For personal residence only solar improvements apply for the current year:
As of the 2017 tax year, the federal government offers two such credits: the Residential Energy Efficiency Property Credit and the Nonbusiness Energy Property Credit. The credits are good through 2016, except for the solar credits which are good through 2019 and then are reduced each year through the end of 2021
Please click the Energy Tax Credits FAQ updated for 2017.
