Are you referring to part of the Solar credit, or part of the $500 credit? This is in regards to the $500 non-business credit:
Qualified energy efficiency improvements are the following building envelope components installed on or in your main home that you owned during 2020 located in the United States if the original use of the component begins with you, the component can be expected to remain in use at least 5 years, and the component meets certain energy standards.
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.
Exterior windows and skylights.
Any metal roof with appropriate pigmented coatings or asphalt roof with appropriate cooling granules that are specifically and primarily designed to reduce the heat gain of your home.
For purposes of figuring the credit, don't include amounts paid for the onsite preparation, assembly, or original installation of the building envelope component.
To qualify for the credit, qualified energy efficiency improvements must meet certain energy efficiency requirements. See Lines 19a Through 19h, later, for details.