I talked to Mr. Egnatinsky about his solar hot water system. He installed two panels and two storage tanks, because there was one bathroom at the far end of the house. Most houses require only one collector panel and one storage tank, and the payback period is 3 to 5 years. For 2006 and 2007 there is a 30% tax credit available on solar hot water and solar photovoltaic equipment (with a $2000 cap per residential system), which shortens the payback on solar hot water to two years or less, depending on usage. For Mr. Egnatinsky's two-person household, it would have been more cost effective to install a recirculation line to the distant bathroom from the hot water storage tank. The recirculation line circulates hot water to the distant bathroom (either to a small storage tank there, or direct to faucets) and back to the main storage tank, through insulated pipes. Detailed information on tax credits is available online at www.seia.org .
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