Google wants to help you harness the power of the sun. A new service called Project Sunroof aims to provide a "treasure map" of solar energy with the help of Google Maps. Sunroof gives homeowners detailed information about how much solar power their roof can generate and how much money they could save on electricity costs by adding solar panels.

Sunroof uses data from Google Maps that previously had no practical application. For instance, Sunroof uses Maps’ 3D-modeling to calculate the amount of space a building’s roof has for solar panels. The service also analyzes the positioning of the sun over the course of a year, as well as the type of cloud cover and temperature the neighborhood usually experiences. It even considers the amount of shade cast by nearby objects.

Switching to solar energy can be a win-win scenario for many households. Harnessing a free power source can help save money on the electric bill while ever-so-slightly decreasing the world's dependance on greenhouse-gas-producing fossil fuels. But it's possible your home doesn't get enough sunlight, and it can be hard to know exactly how much money you'll save. Sunroof can tell users how many hours of usable sunlight they'll get a year, as well as how much available space they have for solar panels on their roof.

If a family decides those cost-saving benefits are good enough, Sunroof will suggest installers nearby who can load the panels. Installing solar panels isn't cheap, costing upwards of $20,000, but the average homeowner can save about $20,000 by switching to solar energy — if their home is in the right spot.

Right now, Project Sunroof is only available for people living in Boston, San Francisco, and Fresno, but Google plans to expand the service to the entire country.