Leigh Peterson has one of the coolest roofs in Baltimore. Her rowhouse near Patterson Park sports a blinding white cap, topped by a row of shiny solar panels.
Peterson, 29, a graduate student at the Johns Hopkins Bloomberg School of Public Health, doesn't need to see her roof to know it's cool, though. She just has to count the dollars she's saved on air conditioning. She got her roof coated as part of a comprehensive energy retrofit of her 109-year-old house, and her August electricity bill was about half what she paid last year.
"I'm a grad student, so I'm always into saving money, because I don't have much of it," she said. "But I'm also environmentally concerned as well."
Peterson is one of a small but growing number of Baltimoreans putting energy-saving "cool" roofs on their homes or places of business. A new report by the Abell Foundation suggests white or cool roof systems like hers could help fight global climate change while also making the city a healthier place to live — and urged local and state governments to do more to expand installation efforts.
"Longer lasting, cost-competitive and often safer to install than traditional black roofs, cool roofs could become Baltimore's next climate mitigation priority and environmental target," concluded the report, written by Joan Jacobson, a freelance journalist, researcher and former reporter for The Evening Sun and The Baltimore Sun.
Ideal for flat or gently sloping surfaces, cool roofs involve more than slathering a coat of white or shiny metallic paint on an existing layer of tar. They come in two basic types, both intended to reflect sunlight and keep the building below from heating up as much. One involves applying a liquid acrylic coating that dries into a rubber-like surface, while the other features a thin membrane laid down over the roof to seal it.
They can reflect up to 80 percent of sunlight they receive, the report says. Studies show they can cut air-conditioning costs by up to 20 percent and even lower indoor temperatures inside buildings without air conditioning. White or light-colored roofs may reduce the amount of solar heat homes get in winter, but the savings in warm weather more than offset any extra heating needed when it's cold in all but the northernmost climes, studies show.
There are health benefits as well, advocates say. Kurt Shickman, executive director of the Global Cool Cities Alliance, said a study his group just finished in Washington found that in areas where cool roofs were installed along with tree plantings at the street level, heat-related deaths declined by 6 percent to 7 percent. This past summer's relatively cool, rainy weather resulted in 15 heat-related deaths in Maryland, about a third as many as in 2012 and the fewest since 2009, according to the state health department.
Cool roofs can cost about the same as traditional ones, proponents say. Installation and materials range from $3.90 to $9.50 per square foot, compared with $4 to $8.25 per square foot for an asphalt roof, according to the report. Upkeep on cool roofs also is less, because they don't heat up and crack as much.
New or existing roofs covered with liquid coatings can easily last a decade, the report said, and two to three times longer with regular recoating every five years. The membrane roof coverings generally require replacement of the existing roof first, but also can last 25 to 30 years with minor maintenance.
Hundreds of cool roofs have been installed across Baltimore since the first one went on a home in Charles Village in 1981, according to the report. The city's housing and community development department has helped pay for reflective roofs on about 130 homes occupied by low-income families, while Civic Works, a nonprofit group affiliated with Americorps, has installed another 150, according to John Mello, the group's green project director.
The city has since made cooling homes and businesses with reflective roofs part of its climate action plan, so municipal agencies are ramping up their efforts. This year, the report notes, the city got $2.8 million from the state to make grants to low-income homeowners to put cool roofs on 500 homes as part of a weatherization program.
The city also hopes to put cool roofs on 22 to 50 homes a year as part of its "Baltimore Energy Challenge," which works to install a variety of energy efficiencies in homes as well. Alice Kennedy, city sustainability coordinator, said she expected to spend about $100,000 a year over the next three years on the effort, which targets low- to moderate-income households.
But more could be done, the Abell report argued. It suggests Baltimore and Maryland imitate aggressive installation campaigns in other cities and states. In particular, Jacobson urged the city to mandate cool roofs on new and renovated structures as part of its green building standards, much as California has done.
"I think there's some real opportunities, looking at neighboring cities, to take what they're doing and do it in Baltimore," Shickman agreed. New York City, for instance, has worked with local energy companies and corporations to coat government buildings and require cool roofs on all new and renovated private buildings.
City Hall isn't prepared to go that far. Rather than require it, Kennedy said local officials hope that by spreading the word about the savings and other benefits building owners will readily embrace cool roofs.
"It's something we would definitely like to encourage," she said.
Many appear to have gotten onto the bandwagon already, Kennedy said. From her window in the Benton city office building downtown on Baltimore Street, Kennedy said, two-thirds of the roofs she could see have white or reflective coatings.
Washington, D.C., also has a cool roof law, Shickman said, but there developers already are embracing cool roofs as they strive to meet the voluntary green building standards set under the Leadership in Energy and Environmental Design program. Cool roofs are encouraged under those guidelines, he noted.
The Abell report also called for the state to make cool roofs eligible for financing and rebates now offered for upgrading the energy efficiency of a home or business. The state does have a goal of reducing energy consumption 15 percent by 2015, it pointed out.
The Maryland Energy Administration does not provide any financial incentives to install cool roofs now, but spokeswoman Devan Willemsen said that might be about to change. If lawmakers approve the funding, the state energy office is preparing to roll out a new competitive energy-efficiency grant program targeting low- and moderate-income households, and one of the upgrades the program would pay for is a cool roof.
"We're definitely in support of cool roofs," Willemsen said.
The Abell report also urged the city's school system to integrate cool roofs into its planned $1.1 billion overhaul of 40 school buildings.
Lighter-colored roofing materials went on about 20 city schools that have been renovated or weatherized, the report says. But those crushed-granite and ceramic materials don't yield the same energy savings a true cool roof would.
Keith Scroggins, chief of facilities for the city school system, said administrators are looking at cool roofs, as well as "green" roofs, those which have vegetation planted on them to absorb rainfall and control storm-water runoff.
"As we get closer to design of the first group of schools, we expect to decide on a variety of energy efficient options," Scroggins said.
With storm-water control a priority in Baltimore because of the Chesapeake Bay restoration effort, some might think green roofs would take precedence over cool roofs. Shickman said it's a false choice, as both can go on larger buildings, and with smaller structures the runoff controls can be installed on the ground.
The biggest problem with cool roofs, experts warn, is they can cause or worsen moisture damage if not properly insulated and ventilated.
Stanford University researchers also have suggested that cool roofs might actually warm the planet if they went global, because they'd reflect sunlight back into the atmosphere and warm the many fine particles floating in the air. That's a distant worry for now because cool roofs are nowhere near widespread.
Peterson, an area vice president of the Patterson Park neighborhood association, said she put leased solar panels on her roof first, as a hedge of sorts against rising electricity rates, then had the cool roof installed. It was part of a $3,000 complete energy retrofit of her drafty home, she said. Technicians sealed up cracks, put in additional insulation and installed a new hot-water heater.
The payoff: electricity bills of $100 to $120 for her 1,000 square foot home even with her central air running.
"That is pretty wonderful," Peterson concluded.
An earlier version misstated the size of Leigh Peterson's home. The Sun regrets the error.
Designed to reflect sunlight and have lower temperatures than traditional black or dark roofs.
Though many are white, they can be other colors as long as they include reflective material.
Ideal for flat or gently sloped roofs, best when put on new or replacement roofs.
Two basic types: "elastomeric" roof with a multi-layer liquid coating, reinforced with mesh, or prefabricated membrane sheet.
Can reflect up to 80 percent of sunlight, reduce air-conditioning costs by up to 20 percent.