In what may be the greatest idea since sliced bread, the Google Sunroof program will let viewers see exactly how much sunlight strikes their roof every year and calculate how much they could save with rooftop solar panels. Once you put in your address, you will be told how much you are likely to save in energy costs and be put in touch with a local installer.

Google Maps already has satellite, navigation, and sunlight data for every property in the world, so it knows how much sunlight hits a roof on a daily basis. The program will begin in Boston, San Francisco, and Fresno and could spread like sunlight at dawn to every rooftop in the world. Wow!

Sunroof is intended as a “treasure map” for future green energy projects, telling you how much of a saving you’d make and how long it will take to make back your initial investment.

The folks at Engadget tested the service on the AOL building in San Francisco. Sunroof said the roof received 1,840 hours of usable sunlight per year and calculated that about 15,641 square feet were available to install solar panels. Next, it evaluated the options and reported that AOL could save $14,000 if it leased the hardware, or $24,000 if it bought a system outright.

Imagine the possibilities. No more contacting a bunch of different solar installers and waiting months for someone to come inspect your roof to tell you whether a rooftop solar system would be right for you. Now you can do all that from the comfort of your living room using your own computer. Google will calculate your savings for you automatically.

Sunroof will also let you know if your rooftop is not a suitable candidate for solar, which applies to perhaps half of all roofs around the world. Some face the wrong way, some have too much shade, and some have the wrong pitch to be effective.

Information is power, so they say. Now, information can tell you quickly and easily how much power you can generate using your very own roof. Google Sunroof could revolutionize the home solar industry.