TABE Practice Test 4

Keeping Cool from the Top Down

On a sunny July afternoon, the black roof of a store can become much hotter than the air around it. That heat does not stay on the roof. It moves down into the rooms below, and the air conditioner has to work harder to keep people comfortable.

For many years, most builders did not think much about the color of a roof. Dark materials were cheap and easy to find. But as summers grow hotter in many cities, people are looking at roofs in a new way. One answer is called a cool roof.

A cool roof is covered with a light-colored or specially made material that reflects sunlight. Instead of soaking up the sun's energy, the roof bounces much of it back into the sky. A coat of white paint made for roofs is one simple kind. Light-colored tiles and sheets are others. On a hot, sunny day, a cool roof can stay many degrees cooler than a dark roof next to it.

A cooler roof brings several benefits. Less heat enters the building, so the air conditioner runs less and electric bills can drop. Rooms on the top floor feel more comfortable, which matters in homes without air conditioning. When many buildings in a neighborhood have cool roofs, the whole area can stay a little cooler.

In the town of Bell Harbor, a group of volunteers decided to test the idea. They painted the roof of the community center white. The next summer, the building manager, Darnell Price, noticed the difference right away. "The upstairs meeting room used to be an oven by noon," he said. "Now people can actually use it." The center's summer electric bills also went down.

Cool roofs are not perfect for every place. In cities with long, cold winters, the heat a dark roof soaks up can help warm a building. A white roof may also need cleaning, because dirt and dust make it less reflective over time. Experts suggest that owners think about their climate before they choose.

Still, for many people in warm places, the choice is an easy one. A cool coating can often be added when an old roof is being repaired or replaced, and it keeps working every sunny day. Sometimes the best way to beat the heat is to start at the very top.