i met with scientist and architect mike binder for an >> sunlight, really all light is a stream of microscopicic particles called photons an they strike the panel and at a microscopic level, when they hit the panel they break loose the electronics in the material from the rest of the material and that creates a flow of electrons which is in fact electric current and that current flows and that is what generates power that you can use in your toaster. >> reporter: here in the d.c., maryland and virginia area we get an average of 200 days of sunshine a year. that's pretty good and even during a mostly cloudy day, some energy is being collected. >> there are on-line tools, websites where you can go and see how much power your roof might produce. >> reporter: consumers should know roof of their roof they want to use for solar panels and how much they want to spend. from there an out and see what direction your house is facing and size the system for you. solar is cheaper than traditional power and homeowners can save a little bit of money saying the founder of ceo of neighborhood sun. here's today