You may possibly be able to claim the Residential Clean Energy Credit, as this is available for both new and existing homes. In order to claim the credit, you must be living in the home and the fixture you are claiming must be operable. It does not matter if a contractor is installing it or if you are installing it yourself, you can still claim the credit as long as it meets the criteria to claim the credit.
Since you are still building your home, if the items were not in use or you were not living there by December 31, 2024, you would not be able to claim the credit on your 2024 return. You would need to wait until you move into the home and are using the energy products.