March 14, 2008 3:55 AM PDT
Solar thermal systems have been around for decades but are catching on again as people look to make their houses "greener" and cut down on energy costs. Older solar hot water systems used a simple black panel to heat up a liquid which then heats a home's hot water. More modern hot water systems use evacuated tubes, filled with dark-colored "fins" that are made out of copper. Depending on state incentives, a solar hot water system can make up the initial cost within 5 to 10 years and run with little maintenance for decades.
Photo by Martin LaMonica/CNET News.com
