How Solar Tax Credit Carryforward Still Works, Even After the Credit Itself Expired

Here's a detail that's easy to miss in all the coverage of the federal solar credit's 2025 expiration: if you installed before the cutoff, the credit isn't gone for you — it just isn't available for anyone installing after the cutoff. If your credit was larger than your tax bill in the year you installed, the unused portion still carries forward to future tax years exactly as it always did. The repeal changed who's eligible for new installations; it didn't touch the carryforward mechanism itself for people who already qualified.

That said, "carries forward" is a rule a lot of people file away and forget to actually apply correctly two or three years later. Here's how the math works in practice.

The mechanism, in plain terms

The Residential Clean Energy Credit is nonrefundable: it can reduce your federal tax liability to zero, but it won't generate a refund beyond what you owe. Any amount of the credit you can't use in the year you installed carries forward — with no expiration on the carryforward itself — until it's fully used against future tax liability.

This was true before the 2025 law change and remains true after it. What changed is only the window during which new installations can generate a fresh credit in the first place.

A worked multi-year example

The situation: A household installed a $32,000 solar-plus-battery system in September 2025, generating a $9,600 credit (30% of $32,000). Their federal tax liability varies year to year based on income, other credits, and deductions.

| Tax year | Federal tax liability (before this credit) | Credit available (including carryforward) | Credit used | Remaining carryforward | |---|---|---|---|---| | 2025 | $4,100 | $9,600 | $4,100 | $5,500 | | 2026 | $3,800 | $5,500 | $3,800 | $1,700 | | 2027 | $2,900 | $1,700 | $1,700 | $0 |

Across three tax years, this household used the full $9,600 credit, even though their tax liability in any single year never came close to that amount. Had they assumed the credit "expired" after one year of not using all of it, they'd have left over $1,700 unclaimed.

Why this matters more than usual right now

Because the credit no longer exists for new 2026+ installations, there's a real risk of confusion: some taxpayers who installed in 2025 might assume that because "the solar credit is gone," their own remaining carryforward balance is gone too. It isn't. The distinction that matters is:

| | Still true after the 2026 repeal? | |---|---| | New 2026+ installations generate a fresh 30% credit | No | | A credit already earned from a pre-2026 installation can carry forward | Yes | | There's a time limit on how long you can carry forward an unused balance | No — it carries forward until fully used, as under prior law | | You need to keep re-filing Form 5695 each year you carry forward a balance | Yes — the carryforward amount must be tracked and re-entered each tax year until exhausted |

A mistake that costs real money: not tracking the carryforward line

Form 5695's carryforward line only works if you (or your preparer) correctly carry the unused amount from the prior year's return into the current year's filing. If you switch tax preparers, switch software, or simply forget between tax seasons, it's genuinely easy to lose track of a five-figure credit balance sitting unclaimed. Keep a copy of every year's Form 5695 and the specific carryforward figure until the full credit is used up — this is one of the more common ways families with larger installations accidentally leave money on the table.

FAQ

Does the carryforward amount expire if I don't use it within a certain number of years? No — under current law, there's no statutory limit on how many years you can carry forward an unused Residential Clean Energy Credit balance. It carries forward until it's fully absorbed by tax liability in a future year.

What if I sell my home before using up the full carryforward? The carryforward credit belongs to you as the taxpayer who made the qualifying expenditure, not to the property — selling the home doesn't transfer or forfeit your remaining credit, but consult a tax professional about how a sale interacts with your specific filing situation.

Can I still amend a prior return if I realize I mis-tracked my carryforward amount? Generally yes, within the standard IRS statute of limitations for amended returns (typically three years from filing), you can file an amended return to correct a carryforward figure. Talk to a tax professional about your specific timeline before assuming you're out of options.

Does this carryforward rule apply to the Energy Efficient Home Improvement Credit (heat pumps, insulation) too? No — that credit works differently and generally does not carry forward unused amounts; it's structured as an annual credit rather than one with a carryforward mechanism. Our efficiency credit guide covers that distinction.

Fact-checked by Priya Nadar, P.E. This article explains general tax rules and is not personalized tax advice — consult a tax professional for your specific situation. Found an error? See our Corrections Policy.