REGION: Cool roof coming to neighborhood near you

Energy conservation pioneer teaches overseas lesson

By DAVE DOWNEY - Staff Writer | Sunday, July 20, 2008 7:24 PM PDT ∞

Michael Wolske, construction manager for Hunter Industries in San Marcos, recently installed a "cool" roof on a 100,000-square-foot warehouse. (Photo by Waldo Nilo - Staff Photographer)

A state mandate to cover new, flat industrial buildings with so-called "cool roofs" that keep structures cooler during summer is about to expand to residential neighborhoods.

The California Energy Commission recently adopted rules that will require builders to frame houses with light-colored roofs that reflect the sun's heat. Homeowners will have to switch to the greener models when they replace aging, leaky roofs, starting July 1, 2009.

On Thursday, the state Department of Housing and Community Development incorporated the cool roof mandate into the nation's first green building code.

The cool roof is something Art Rosenfeld, a state energy commissioner widely credited with sparking California's energy conservation movement in the 1970s, has been advocating for several years.

Rosenfeld said the product has the potential to curb the need for air conditioning by 20 percent, lowering the demand for new power plants, slashing emissions of greenhouse gases associated with global warming and cooling our cities.

"The earth is like a greenhouse," he said. "Real greenhouses work well in the winter and they overheat in the summer. So you want to open up the glass in the summer. But I don't know how to open up the atmosphere."

Cool roofs can help curb that overheating, he said.

Area cities have been heating up steadily, in part because of the global increase in carbon dioxide levels, but mostly as a result of something weather wonks call the "urban heat island effect," said Bill Patzert, a climate scientist at NASA's Jet Propulsion Laboratory in Pasadena.

"In most of Southern California over the past century, average temperatures have gone up about 5 degrees Fahrenheit," Patzert said. "In the areas that have had the biggest growth, like San Diego and the Inland Empire, you really see it there."

The increase is most pronounced at night. He said overnight lows are up about 7 degrees while daytime highs have increased 3 degrees.

"All this area was dry chaparral that would heat up during the day and cool off at night, and now it is golf courses, lawns, shopping centers and freeways," Patzert said.

Because of heat-absorbing roofs and roads that continue to pump out hot air long after the sun goes down, the area tends to cool more slowly at night than it did 100 years ago.

Rosenfeld said the cool roof strategy has the potential to reverse that trend by sending heat that otherwise would be absorbed in buildings back out into space.

That point is hard to miss at Hunter Industries in San Marcos. Earlier this year, the irrigation equipment company opened a 100,000-square-foot warehouse with a white roof.

"When you're on the roof during the daytime, you can feel the heat coming off of it," said Rod Lauman, Hunter facilities manager. "It really reflects the heat."

Mediterranean influence

California's move to the cool roof reflects centuries of experience in countries that ring the Mediterranean Sea. There, most roofs are white.

"In most parts of the world, they think we are crazy for having dark roofs," said Rosenfeld, in a telephone interview last week. "We ought to have known what the pharaohs knew for 5,000 years ---- their temples had white roofs."

Rosenfeld said California finally is catching on to something much of the world has known for a long time: That light-colored rooftops are ideal in hot climates because they reflect the sun's rays and resist absorbing its heat.

Such roofs keep the buildings beneath them cooler and cut the need for air conditioning, he said.

Experts say the temperature on the surface of a dark roof can reach 160 degrees on a hot day.

"The sun's beating down on your roof all day, and that translates directly into increased air-conditioning load," said Gene Rodrigues, director of energy efficiency for Southern California Edison.

And state officials say light-colored, insulated materials can hold the mercury down by 50 to 60 degrees, holding down the temperature inside buildings and trimming the electricity bills associated with cooling them by up to 20 percent.

At Hunter Industries in San Marcos, where a ventilation system works in tandem with the white roof, the temperature has remained in the low 80s this summer, even during heat waves, Lauman said.

With a standard roof, he said, "it would have been in the mid-to-upper 90s."

