Thank your congressman or senator for extending the program through 2021. Download the simple 2 page form here: Federal Solar Tax Credit Form 2017 .
Congress established the Energy Policy Act of 2005 which allows homeowners and businesses to receive 26% of the cost of a new solar electric, solar water heating, wind energy, and geothermal systems back on their taxes. This helped establish new technologies and has created a major financial incentive for homeowners to go solar. The initial program was extended twice but now steps down the incentive amounts starting in 2020.
Established by The Energy Policy Act of 2005, the federal tax credit for residential energy property initially applied to solar-electric systems, solar water heating systems and fuel cells. The Energy Improvement and Extension Act of 2008 extended the tax credit to small wind-energy systems and geothermal heat pumps, effective January 1, 2008. Other key revisions included an eight-year extension of the credit to December 31, 2016; the ability to take the credit against the alternative minimum tax; and the removal of the $2,000 credit limit for solar-electric systems beginning in 2009. The credit was further enhanced in February 2009 by The American Recovery and Reinvestment Act of 2009, which removed the maximum credit amount for all eligible technologies (except fuel cells) placed in service after 2008.
More details available here: Link to Solar Tax Credit info