"There's not too much you can do about the costs of food. There's not too much you can do about your mortgage," says Liz Robinson, the group's president. "But you sure can do a whole lot about your energy costs."

Robinson says during the summer, one of the highest energy costs is typically air conditioning; but there are other ways to keep cool.

"We have a housing stock in Philadelphia, a brick row home with a flat black tar roof, which if unshaded acts like a brick oven," she says. "It's a housing stock built to retain the heat, not to release the heat." Those rooftops contribute several degrees to a building's temperature, increasing the need for fans and air conditioning.

By covering black tar roofs with a white, reflective plastic coating, Robinson says indoor temperatures drop by several degrees. The Energy Coordinating Agency is treating the roofs of 400 Philadelphia buildings in a pilot project to test the efficacy of residential "cool rooftops."

The entire 6200 block of Catherine Street in West Philadelphia has been transformed into a cool block with white roofs. Resident Watson Eaddy says that's made a big difference on his energy consumption.

"I have two air conditioners, one upstairs and one downstairs," says Eaddy. "I haven't put either one in this year." Eaddy says before the reflective surface was put on his roof he would spend the summer with fans and air conditioners blaring. Now, he says his house is cool even when he's cooking in the kitchen. And in the winter, the additional insulation provided by the extra coat on his roof helps keep his house warm as well.