Federal solar incentives: what depends on your installation date

Last reviewed 20 August 2026 · not tax advice

What changed

From 2022 the Residential Clean Energy Credit (Internal Revenue Code §25D) returned 30% of the cost of a qualifying residential solar system as a credit against federal income tax, with no dollar cap. It was originally legislated to taper through the early 2030s. The One Big Beautiful Bill Act (P.L. 119-21) ended it early: the credit is not available for expenditures made after 31 December 2025.

The word doing the work there is expenditure. For §25D, an expenditure on a solar electric system is generally treated as made when the original installation is completed — not when the contract was signed and not when the money left your account. A system paid for in full in 2025 but energised in 2026 therefore falls the wrong side of the line. If that describes your situation, it is a question for a tax professional and for the IRS, not for a website.

What it does to the arithmetic

The credit was worth 30% of gross system cost, so removing it raises net cost by roughly 43% of what you would previously have paid — and payback stretches by about the same proportion, because the annual saving is unchanged. In practice that has moved typical US payback from roughly 7–12 years to roughly 10–16, with the spread driven by your electricity rate far more than by sunshine.

Two consequences worth internalising before you shop. First, your electricity rate now dominates: in a high-rate state the loss of the credit is absorbed within a few years, while in a cheap-power state it can push payback past the point most households care about. Second, state and utility programmes matter far more than they used to — in several states they are now the single largest reduction available.

What still applies

• State income-tax credits — for example Arizona's 25% credit capped at $1,000, New York's 25% capped at $5,000, and Massachusetts' 15% capped at $1,000. Each has its own rules and its own cap.
• Performance and certificate programmes — SREC markets and production incentives such as Massachusetts' SMART, Illinois Shines and New Jersey's SREC-II pay per unit generated, over years, rather than as an upfront discount.
• Utility and state rebates — usually capped, often block-allocated, and frequently oversubscribed. Confirm availability before counting one.
• Sales-tax exemptions and property-tax exclusions — quieter, but common, and worth real money on a five-figure purchase.
• Third-party ownership — a lease or PPA is not your expenditure, so §25D never applied to it in the first place. Different federal provisions govern the owner, and whether any of that value reaches your monthly payment is a matter of the contract you sign.

The state guides name the programme and the regulator for each state we cover, with a review date on every page.

What to do with a quote that still includes the expired 30% credit

1. Ask the installer to reissue it with the federal line at zero, and compare the net figure to what you were shown.
2. Ask which state or utility programmes they have applied, and which are assumed rather than confirmed.
3. Ask for the installed cost per watt before incentives — that is the number that lets you compare quotes at all.
4. Take the corrected net cost back to the calculator and put it in as your installed cost.

Primary source: IRS — Residential Clean Energy Credit. Statutory change: One Big Beautiful Bill Act, P.L. 119-21. Last reviewed 20 August 2026 by SolarDime editorial. This page is general information, not tax advice; your eligibility depends on facts only you and your tax preparer have.