UPDATE: have a look at Clinton’s house below. Yep, that’s the big plan. Paint your roofs white. From the Atlantic:
I have no problem with saving energy, especially in the summer when power drain is excessive due to A/C load. California now requires most flat-roofed buildings to be white. As a testament to the potential cash savings, Walmart has installed white roofs on 75% of its stores in the United States. Roofs comprise over 20% of urban surface, so while painting them all white in a city, there’s still a lot of asphalt.
But paint roofs white has a downside as well as an upside. It depends on where you live. If you live in a mostly warm climate, say Miami or Phoenix, you’ll realize energy savings. But if you live in Minot,ND or International Falls, MN your white roof will not absorb as much sunlight in winter, thus requiring more energy for heating.
The point is, painting roofs white natiowide, willy nilly, without regard to the local climate, average temperatures, the number of days of sunshine etc. won’t be a full solution.
An idea like Cool Angle, might work, but is far more involved than a paint job.
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UPDATE: Reader John provides this image link to the former president’s home. Goose, gander, and all that. We look forward to seeing Bill lead the way.
Source: http://www.zillow.com/howto/FamousPresidentsHomes.htm
There are many white coatings but they are usually more expensive than the aluminum coatings that have been used for decades.
http://www.youtube.com/watch?v=5gDJSd0jilg&feature=related
Hu McCulloch and Keith R are basically correct: Painting the roofs silver is a much better color.
Silver or aluminum(ized) is better for another reason: A shiny silver also has low emissivity, which means it doesn’t give off heat, either. That means that in the wintertime the silver will be better than white, which will allow heat to escape.
One more factor is that the coarse texture of roof tiles provides much more surface area with which heat can be absorbed or emitted, The less surface area, the better. I recall a flat panel radiant portable electric heater from about 1980 that was very low temperature, but was coated with sand to increase the radiating surface. Smooth is better than rough.
To the people who say that roofs are a very small part of the US/world’s surface, so painting them white won’t make much/any difference: fortunately we don’t see the need to air condition roads, carparks, and so on.
We do however tend to use AC for homes, office and factories, which coincidentally tend to coincide with roofs. Therefore painting white (if the act of painting reduces AC – and perhaps heating – costs over the medium term) makes obvious sense.
Also worth remembering that the warmists have “demonstrated” that UHI has very little effect on temperature measurement. That is hard to reconcile with the idea that the colour of buildings, white or otherwise, makes a difference to the amount of heat absorbed.
Keith R says:
http://wattsupwiththat.com/2011/07/18/clintons-solution-for-the-jobs-crisis-painters/#comment-702659
that makes a lot of sense to me…
Some more ideas: chrome your roof, or paint it grey to split the diff between summer and winter, or use colour-changing paint (like sunglasses that get darker in the light), or give into the green agenda: demolish your house and move into a grass hut.
White roof? I think Clinton is just pining for the Whitehouse. Poor old schmuck is feeling irrelevant.
But I don’t think this is his idea anyway; I heard the greenies going on about this years ago.
@frank Kotler says: July 19, 2011 at 12:54 am
Second mirrored sidewalks. Or you could get glassphalt: http://en.wikipedia.org/wiki/Glassphalt
This reminds me of the idea to paint street signs with upper and lower case letters because they are supposedly easier to read, an idea Bloomberg supported for a while, it turned out the idea can from a company that makes sign paint.
Before we go off embracing this idea wholesale, I would like to see numerous real world peer reviewed studies done with a larger sample size than just Walmart, and with different roof types, and not funded by the paint industry. Even then I would be leery. There are plenty of studies showing that roundabouts work, but in my real world experience I hate them.
In any event, government should have nothing to do with it.
“The Great Jobs Debate” … paint your roof. How cynical.
What’s up with the United States of America? A former powerful and proud nation.
What looks like a reasonable proposal is the typical stupid-green feel-good idea.
Willis Eschenbach has done the math early in this discussion, showing how senseless it is.
We better make that clear instead of following the green “mega”trend.
Or let us turn it around somehow, as these guys have done with lightbulbs regulation: http://www.heatball.de/en/.
It’s so good.
Haters gonna hate…
I think it’s a great idea from the greatest U.S. President of my lifetime!
He didn’t say anyone should be forced to do it.
He didn’t say the government should give tax breaks to people who do it.
He didn’t propose a big government spending program to do it.
Clinton just said it would be good for America if it happens.
He said building owners would quickly save money by doing it.
A logical extension is that the U.S. Government should consider ways to encourage it, but that isn’t what the big dawg said.
This country would be in so much better shape if he had never left the White House.
Roger Knights-
What you have described is the norm for almost every home in the USA that was built without an attic. The soffits have vents along the underside that channels airflow to vents along the roof peak.
There is an airspace between the underside of the roofing and the insulation above the ceiling. These are typically not closed in winter, but otherwise act with a similiar effect as the added plywood above an existing roof.