Frosting on the cake

But while many new industrial roofs are white, it's not as if the residential roof of the future will have to look like something one would expect to see in, say, Casablanca. State officials built flexibility into the regulations to allow a wide variety of colors, and even darker ones, as long as they are made out of materials that resist absorbing heat.

"From the street, your house is going to look exactly like your neighbor's and it will be fashionable," said Adam Gottlieb, a spokesman for the energy commission. "It's not like you're going to stand out like a sore thumb."

But those with lighter colors will get the best results.

Rosenfeld said most homeowners can expect to save between 5 percent and 10 percent on monthly electricity bills. "If you go to white, you'll save 20 percent," he said.

Experts say cool roofs may last longer than conventional ones because they don't get as hot, and expand and contract as much.

"That's like the frosting on the cake," Rodrigues said.

But Paul Vujica, senior project manager for Swinerton Builders in Rancho Bernardo, a general contractor preparing to build a 161-room hotel at Valley View Casino with a cool roof, said no one knows for sure because the new products haven't been around long enough to compare.

"The jury is still out on the overall life span," Vujica said.

He said cool roofs tend to be 5 percent to 12 percent more expensive than conventional roofs.

In some areas, rebates are available to offset a portion of the difference.

Riverside County residents can get rebates from Southern California Edison if they trade old hot roofs for cool ones.

Rodrigues, of Edison, said the one-time rebates amount to 10 cents or 20 cents per square foot of living space, depending on the slope of the roof, or up to $400 on a 2,000-square-foot home.

Rodrigues said anyone from central Los Angeles to the desert is eligible for a rebate. Those who live in the thin, cool strip along the coast are not.

A bright idea

San Diego Gas & Electric Co. does not offer residential rebates. That, said Rachel Laing, a company spokeswoman, is because many customers live in the coastal zone, where it takes 18 to 20 years to recoup one's investment in a cool roof.

"In a place like Modesto or the Imperial Valley, it would probably have a very short payback period," Laing said. "But here it wouldn't."

However, she said the utility does offer rebates to businesses that install cool roofs as part of a broader package of measures to make their buildings more efficient.

Stephen Kapp, technology resources manager for California Center for Sustainable Energy in San Diego, said businesses have installed dozens of cool roofs around the region in the last couple of years, many of them on new big-box retail stores and government offices.

"They are certainly bright when compared to your typical roof," Kapp said.

And Rodrigues said the cool roof is proving to be a bright idea for working with the region's most abundant resource.

"The reason people move to Southern California is the sun shines and the weather is beautiful," he said. "But the thing that never escapes the sun while we hide in the shade or in our houses is the roof of your home."

For information on Southern California Edison's rebate program, go to www.sce.com/RebatesandSavings/Residential/_Heating+and+Cooling/CoolRoof/.

For information on the California Energy Commission's cool roof program, go to www.energy.ca.gov/title24/coolroofs/index.html.

Contact staff writer Dave Downey at (760) 745-6611, Ext. 2623, or ddowney@nctimes.com.

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Pre-Registration Comments[-]Go to Top

Billy wrote on Jul 20, 2008 10:22 PM:Years ago my research proved that an all white roof does reflect a lot of heat - in both the summer and winter. The white roof will reflect the heat in summer causing use of less electricity to cool the house. In winter it will reflect heat here in CA causing an increase in heating electricity and/or gas. I found the best to be a light brown which is effective for both.
The truth is a double roof that lets the wind blow between the two would be ideal in keeping the temp down in the summer. Of course there would have to be about a foot space between the two roofs. The flow of air between the two would carry the heat from the upper roof away.
Now where would a person get such an idea? Some of the homes in the area built many, many years ago utilized such a design coupled with the cooling effect of adobe.
Now if someone could come up with a roof that would go white during the day and black at the most advantageous time in the evening,turning back to white in the morning, then we would have something.
Copyright 2008 Billy lol

Todd wrote on Jul 21, 2008 3:09 AM:Generally, for warm climates, the benefit of a "cool" roof far far outweighs any "heating penalty" as it is called. Even in northern climates, if you have a well vented attic (as is required by code and to avoid ice damming), the heating penalty is minimalized.

