Efficiency ratings for solar panels should help prospective buyers

Solar energy shoppers will soon be seeing efficiency labels similar to the mileage ratings on automobiles and the energy labels for major appliances. Like the more familiar labels, those on solar panels will give the shopper a better idea of how much heat different products will produce. Unlike the federally mandated automobile and appliance ratings, the solar labeling is being done voluntarily by the industry.

For four years solar manufacturers have been trying to come up with a rating and certification system for their products. Reputable manufacturers and retailers of solar hardware have felt such a system was necessary to increase public confidence in their wares since questionable hardware and practices have beset the new industry.

However, the debate over how best to do this on a national basis has been a difficult and prolonged one. A number of states like California and Florida went ahead with their own rating programs. The Air-Conditioning and Refrigeration Institute and the Solar Energy Industries Association both started certification programs, further complicating the matter.

Now it appears that the Solar Rating and Certification Corporation (SRCC), set up by the solar association, will set the national standards for solar equipment. Recently, the State of California decided to end its rating program in favor of SRCC. And, since California has the largest solar market in the US, its decision is considered pivotal.

The certification program is extremely important to the solar industry in California, Arizona, and Florida, because only certified solar panels qualify for state income-tax credits. Even where substantial tax advantages do not hang in the balance, the rating system should help the solar consumer considerably.

The SRCC label rates five categories of collectors (from simple pool heater to industrial applications) in three operating levels: full sunlight, partly cloudy, and overcast. Like the Environmental Protection Administration mileage ratings for automobiles, the figures are relative, not absolute. But they should enable consumers to compare the performance of different collectors on a uniform basis.

Currently, the ratings apply only to the panels and not an entire solar system. System ratings are currently under development. Also, Underwriter Laboratories is working on a collector safety standard and another group is working on tests of collector durability.

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