I think white roofs might increase the ice-damming potential in northern climates. An advantage of a darker roof in the snowy winter is occasionally you get some bare spots which heat up quickly (with sunlight) and open roof ventilation pathways, which are usually poor to begin with, clogged with dust or wasp nests if not cleaned regularly. These roof bare spots also help to remove some of the winter snow cover via evaporation and help prevent it from building up.
With roof snow cover and blocked vents, the attic space heats up (regardless of how much insulation you have), melting the snow, which refreezes over the eves and gutters. It makes an ice dam, and water back up under the shingles and enters the home, causing major damage.
HenryP says:
July 19, 2011 at 7:56 am
Sorry Paul, but I am really not sure about that.
For example, if I look from the top (flying over) then my zinc galvanised corrugated roof seems to reflect a lot more light then the white walls (of my house). How do you explain that?
The appearance of ‘enhanced’ reflectivity that you’re describing is caused by the particular properties, rather than the magnitude, of reflection from different surfaces. Generally metal surfaces cause specular reflection whereas a matt white paint will cause diffuse reflection (http://en.wikipedia.org/wiki/Diffuse_reflection).
This is a list of materials showing absorption and emissivity properties for each: http://www.solarmirror.com/fom/fom-serve/cache/43.html
It lists ‘New Galvanized Metal’ surfaces as providing 0.65 absorption (0 to 1 scale) compared to various white paints 0.2 – 0.4. However it also lists various zinc substances with absorption of about 0.15.
After painting your roof white you’ll have to mount some near-black PV panels on it to make it even more Gaia-friendly.
>>DonS says: July 19, 2011 at 5:29 am
>>That is why we have an America and you have the idea that 4-story flats
>>close together are desirable living quarters.
And in which American town can you walk to the center or to the shops?
I suppose if you wish to live your life sitting in a traffic jam, you have the right idea for social housing…
.
Byz says:
July 19, 2011 at 12:05 am
“Regardless of the value of the work, if people work they pay taxes and more importantly get into the habit of working (you should see the youth over here in the UK they don’t want to work).”
I work in Germany and i got into the habit and i gotta kick it; it stinks; the government takes all my money and i’m wasting my life.
The runways etc at Thule AFB are/were painted white to avoid warping the runways. I lived in Bermuda for a short time and most of the roofs there are white, but they serve an additional porpose of water collection.
So these bozos (Chu et al) actually accept that a white roof makes a difference in heat absorbed?
Presumably they must accept that clouds do the same.
Are these the same bozos that believe in climate models which are completely unable to model clouds?
John Edmondson says: “To be fair, this is not a bad idea.”
Not bad. Just atrocious. Some dark, un-insulated roofs would benefit, but this is generally impractical. But what did you expect from Clinton?
Steve Oregon says: “There are many white coatings but they are usually more expensive than the aluminum coatings that have been used for decades.”
Yeah, and there’s a reason that white is more expensive: It actually works. A few months exposure, and the aluminum roof absorbtivity goes up by a factor of three. And you have to wash any coated roof down at least once a month. No easy answers here. I started looking at this in 1962 (when I was doing A/e ratio research for a space project.) Another factor to consider is roughness. Rough surfaces will not benefit as much as smooth ones. Painting shake shingles is a stupid notion.
@ur momisugly James Sexton “BTW, the painter wouldn’t pay any taxes here in the U.S. except the state and local sales taxes. We’re not going to pay them enough for them to pay fed income taxes. ”
Where is that documented? How do you support that assertion? Seems like a political not factual rant.
Good ol’ Mr. Clinton–first he wants Obama to whitewash the national debt:
http://www.theblaze.com/stories/debt-limit-showdown-bill-clinton-advocates-obama-ignore-congress-invoke-the-14th-amendment/
And now he wants to whitewash roofs. He’s in a painting mood.
anton says:
July 19, 2011 at 7:34 am
By deflecting light and heat, wouldn’t white roofs actually contribute to atmospheric warming? The solar energy has to go somewhere.
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I have often wondered the same thing.
This is a commercial vendor so take it with a grain of salt but;
“[snip] is proud to offer our customers products that have earned the US government’s ENERGY STAR label. [snip] Roof Coating exceeds the US ENERGY STAR guidelines for energy efficiency. [snip] reflects 83% of the heat from the sun. When installed properly, [snip] will reduce air conditioning energy costs by as much as 28%, depending on geographic location and individual building characteristics. Heat stress on the roof structure is virtually eliminated. “
Bystanders says:
“Where is that documented? How do you support that assertion?”
Since you seem to know it all, how much per hour will your imaginary roof painters be paid?
Jim Says: “I live in Vermont and I can assure you that my roof is white all winter. White paint is not going to change that in any way.”
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I used to live in Vermont,so I know what you’re talking about.
Great idea, Mr. Clinton. Why don’t you personally come on by and paint my roof, or you personally pay somebody from your own funds to paint it for me, since I can’t afford it?
And while you’re at it, you might as well pay to have the roof replaced entirely since the paint will no doubt ruin the shingles.
Or you could just STFU and butt the hell out of my life.
(I have light grey shingles on my roof; I don’t think they come in white. Also, the attic is well-insulated.)