If you're eligible for the solar tax credit, yes, the installation costs are included.
Sec. 25D provides a solar tax credit to an individual taxpayer when
the panels are installed for use in the taxpayer's residence. Under
Secs. 25D(d)(1) and (2), solar water-heating panels and solar electric
(photovoltaic) panels must be installed for use in a dwelling located in
the United States and used as a residence by the taxpayer. Thus, Sec.
25D does not allow a credit when solar panels are installed for use in a
residential rental property the taxpayer owns.
In Notice 2013-70, which provides guidance on Sec. 25D, the IRS
further clarified this issue. Question 6 in the notice asks whether the
credit is available for improvements made to a second home, for example,
a vacation home or an investment property. In its answer, the IRS
specifically states that while the credit may be taken for solar panels
installed for use in a vacation home, the taxpayer may not claim the
Sec. 25D credit for expenditures for improvements made to an investment
property, such as rental property, that is not also used as a residence
by the taxpayer.
https://turbotax.intuit.com/tax-tips/going-green/federal-tax-credit-for-solar-energy/L7s9ZiB4D
[Edited] For rental/investment property, instead of the solar credit you may be eligible to take an Investment Credit (IRS Form 3468). See page 4 of this IRS reference: https://www.irs.gov/pub/irs-pdf/i3468.pdf
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
