Question 1

Does PTO have to be received by December 31 for the 25D solar tax credit?

Accepted Answer

No. IRC §25D(e)(8) treats the expenditure as made when original installation is completed. Permission to operate is not that clock. A 2025 install-complete date still sits on the 2025 IRS clock if PTO arrives in January. A minority of Reddit audit anecdotes asked for PTO; that is not the statute. Cite IRS FS-2025-05.

Question 2

Does paying in full or signing a contract in 2025 lock the 30% credit if install is in 2026?

Accepted Answer

No. Contract, deposit, and invoice dates are not the 25D clock. Pay-in-full in 2025 does not save a 2026 install. If original installation is completed on or after 2026-01-01, the 2025 25D clock is dead. A 30% line still printed on a quote does not change that.

Question 3

Which date does the IRS use for the residential clean energy credit after OBBBA?

Accepted Answer

Installation completed. IRC §25D(e)(8) says the expenditure is treated as made when original installation of the item is completed. For a new dwelling, also see the original-use rule in §25D(e)(8)(B). Inspection is supporting evidence, not the clock. This is not tax advice.