However, having a white roof should in principle reduce radiative heat losses from the house.

Clearly though, the perfect solution would be paint that can change color at the flick of a switch – white in summer, black in winter! Now where have I seen something like that… e-ink! E-ink consists of microcapsules of white and black pigment – applying an electrical pulse simply switches which pigment is visible.

So here’s an idea – paint roofs with e-ink, then simply switch from light to dark with the changing seasons. You could even have embedded messages for high days and holidays

By: William Sharkey

William Sharkey — Thu, 28 May 2009 00:06:42 +0000

Can you please talk about infrared light? Do you know if it is significant to a project like yours?

By: Ruth Seeley

Ruth Seeley — Wed, 27 May 2009 23:54:38 +0000

Have you done an overall comparison of heating and cooling costs though? Surely the dark roofs weren’t just an aesthetic consideration, but were designed to attract heat in the dead of winter? And if you’re spending more to heat your home now that the roof’s white and you’re using fossil fuels to heat it….well, you see where I’m going with that.

I think it looks nice, actually.

By: Andrew Maynard

Andrew Maynard — Wed, 27 May 2009 23:33:56 +0000

Three yearly repaints – you’ll be lucky! The durability question did worry me – seems to have weathered 12 months OK, but I’m hoping for another 24 at least before I have to do the roof-walking stuff again.

By: Tim Jones

Tim Jones — Wed, 27 May 2009 22:32:17 +0000

Very cool ! (pun intended). And Christmas all year round. Guess you’re looking at what – 3 yearly repaints? The eccentric minority often leads the way – and is usually ‘right’