Google has just launched its latest online tool, Project Sunroof, to map the planet’s solar potential of planet, one rooftop at a time. Project Sunroof uses information from Google Maps, and takes into account everything from the angle of the roof, the weather, and obstructions like trees and chimneys, to tell users how many solar panels they would need for their structure and how much money one could save on electric bill by way of solar power. Users can then see how buying or leasing panels affects savings, and then send an estimate to local installers, instantly. Project Sunroof is currently limited to Boston, the San Francisco Bay Area, and Fresno, so if you live in one of these areas, you can proceed to google.com/sunroof to enter your address and figure out how much solar energy could save you. Anyone can also sign up via the website to be notified when Project Sunroof expands to their local neighborhood.