http://www.cleanenergy.org/2009/06/08/step-two-solar-lighting-and-hot-water-system/

SACE | Southern Alliance for Clean Energy

Step Two: Solar Lighting and Hot Water System

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Following energy efficiency changes, the Smiths determined that solar tubes were needed to bring natural light into dark hallways and rooms rather than installing energy-demanding light fixtures. Seven 160 DS passive-solar tubular day lighting devices were installed in the roof, reflecting natural light into the home. At a few hundred bucks, these economical devices are an option for most residential homes, and their pleasing, natural white light is often preferred in comparison to the normal light bulb glare. When looking at an overview of electricity production for a home, the hot water system can become a drain on bills. After careful consideration, the Smiths decided to purchase a Schuco Slim Line Domestic Hot Water System. The two panels they chose are roughly two inches thick, and were nicely installed, lining up with the other solar PV panels. A solar hot water system can be one of the most efficient ways of using solar energy. And because solar radiation can be immensely powerful, the energy produced by sunshine on one square foot of roof in one year is predicted to be equal to 2.5 gallons of oil. On a cloudy winter day, two or three collectors can supply enough hot water for an average family.