Google can tell you if solar roof panels will pay off

Google has got a good look at your roof, and can tell you if it is worth the investment to install solar energy panels. The new tool "uses high-resolution aerial mapping (the same used by Google Earth) to help you calculate your roof's solar energy potential, without having to climb up any ladders," Google engineer Carl Elkin said in a blog post.

http://phys.org/news/2015-08-google-solar-roof-panels.html