Thursday, December 2, 2010

Green Roofs Versus Solar Panels

When Scott Harris and Sarah Jack did a major renovation of their 1925 Teaneck, N.J., colonial in the summer of 2009, they kept the environment in mind — for example, choosing kitchen counters made of cement and recycled glass.

They thought about solar roof panels but rejected that idea when they were told that they’d have to chop down a towering tree that shades their back yard and house.

Instead, they installed a green, or living, roof. The greenery absorbs and filters rainwater, as well as adding insulation, which cuts heating and cooling costs.

For most homeowners, the biggest environmental impact of a roof is simply that it keeps the environment out. But there are innovations that aim to make the roof over your head an important tool in the effort to save energy and reverse global warming. And we’re not just talking about solar panels. There are cool roofs that reflect, instead of absorb, the sun’s rays; roofs made with recycled material; and green or “living” roofs, like the one on the Harris-Jack house.

“We wanted to do something to see if we could save on energy bills,” Harris said. “But it’s nice just to look out at it. Now when people come to visit, we have to bring them to the bathroom upstairs to look at the roof.”

Their green installation, on a flat section of roof at the rear of their house, consists of shallow trays holding a light, rocky soil and a mix of sedums, a drought-resistant, low-maintenance plant.

It was the first residential roof installed by Rob Schucker of R&S Landscaping in Midland Park, N.J., who also created a rooftop garden at Hackensack University Medical Center. He got interested in green roofs several years ago.

The cost of green roofs ranges from $15 to $35 a square foot — significantly more than a simple asphalt roof. The roofs require a structure strong enough to hold the plants and soil, even when the soil is saturated after a rainstorm. And some homeowners worry that if such a roof develops a leak, it would be more difficult to fix — though using trays lessens that concern.

But green roofs tend to last much longer, because the vegetation protects the roof structure from drastic changes in temperature, according to Jennifer Souder, a research manager at the Center for Green Building at Rutgers University.

“They can be a hard sell, because this is money you have to pay now,” she said. “But over the long period, they can be cost-effective.”

Meanwhile, even asphalt shingles, the workhorse of the roofing world, are getting an energy-saving twist. Asphalt roofs are the lowest-cost option, typically running $80 to $100 per “square” — a roofing-industry measure that’s equal to 100 square feet. That comes to about $1,000 to $1,200 for a 1,200-square-foot roof on a Cape Cod (not including installation charges).

But there are some new developments here, too — notably energy-saving “cool” roofs, which incorporate reflective granules to reduce the heat that comes into the attic.

GAF Materials Corp. of Wayne, N.J., the nation’s largest manufacturer of roofing materials, estimates that such roofs can cut homeowners’ cooling costs by 7 to 15 percent.

Cost, however, is an issue. The cool shingles cost at least 40 percent more than regular shingles, according to Tim Williams, director of marketing at East Rutherford, N.J.-based Allied Building Products. Many homeowners like the idea of saving energy but are reluctant to spend the extra money, he said.

Dean Logan, president of Complete Roof Systems in Dumont, N.J., said the reflective shingles don’t offer much benefit, especially considering their cost.

He said homeowners who want to save energy would be better off spending money on insulation under the roof.


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