In addition to light colored roofs there are also metal roofs and perhaps even tile products using special reflective pigments for energy efficeincy. A lot can be done with ventilation, too, in order to make a roof cool.

Flabbergasted wrote on Jul 21, 2008 7:05 AM:It's great that the government is now regulating the color of our roofs to be more "green". I can't wait until they force us to buy biodegradable furniture made out of corn husks.

Just the facts wrote on Jul 21, 2008 7:59 AM:In other parts of the world, developers build homes suitable for the climate and location...that's why white roofs are common in warm weather areas.

In the US, developers build what is cheap, easy and best for their bottom line.

Building codes are there to balance greed and need.

Krypto wrote on Jul 21, 2008 12:01 PM:I grew up in the Imperial Valley(north-end), I know for a fact that white roofs were prevelant out there, as my family house had it with gravel. Still does. The prevailing temp out there was in the high 120's, it has been cooling off since then, but still hot. I live in S.D. now, and don't go to the Sea during the summer, as it is too hot for my acclimated butt now. I see these roof ventilators start moving early in the morning, I guess because of the dark roofs. When I redo my roof, it will be with a light roof.

Flummoxed wrote on Jul 21, 2008 12:50 PM:I have a black asphalt shingle roof and a highly insulated attic. Why should have have to replace the black roof with a light colored roof if my attic is sufficiently insultated, other than silly big government regulations that will be a great excuse for the roofers to charge me a higher price to comply with the new con artist envro regs? No, I don't have AC either, don't need it with the insulation.

Freedom lover wrote on Jul 21, 2008 12:57 PM:Reminds me of the government mandated low flush toilet rip off. Low flush = having to flush twice.

What happens to folks along the beach and in the mountains who need a black roof to act as a heat sink to counteract cold nights? Sorry, no can do?

Let the consumer's dollar determine what they buy, not the bureaucrat.

Karl wrote on Jul 21, 2008 1:25 PM:Just the facts
[-] wrote on Jul 21, 2008 7:59 AM:

Building codes have nothing to do with balancing "greed and need". Building codes were established to make sure our structures are safe.

John E wrote on Jul 21, 2008 1:40 PM:When I re-roofed the house 16 years ago, I chose the lightest color the Elk Prestique Plus line offered. Light-colored roofs are a superb idea in our climate zone. Lighter-colored asphalt for parking lots might not hurt, either.

I did it wrote on Jul 21, 2008 2:07 PM:I put a light colored roof on my house. It really helps keep my home cooler. Plus I asked the neighbors if they didn't mind, they are above my roofline, and they loved it! Less radiant heat coming up into their living space! DO you get it now "Flummoxed"? It's not just about you and your abode. It's about the neighbors, the neighborhood, power consumption, the world.

Vista Resident wrote on Jul 21, 2008 3:01 PM:Thanks to the California Energy Commission for planning ahead with this easy-to-do step forward. This sounds like a really easy way to save energy. The time has come for big changes to prepare for our future energy needs.

When I first moved to Vista, the one thing I didn't like about this area was all the orange tile roofs. After awhile I kind of got used to them. But, I think lighter roofs would look a lot better. Anyway, the article says that many colors will be allowed even though white saves the most energy.

Johny On The Spot wrote on Jul 21, 2008 3:14 PM:As far as I am concerned the "Evironmental Wackos" have struck again. It is one thing to speculate these things and possibly to even suggest that one color might be better than another, but to MANDATE light colored roofs across the state is incredibly lame. Not to mention that it costs as much as 20% more to get a light colored roof according to this article.

Why doesn't the legislature mandate white roads, since we have many more square miles of our state covered with black asphalt than we do dark colored roofs. Then what about dark colored cars... where will this debacle end and all because some eviron-mental-ists determined that light is good?

