Google launches online solar power calculator for homeowners

Ars Technica : This week Google introduced a project intended to encourage homeowners to install solar panels. All homeowners need to do is enter their address on the Project Sunroof landing page , and Google will determine how much sunlight shines on their roof. To do so, it draws on numerous data, including aerial imagery, three-dimensional roof modeling, shadows cast by nearby buildings and trees, Sun positions over the course of a year, and historical information on local cloud and temperature patterns. It then provides an estimate of how much money homeowners could save on their electric bill by installing solar panels, the costs of leasing compared with buying the panels, suggestions on how much of the roof to cover, and a list of solar providers in the area. Although Project Sunroof currently serves just three cities—San Francisco, Fresno, and Boston—the company says more will be added as the project progresses.