The credit was retroactively implemented for 2017 in the Bipartisan Budget Act of 2018, signed into law in February 2018. Check the instructions for the Federal Form 5695. Part II of the form now covers qualified energy efficiency improvements. It's *possible* that solar sunscreens meet the definition of "Any insulation material or system that is specifically and primarily designed to reduce heat loss or gain of a home when installed in or on such a home."