I swear our reps are too far out there when it comes to stuff like this.

Too Much Time wrote on Jul 21, 2008 5:14 PM:Yes, our reps appear to have way to much time on their hands. Not enough to balance a budget or anything as mundane, but plenty to deal with plastic bags and the colors of our roofs. I personally live on the coast, don't even see the sun for 50% of the summer due to the marine layer, don't have an air conditioner (do I get some sort of "green" credit for that?), and all I've ever needed to do is ventilate the attic and everything is fine. Global mandates like this are for the weak minded (so is fighting plastic bags when what we need to do is limit development until we catch up on the energy and water needs).

Mike S. wrote on Jul 21, 2008 6:02 PM:To Johny (is that really how you spell your name?) You seem to entirely miss the point. No energy is currently being used to air-condition road surfaces.

It is nice to imagine ourselves as individuals in our own castles interacting with an impersonal market that is there to cater to our every whim, but that's not the reality. What you drive affects what I pay for gasoline. How you drive affects my insurance rates. Whether your roof is black or white affects the electricity demand profile, which affects my electricity rates, not to mention global climate.

Vista Watchdog wrote on Jul 21, 2008 8:07 PM:So, if I cover my roof with Photovoltaic (Solar) cells, which happen to be a very dark blue (almost black), will I be penalized? And what about my solar water heater panels that are very black? You know, I even had my pool done in a dark color as it significantly reduces the need for running the solar water heat pumps during the summer (and even in the winter to some degree).

I should add here that when I had my PV systems added to the roof of my house my electric bill also went down as a result of using less electricity to cool the house! Yes, the added layer of PV cells mounted about 6 to 8 inches above my regular roof, actually provided shade that in turn decreased the heat buildup in the attic and thus less need for A/C.

Then there are the trees! Yes, I said TREES! Some 30 years ago I planted a bunch of trees in my vacant yard. Now they are nice and big providers of shade! I have been tracking the temperature at my place over the years and have noticed a pleasant decrease in temperatures over the years. Must be all the trees I and my neighbors planted (or else this global warming is a farce. Could that be why the Southern ice sheet is at an all time maximum for the last 50 years? No, must be something like the Ozone Hole down there is doing something to build ice even while the Earth warms!).

Yep, Mother Nature is wonderful when you take full advantage of all that she provides. And when Government steps in and mucks things up, that is when she unleashes her furry on mankind. So, beware what your elected officials are trying to tell you: You just might find out it cost more than it's worth!

ecco wrote on Jul 21, 2008 9:58 PM:Next they the govt will mandate no roofs so they can check up on you easier. Recycling pop cans, not too long in the shower, not more than 4 squares of tp...
SDG&E has no rebates because all of their cust live on the ocean? I must be sending my elec payments to the wrong company. As usual SDG&E spews more lies. Their territory goes from the coast into the desert...

ecco wrote on Jul 21, 2008 10:06 PM:Plant grass and flowers on the roof to cool it naturally

Vista Resident wrote on Jul 22, 2008 12:09 PM:T Bone Pickens testified before Congress and is being televised on CSPAN today. He -- and others -- have said that we need a project like the Apollo Moon Project to work towards getting all of our energy from America. $780 billion a year flows out of the US each year for our energy needs (I think that's what he said). That's a recipe for disaster for the American economy.

T Bone believes part of the solution is being frugal with what we use with energy savings wherever possible . He doesn't know if it is possible to produce all our energy here within 10 years as Gore has suggested. But, sitting around on our duffs and doing nothing is just pure laziness and is part of why we're in such a pickle.

Carter tried to get alternative energy going with government policies and tax incentives. But then successive presidents took that out and put us back into our old patterns. When energy sources are localized and diverse, that discourages monopoly pricing -- like we are now getting with oil.

If we just keep doing things the way they've always been done -- and just sit around and do nothing -- then our energy security situation will only get worse.

One advantage of this government roof mandate is that then HOA associations won't be able to tell you that you can't do it.

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