A low-tech tool to counter the sun’s effect on global warming
July 1, 2009 by Tom GuayPosted in: Cost Cutting, In this week's e-newsletter, Latest News & Views, News, Technology
Not every green improvement has to be a fancy, high-tech, technological breakthrough. One of the more potent ways to battle global warming is a decidedly low-tech solution: White paint.
Repainting a roof white can deflect 75% of the sun’s light back into the atmosphere, thus reducing the impact of global warming attributed to the sun.
And, with all that heat bouncing off the roof, a business can dramatically reduce its air conditioning bill, which then helps reduce the other cause of climate change: greenhouse gas (GHG) emissions.
It’s a strategy that Steven Chu, Secretary of the Department of Energy (DOE), started promoting as something simple and relatively easy to do.
The Washington Post reports that research at Chu’s former employer, the Lawrence Berkeley National Laboratory, predicts that painting 63% of roofs white in 100 cities in the world’s temperate and tropical areas would have the same global warming reduction impact as removing all cars off the road for 10 years. The Post story is here.
Chu says DOE will explore ways to encourage more white roofs on private and public buildings in the U.S.
But the white roof idea’s not just a math exercise. California already requires flat roofs to be white and Wal Mart has white roofs on 75% of its stores.
Smaller buildings are also adopting the white roof idea. In Tallahassee, FL, a new FSU Credit Union branch will include a white roof. The building will qualify for a silver rating under the U.S. Green Building Council’s Leadership in Energy and Environmental Design program.
Builder Culpepper Construction Co., Inc. says the white roof will cut the sun’s heat effect in half and reduced the size of the bank’s air conditioning system.
Click here for FSU’s story.
Tags: CO2, GHGs, global warming, LEED
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July 2nd, 2009 at 2:08 pm
What a bunch of BS. Doesn’t anyone realize that the total developed area of the US is about 5% of the land mass? This is just another scheme of the enviro-whackos to make us all feel guilty about everything we do. I’m sick of hearing about “green” and “carbon footprint,” etc. It’s all anti-capitalist, anti-free trade measures to harm the productivity in the US.
July 2nd, 2009 at 2:31 pm
Well said LEU. Will there be paint companies rushing to develop “enviro-friendly asphalt shingle paint”? This reminds me of the people who gave up their refridgerators to “go-green”, yet they still bought ice and resorted to purchasing smaller quantities of items resulting in greater packaging waste and more trips to the store. All this is such nonsense!
July 2nd, 2009 at 2:39 pm
LEU, the developed area of the US may only comprise 5% of the land mass, but that 5% accounts for pretty much 100% of the air-conditioners used, and if we can cut the amount of electricity used in all those buildings dramatically by doing so, then you would see a significant reduction in carbon emmissions all around. Not so shabby.
July 2nd, 2009 at 2:58 pm
While it may be possible to reduce heat on the surface of buildings wtih white roofs, it is not practicle to install white shingles in most cases. I would not pay to have shingles painted and I would not replace a roof before its time just to get white shingles. I have however seen white shingles that by far have outlasted other colors.
But what about this. Dark shingles provide more heat inside an attic in the winter thus helping to reduce the cost of heat in a house, and related fuel to heat the home. Most of the heat in a home is lost either through the windows and doors or the attic. I think a better use of roofs would be to move the heat from the heated attic in the winter into the home or garage somehow. The cost of a fan, thermostat and ducting is much cheaper than an installed furnace and allowing the heat to escape into the atmosphere. Even closable attic vents might help capture this lost solar heat.
July 3rd, 2009 at 8:07 am
I think the article is a bit off the mark. It doesn’t follow that reflected sunlight on its own don’t do much (if anything) to help reduce climate change. The savings is from not absorbing the heat and then having to crank the aid conditioning. I live in Vermont, a little absorption of heat is good for most of the year. Air conditioning is not used so much; but, I’m sure there are those business (grocery stores for instance) that could use this idea.
It’s really pathetic to hear whiners like LSU and Boozer who obviously don’t have a grasp on physics or the economy. They want to rail against the green movement because they have been the ones fighting against it for years. If we made changes to our lifestyles and wized up decades ago, we’d be better fiscally and environmentally. Good example- gas guzzler SUVs from detroit were a stupid mistake. They ignored environmentalists and now they’re bankrupt. By the way, what has free trade capitalism brought us? The chickens are home to roost- Bush/Cheney and anti-regulation, along with anti-green policies have bankrupt this country and put the US in the back seat to the future. Our own stubborn ignorance is going to keep us economically behind the rest of the world as they embrace green technology and we find ourselves being brought along kicking and screaming.
