The term “construction” includes substantial reconstruction and rehabilitation.
The term “acquire” includes purchase.
A certification described in subsection (c) shall be made in accordance with guidance prescribed by the Secretary, after consultation with the Secretary of Energy. Such guidance shall specify procedures and methods for calculating energy and cost savings.
Any certification described in subsection (c) shall be made in writing in a manner which specifies in readily verifiable fashion the energy efficient building envelope components and energy efficient heating or cooling equipment installed and their respective rated energy efficiency performance.
For purposes of this subtitle, if a credit is allowed under this section in connection with any expenditure for any property, the increase in the basis of such property which would (but for this subsection) result from such expenditure shall be reduced by the amount of the credit so determined.
This section shall not apply to any qualified new energy efficient home acquired after December 31, 2020.