Give Al Gore credit for putting his money where his mouth is. Gore recently completed renovations to his Tennessee mansion to make it a model of energy efficiency and sustainable design. The home now boasts solar panels, geothermal heating and a rainwater collection system. He also replaced the home's incandescent bulbs with compact fluorescent bulbs, which as Renovate Your World fans know, are about 100 times more efficient. As a result of the improvements, Gore's electric bill was down 11 percent this past summer. Not bad considering most homes in the area used 20 to 30 percent more electricity than the previous year during a record heat wave.