By the way, what the heck is Bozo talking about when he says that people gave up their fridge? More anti-green propaganda from the scared right who now realizes they are on their way out.
July 6th, 2009 at 8:04 am
If any of you whiners read the full article, you’d see it says its a “simple and relatively easy to do” and focuses on businesses/commercial use. This isn’t the government trying to make everyone put a white roof on your shingled roof, (even though the benefits of this reflective color have been well proven for years). “A business can dramatically reduce its air conditioning bill, which then helps reduce the other cause of climate change: greenhouse gas (GHG) emissions”. Businesses use large conditioning systems because they are large buildings with large roofs. A white roof would help, it’s not that hard to imagine. It also says “the DOE will explore ways to encourage more white roofs on private and public buildings in the U.S.” This is not a solution to the global warming problem, just a small suggestion to help. Relax.
July 7th, 2009 at 1:52 pm
We had the flat roof on our facility replaced last year. Instead of the black roof we had, we replaced it with a white material. It seems to have really helped us keep our facility cool this summer. Of course, we use electricity to cool, and gas to heat. But we never had a lot of trouble heating our facility, just keeping the place cool enough to work in comfortably.
I don’t believe the article mentioned painting slant roofs, with shingles, white although I believe some have miscontrued it to mean that. The article is talking about government facilities and private facilities that have flat roofs. That is a simpler, less expensive construction technique and used quite often in government and corporate buildings. If you have a slant roof and want to help keep that attic space cooler, go to my store (SEMOsolarstore.com) and look into solar attic fans. You can run it in the summer when it’s hot to help keep your attic temperature down, and disconnect it or more it in winter to prevent it drawing heat out when you DO want it up there. Browse the store and be creative. Experiment a little and have fun.
July 8th, 2009 at 5:18 pm
While white paint will help it is not the most effective or efficient. You have to replace it every 3-5 years. Most paints are not good for the environment. A coating that I offer is a water based ceramic that reflects over 99% of UV, 92% visual light and over 99% Infra Red. Also has the advantages of being a moisture barrier, ability to block mold, mildew, and wood rot, blocks 68% of sound and has a class “A” fire rating that can help you save on your homeowners insurance. It is made to remain flexible and can be combined with other products to do a number of things, all while providing an “R-19″ insulation. Guaranteed for ten years and has been tested up to 15 years with less than 3% loss of efficiency. I know it sounds too good to be true!! I searched high and low and came across this product. It has helped me help my customers afford renewable energy systems for their homes by increasing their energy efficiency. Combined with several other low-tech apps like window film, caulk, timers, and vents they are able to save money and reduce their carbon footprint. It’s a win-win.
July 13th, 2009 at 5:32 am
White ( or light might look better ) shingles would probably last longer because the temperature of a sun bathed roof would be nearer to 110 degrees than the 165 degrees of a dark roof. The same applies for car colors. A dark car sitting in the sunlight for a couple of hours will attain the higher temperature inside the car. That might accelerate the degradation of the interior fabrics. And how long does it take for the air conditioned car to cool down; remember that 165 degree car is 3000 pounds of hot metal and glass that you must also cool down.
I have suggested but never gotten a reply to spreading light colored sand on top of fresh hot and soft asphalt paving to reduce the same high temperatures of the roadways. These high temperatures are a significant cause of the degradation of all sun exposed asphalt surfaces.
Other than a bicycle or walking, diesel powered cars would be highly desirable. Could you imagine Ford offering a Taurus sized vehicle that got 50 MPG ??? Or a Chevrolet Malibu ?? Ford already offers a smaller diesel powered car in Europe that is rated at 69 MPG but they won’t sell it here. Mercedes Benz has a diesel powered car that will accelerate from zero to 60 MPH in 6 seconds and is rated at 37 MPG. Europe is 50 percent diesel now.
Gasoline is a highly volatile and explosive fuel. Many people burn to death from gasoline fires following accidents.
September 17th, 2009 at 11:40 am
We looked at installing a 400,000 square foot roof in Utah. After figuring the the summer and winter advantages of each system it came out to be about the same. Also the employees of some of the roofing companies we talked to mentioned that the white roofs don’t handle freeze thaw cycles well and therefore are very troublesome in our region. They said that the installations they have done down south have faired much better than the ones they have installed up here.