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May 28, 2009

Lighten up (your roof) to fight global warming

It seems US Energy Secretary Steven Chu is urging everyone to put a white roof on their houses to help fight global warming. This from Al Tompkins at Poynter Online, who read it in the London Telegraph.

Hadn't thought about it before, but white or light-colored surfaces reflect sunlight, while dark ones absorb rays and heat up.  That's another reason why scientists are concerned about melting polar ice caps (besides the threat of sea level rise) - the white snow and ice help keep the earth cool by reflecting sunlight, while rays beating down on open ocean and land warm it up.

Chu, a Nobel Prize-winning physicist, was quoted in the Telegraph estimating that putting light-colored roofs on all the world's homes and replacing black asphalt with a lighter colored pavement would offset 11 years' worth of climate-warming emissions from all the world's cars.

A study co-authored by a scientist from Lawrence Berkeley National Laboratory in California (which Chu ran before joining the Obama administration) backs up his suggestion that converting a black roof to white would help offset the 10 tons of carbon dioxide emitted annually by the typical US house. 

And if fighting climate change isn't reason enough, it also ought to help reduce air conditioning bills in the summer.  By one estimate, white roofs everywhere in the US could save $1 billion in energy costs annually.  

There's no plan, apparently, to push this bit of geo-engineering on a national level - at least not yet.  But California, arguably the greenest of states in the US, already requires white materials on flat roofs, and in July will start requiring "cool-colored substances" on sloped roofs as well.

Anyone doing this in Maryland?

Posted by Tim Wheeler at 7:11 AM | | Comments (9)
Categories: Going Green


Yes! Civic Works' 3E Energy Solutions team applies a white heat reflective roofing system called a "Cool Roof".

The Cool Roof is ideal for the flat Baltimore rowhouse roof and our Cool Roof product is Energy Star approved (meaning you can access the energy tax credit to offset some of the cost of the roof).

The Cool Roof lasts longer because it reflects the sun's heat. Dark colored roofs constantly expand and contract causing them to crack and deteriorate. Civic Works' Cool Roof comes with a 10 year warranty against leaks.

Call 410-366-8533 to get a free Cool Roof estimate.

Civic Works is a 501 (c ) 3 organization and Baltimore's service corps.

Hey, Secretary Chu, Good thing there's not a Depression going on out here, with huge numbers of people out of work and most of the rest of us wondering if this Friday will be Pink Slip Day, huh? So we can all afford to just slap a new roof on the ol' dwelling!

This is the first statement I've marked from the Energy Secretary, and now I've got him pegged as Not Inhabiting The Real World and Lacking A Clue. I will filter every word to come out of his mouth through this.

Thanks for calling this to our attention.

Wouldn't white roofs increase heating costs in the winter as the heat is reflected instead of being absorbed into the building? I wonder if this was considered in the study.

I am about to have Gerry Donahue of Nashua NH put a two-tone patina metal roof from Classic Metal Roofing on my circa 1880 island cottage on Highland Lake. If this is bad for the environment I'll stop using hairspray. It's a beautiful roof and white would, frankly, turn the same color as your white tennis shoes in time.

I have a reflective coating (fibrous aluminum, I believe) on the roof of my rowhouse, and my neighbor on one side has a black tar roof. You can tell a huge difference when you're up on the roof in the summertime. The darker side is MUCH hotter. Flat roofs have to be recoated every couple years anyway, and the reflective coating lasts longer, so even if it's slightly more expensive (and it's really not that expensive), the longer time between coatings will pay for it.

The cooling season in Maryland lasts longer than the heating season, and if your roof is well insulated, it will keep the heat in a lot better than it will keep the heat out (that's what reflective barriers are for). So in the end, it makes a lot more sense to have the lighter colored roof, especially in urban areas (like Baltimore City).

As for Eve's comments, I'm quite sure he wasn't advocating everyone go out immediately and replace the roof. Roofs wear out, and when they do, you should replace them with a lighter color. Your vitriol and sarcasm are uncalled for.


Actually, there is a connection between the need to re-coat flat roofs as Cool roofs and the problem of rising unemployment that is the result of this deepening recession.

At Civic Works we recruit unemployed and underemployed Baltimore residents and train them for in-demand "green" jobs. One of those jobs is applying a heat reflective roof system and tightening up residential properties to be more energy efficient.

Let's support DOL's effort to fund "green" job training projects. The right projects will retrofit homes to be more energy efficient (Cool Roofs as well as Air Sealing and insulation), and will do so while training folks who most need employment on-the-job.

It's a "win win". Solve two problems simultaneously.

Fund projects that make real time improvements that result in long term savings for homeowners (as well as improved comfort and health and safety), while creating good green jobs.

Some of these efforts are already underway and others are in the planning stages. Tell your representatives that we need more.

Follow this link for more info on national efforts of this type:

Hashem Akbari, the Berkeley Lab scientist best known for his cool-roof research is one of the panelists in this video of Berkeley Lab's recent Science at the Theater. The moderator's questions begin at about the 40-minute mark. Akbari also answers a number of viewer questions at the end of the panel presentation.

How about all black-hair dudes in Washington hearing white wigs? That would also help reflect the heat, mainly the heat coming from all Americans fed up with the idiocy generated in Washington.

This is a good step towards environment safety . it should be implemented sooner.

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About the bloggers
Tim WheelerTim Wheeler reports on the environment and Chesapeake Bay. A native of West Virginia, he has focused mainly on Maryland's environment since moving here in 1983. Along the way, he's crewed aboard a skipjack in the bay, canoed under city streets up the Jones Fall from the Inner Harbor, and gone deep underground in a western Maryland coal mine. He loves seafood, rambles in the country and good stories. He hopes to share some here.

Contributor Christy Zuccarini has been blogging about the local DIY craft scene for a year for She brings her pespective on all things handmade to B'More Green, where she will highlight projects you can do yourself as well as crafters who are integrating sustainable methods and materials.

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