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Company: Dow Chemical
Price: $25,000 for a typical installation before any rebates
When available: 2011

Dow Chemical's new photovoltaic shingles mimic the appearance of conventional asphalt shingles and their installation is nearly as simple -- but they'll be able to produce between 40% and 80% of a home's electric needs, according to Jane Palmieri, general manager of Dow Solar Solutions.

"They'll offset a sizable portion of the owner's energy use," she said.

The shingles will produce most of their power when there's no one home to use it, during the day. That's also when power is most in demand to light and cool office buildings and run machinery. Homeowners will be able to sell the power back into the utility grid and get "paid at peak rates," said Palmieri.

One of the myths about solar is that the photovoltaic cells have to be in sunny places to work well. That is not true. Germany, for example, where cloudless days are few, is a leader in using solar technology.

"It's viable wherever the cost of electricity is high," said Palmieri.

The company is estimating that the "pay-back" time will be five to 10 years. The shingles will last 20 years or more so they'll produce profits for the homeowners at least half their life.

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