Mapdwell Solarsystem is a tool that allows users to calculate the solar potential of their buildings. Currently the tool only has information for Washington DC and Cambridge, but there are plans to expand. When using the tool, users choose a building or an area and are returned with annual revenue, payback period, system size etc. The tool works using a slider that changes the size of the system and displays using a Google Map. This tool is somewhat similar to this one from a while back.