The Federal Solar Tax Credit: Check It Before You Sign

The federal solar tax credit is finished. Not reduced, not phased down. Public Law 119-21, enacted 4 July 2025, amended 26 U.S.C. 25D at section 70506 so that the credit "shall not apply with respect to any expenditures made after December 31, 2025."

That single change rewrites the arithmetic in every solar proposal written before it. This page is the checklist that survives it: what the law says, the timing rule that will catch people who signed in 2025, and the four things that now decide whether an array is a good purchase. It is information rather than tax advice, and nothing here can tell you what your own return looks like.

What the statute says, and where the IRS says it

Section 25D is the Residential Clean Energy Credit — the 30% one that covered solar panels, batteries and geothermal. Its termination subsection now reads that the credit does not apply to expenditures made after 31 December 2025. The IRS carries the same limit on its own page for the credit, describes the 30% rate as applying to qualified property installed from 2022 through 31 December 2025, and published Fact Sheet FS-2025-05 on 21 August 2025 covering the accelerated terminations in the July law.

The companion credit ended on the same date by a separate section of the same act. Section 25C, the Energy Efficient Home Improvement Credit covering insulation, windows, skylights, doors and heat pumps, was terminated by section 70505 for any property placed in service after 31 December 2025. That matters here because the efficiency work that belongs ahead of any array was running on it.

One warning about checking this yourself. A search will still return confident pages saying the credit is available, and some of them are on irs.gov. Pages describing the rule for tax years that have closed are archived rather than removed, and they read as current because nothing on them announces otherwise. Read the date range inside the sentence, not the domain it arrived on.

The timing rule that catches people who signed in 2025

This is the part with actual victims, and it is the reason this section sits near the top.

The law does not ask when you paid. Section 25D(e)(8) treats an expenditure as made when the original installation of the item is completed, and the IRS guidance on the 2025 act applies that straight to the cutoff: where installation was completed after 31 December 2025, the expenditure counts as made after 31 December 2025.

So a deposit written in November against a system energized in March is on the wrong side of the line. So is a signed contract, a submitted permit, a paid-in-full invoice and an ordered pallet of panels. The only date that carries weight is the day installation was finished.

If that describes your project, two conversations are worth having in order. A tax professional first, because the answer depends on a return nobody selling panels has seen. Then the installer, with the contract open at whatever it says about incentives and about delay, because the savings case you agreed to was built around a number that is not going to arrive.

A credit was never a rebate

Anyone filing or amending for a year when the credit was live still needs this distinction. It caused more disappointment than any other feature of the credit while it existed.

A rebate is money sent to you. A credit reduces the federal income tax you owe. A household whose liability for the year came in under the credit did not capture all of it that year, and section 25D carried the unused portion forward rather than paying it out.

That carryforward is the one piece still moving. It belongs to expenditures already made, and it does nothing for a system installed now. If a salesperson subtracts a full federal credit from a price in front of you today, they are quoting a rule that no longer exists — which is a useful thing to learn about a company before you sign anything.

Every proposal written before 2026 needs re-running

A quote produced while the credit was alive had roughly 30% of the system price taken out of its payback calculation. Take that back out and the same array on the same roof pays for itself over a materially longer stretch of years.

That is not an argument against solar. It is an argument against carrying an old spreadsheet into a new decision.

Ask each bidder to produce their savings and payback estimate with no federal credit line in it at all, and to put it beside the version they first showed you. The gap between those two documents is the actual question in front of you, and a company that cannot generate the second one has told you something about how the first was assembled.

State and utility incentives are separate programs, set locally, and were not touched by the federal change. They are worth checking on their own terms — through your state energy office and your utility rather than through the installer's summary of them.

Compare in dollars per watt, before anything is subtracted

Here is the discipline that makes three quotes comparable, and it does more work now than it did when a credit was flattening the differences.

Ask each company for two things: the system size in kilowatts, and the gross price before any incentive at all. Divide the second by the size in watts. That price per watt is the number you rank.

A larger system costing more is not a worse deal, and a smaller one costing less is not a better one. Without normalizing by size you are comparing a total for one quantity of equipment against a total for another, which tells you nothing.

Do this before you look at monthly payments. A payment is the output of a financing decision, and a long enough term makes almost any price look manageable.

What exported power is worth now decides the payback

If you verify one thing on this list, make it this one. With the federal credit gone, the export tariff is the largest single variable left in the calculation.

Net metering and interconnection terms decide what a kilowatt hour is worth when your array produces it and the house is not using it. Under full retail net metering that exported unit offsets a unit you would otherwise buy. Under a thin export rate it is worth a fraction of that.

Same panels, same roof, same installer, completely different payback. These rules come from state regulators and utilities, which means the arithmetic in a national sales presentation may have nothing to do with your address.

Ask the utility directly, in writing. Which tariff applies, whether it is locked for a term, and what happens to existing customers when the tariff changes. Then ask the installer to rebuild their production and savings estimate on that tariff rather than a generic one.

Size the system to your bills, not to the roof

Pull twelve months of electricity bills and total the kilowatt hours. That number, not the available roof area, is where sizing starts.

A system built well past your consumption produces power you may be credited very little for, depending on the answer to the previous section. Oversizing is the most common way for a project's price to grow without its payback improving, and it was easier to hide while a percentage credit made a bigger system look proportionally cheaper.

Ask for the production estimate and the shading analysis behind it, then compare estimates across bidders for the same roof. Where one company's projection sits far above the others, that gap is information about the company rather than about your roof.

Replace the roof first

Mounting panels over a roof covering near the end of its service life creates a bill nobody plans for. When the roof is replaced, the array comes off and goes back on, and that removal and reinstallation is a real line item landing a few years after everyone thought the project was done.

Do the roof, then the array, even where that delays things by a season. It is one of the few sequencing questions in home improvement with an answer that is not debatable, and our roof replacement cost guide covers how to tell where a covering actually stands.

While the array is being designed, ask where the penetrations go, how they are flashed, and whose warranty covers a leak at a mount. That last question has a habit of producing a pause.

Read the financing harder than the equipment

Cash, a loan, a lease and a power purchase agreement are four different products with four different risk profiles, and only the first two leave you owning the system.

On a loan, find the dealer fee built into the price — it is usually why a cash price and a financed price differ. Then read the amortization. A great many solar loans were written on the assumption that the borrower would drop a large voluntary payment against the principal within the first eighteen months, funded by a federal credit. Where that structure is still in a contract being offered now, the payment steps up at the end of that window and there is nothing to cover it.

On leases and power purchase agreements, the two clauses that cause regret are the annual payment escalator and the transfer terms when you sell the house. A buyer who does not want to assume the agreement becomes a problem you inherit at the closing table.

When to skip it

Four situations turn a good product into a poor purchase, and none of them is a criticism of solar.

A heavily shaded roof will not carry a payback, and optimizers reduce that penalty rather than removing it. A short remaining stay in the house means somebody else collects savings you paid for. A utility that pays very little for exports stretches the payback past the point most people care about. And a roof with only a few years in it turns a finished project into a future removal and reinstall.

Where none of those applies, and the export tariff is favorable, solar is still one of the more straightforward purchases on this site — bought now on its own economics rather than on a subsidy. The full set of variables, including how to read a production estimate, is in our solar panel installation cost guide.

And if the goal is a lower bill rather than an array specifically, the cheap work comes first: air sealing, insulation, and the equipment that runs the most hours. That order was correct while both credits existed. With neither of them left to distort the comparison, it is simply the arithmetic.