Earth Equity News

Solar Hot Water Systems Should Be a Priority. Commentary by Larry Hunter, NYTimes, February 9, 2009. "But after conservation, one of the most effective and efficient steps the government can take is to encourage the use of solar hot-water systems -- a well-developed and relatively low-tech method for using the sun's energy. Solar hot water systems are not as well known as the electricity-generating solar panels that use photovoltaic cells to gather energy. But hot water systems are more efficient than photovoltaic systems and can create the same amount of useful energy with fewer panels. Water heating accounts for a large share of a home's energy use -- typically the largest share after heating and cooling... Three 4-foot-by-8-foot panels (covering a total area of 96 square feet) can, in full sunlight, deliver about 4.5 kilowatts of heat -- enough to heat about 50 percent to 80 percent of the water used by a family of four. The cost to install such a system, including the panels, a water storage tank, piping, a pump and control electronics is usually less than $10,000. In comparison, a photovoltaic system that can produce 4.5 kilowatts in full sun requires 11 like-sized panels and costs about $40,000... homeowners are eligible for a federal tax credit on solar heaters of up to 30 percent of the installed system's cost, with a cap of $2,000. If Congress and the Obama administration were to raise the credit to 40 percent or 50 percent, and the cap to $5,000, it would reduce the payback time to only six to eight years. At the same time, we would be taking a step toward a sustainable energy future." Larry Hunter is a professor of physics at Amherst College.