More and more US homeowners are turning to rooftop solar, as energy bills and power ... on installers and a handy Solar Calculator to estimate system size, production, cost, and savings.

Israel's Ministry of Energy and Infrastructure, in collaboration with the Israel Mapping Center, has launched a tool that calculates the potential and expected income from rooftop solar installations ...

once you've bought the solar panels, the energy she produces is free. A solar-powered calculator. Its solar cells are just above the buttons, on the right. These cells generate the energy needed ...