Don’t get burned by solar roof shingles

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Over the past decade, renewable power sources have become an ever greater part of the energy supply. Solar energy is a particular favorite among utilities, businesses, and even everyday homeowners. Massachusetts has been a leader in solar installations, according to the Solar Energy Industries Association, and the state's capacity is expected to keep growing.

For homeowners interested in jumping into the solar movement, but wary of the aesthetics of traditional photovoltaic panels, solar shingles seem to offer an elegant solution. These roofing tiles are made with a thin solar film and sturdy base that allow them to be integrated into a roof alongside traditional shingles. They've been around for more than a decade, and getting more affordable as the technology has matured. So a reader wants to know: Have solar shingles evolved to the point that they are a good idea?


Sorry to disappoint, but probably not.

It comes down to performance, said Paul Lyons, president of Cambridge solar consulting business Zapotec Energy. Because shingles are laid onto an existing roof, they may not be oriented for maximum efficiency. More important, however, is efficiency. Lying flat against a roof, solar shingles get hotter than conventional solar panels. And a hot solar cell is an inefficient cell, Lyons explained. The heat creates resistance that makes it harder for electrons to flow freely. Panels are simply better at producing electricity.

Nor do the shingles hold up as a roofing material, Lyons said, especially in New England, where the weather ranges from pelting ice to sweltering heat. Solar shingles just try to do too much, he said.

"You have a single system that is not necessarily a good roof and it is a poor-performing solar photovoltaic system."

Furthermore, the new industry is still in flux. No single player is entrenched enough to guarantee it will be sticking around to provide replacement parts, service equipment, and honor warranties. In fact, just last month, Dow, one of the major producers of solar shingles, announced that it was pulling the plug on the product (though it will continue to support existing warranties).


So it seems that solar shingles are not the best bet for a Massachusetts homeowner quite yet. But given the growing interest in renewable energy and the often breathtaking pace of technological development, they are worth keeping an eye on.

Have a consumer question or complaint? Reach Sarah Shemkus at seshemkus@gmail.com.