The Hottest Home Improvement in 2011

That may surprise some of Mr. Hall's neighbors, who think that Dallas is often steamy enough. Mr. Hall says his sauna provides not only relaxation, but also a certain cachet with friends and colleagues. "We'll have clients over and instead of going some place for happy hour, we'll have a sauna, a couple beers," he says. "People think it's weird at first" but then are usually won over, he says. Saunas have been at the core of Finnish culture for thousands of years, a traditional toasty respite in a cold and snowy climate, according to the nonprofit North American Sauna Society, whose members are fans and merchants. More Americans are making space for sauna rooms, clearing out basements, converting closets and even partitioning off backyard sheds.