The news is especially good for homeowners, many of whom still view solar as beyond their financial reach or as a resource still unproven. Costs for home solar systems continue to plummet. Since the solar and wind Investment Tax Credit (ITC) was implemented in 2006, the cost of installing solar has dropped by more than 73 percent, according to the Solar Energy Industries Association. And the 30 percent tax credit for solar under the ITC, set to expire at the end of 2015, has been extended by Congress for an additional three years, followed by a two-year ramp-down period.