Geothermal Tax Credit 2025: Form 5695 and the Oct 15 Deadline

This article serves two readers, and it will be blunt with both.

If you installed a geothermal heat pump in 2025 and you're sitting on a 2025 tax return (filed in April or on an extension), this is your filing guide. The 30% Residential Clean Energy Credit (Section 25D) is still claimable for systems placed in service by December 31, 2025, you claim it on Form 5695, and any unused portion carries forward. If you filed Form 4868 for an extension, your deadline is October 15, 2026.

If you're a 2026 searcher wondering whether the credit still exists: it doesn't. For property placed in service after December 31, 2025, there is no 30% residential geothermal credit. We'll say that plainly, show you where the IRS says it, and point you at what exists in 2026.

The Short Version

If you're in a hurry, here's the whole article in five bullets:

• The 30% credit is real for 2025 installs and dead for 2026 installs. Section 25D applies to property placed in service from 2022 through December 31, 2025, and it is "not available for any property placed in service after December 31, 2025."
• Completion, not payment, is what counts. A system had to be fully installed and operational by December 31, 2025. Paying in full in 2025 doesn't save a system finished in January 2026.
• You claim it on Form 5695, Part I, with your 2025 return, on a dedicated line for qualified geothermal heat pump property costs.
• The credit is nonrefundable but carries forward indefinitely. If your tax liability is smaller than the credit, the unused portion rolls to 2026 and beyond. The 2025 instructions are explicit: "File this form even if you can't use any of your credit in 2025."
• Extension filers have until October 15, 2026. The extension is for filing only. Any tax you owed was due April 15, 2026.

Everything below is sourced from IRS forms, instructions, and a Congressional Research Service report. The full list is at the bottom.

The Credit Is Dead for 2026 Installs

Let's get the uncomfortable part out of the way, because half the people who land on this page are looking for a 2026 tax credit and the honest answer is no.

The One Big Beautiful Bill Act (Public Law 119-21), signed July 4, 2025, repealed the residential clean energy credit for expenditures made after calendar year 2025. The IRS's own Residential Clean Energy Credit page states the operative rule in two sentences:

"The Residential Clean Energy Credit equals 30% of the costs of new, qualified clean energy property for your home installed anytime from 2022 through December 31, 2025. The credit is not available for any property placed in service after December 31, 2025."

IRS, Residential Clean Energy Credit

The 2025 Form 5695 instructions say the same in their "What's New" section: "You can't claim residential clean energy credits for expenditures made after December 31, 2025."

One housekeeping note: the IRS's Residential Clean Energy Credit page still carries a leftover Inflation Reduction Act sentence saying the credit runs "until the credit begins to phase out in 2033." That sentence contradicts the page's own termination statement and every other primary source. The December 31, 2025 termination is the operative rule. If a blog or a sales pitch tells you the credit phases out in 2033, that person is reading a stale sentence on a live page.

Our news coverage of the 2026 policy state has the full timeline. This article assumes the premise (the credit is gone for new installs) and focuses on the people who still have a claim: the 2025 installers.

Who Can Still Claim: The Placed-in-Service Rule

Here's the rule that decides whether you have a claim at all, and it's the one people get wrong.

The credit attaches to when the original installation is completed, not when you pay. The IRS FAQ on the OBBB credit modifications answers this directly:

"For purposes of the residential clean energy credit under section 25D, can a credit be claimed for property installed after December 31, 2025, or constructed after that date, if a taxpayer pays for the property on or before December 31, 2025? No. Section 25D(e)(8)(A) provides that an expenditure with respect to an item is treated as made when the original installation of the item is completed. If installation is completed after December 31, 2025, the expenditure will be treated as made after December 31, 2025, which will prevent the taxpayer from claiming the section 25D credit."

IRS, FAQs for the modification of sections 25C, 25D, and related credits under Public Law 119-21

So the test is: was your system fully installed and operational by December 31, 2025? If yes, you have a 2025 claim. If the loop was drilled in November but the heat pump wasn't set and commissioned until January, you don't. No amount of 2025 paperwork changes that. A deposit, or even full payment, made in 2025 does not qualify a system completed in 2026.

For homes under construction or reconstruction, the expenditure is treated as made "when the original use of the constructed or reconstructed structure by the taxpayer begins." In practice, that's the year you move in and start using the home, not the year the contractor finished the mechanicals.

A few other eligibility details from the IRS's credit page:

• Where: a home in the United States, either your main home or a second home. Not rental or landlord property.
• New or existing home: both qualify.
• What counts as cost: the equipment plus labor for onsite preparation, assembly, and original installation. For geothermal, that's the heat pump, the loop, the drilling or trenching, and the install labor.
• Efficiency: geothermal heat pumps must meet the Energy Star requirements in effect at the time of purchase. Keep your installer's documentation showing the unit's Energy Star status.
• No dollar cap: no annual or lifetime limit (the only caps in the section apply to fuel cells). A $50,000 system generates a $15,000 credit just as cleanly as a $20,000 system generates $6,000.

If you're reconstructing your cost basis for the return, our installation cost guide breaks down what typically goes into a geothermal bill, useful for making sure your Form 5695 number matches your invoice.

How to Claim It: Form 5695, Part I

The mechanics are simpler than the policy is. One form, one part, one line.

You claim the credit on IRS Form 5695, Residential Energy Credits, which attaches to Form 1040, 1040-SR, or 1040-NR. The form has two parts, and keeping them straight matters:

• Part I, Residential Clean Energy Credit (Section 25D). This is where your geothermal claim lives, on a dedicated line for "Qualified geothermal heat pump property costs."
• Part II, Energy Efficient Home Improvement Credit (Section 25C). A different credit with different rules: windows, doors, certain heat pumps, insulation. If you also claimed 25C items in 2025, they go here (more in the mistakes section).

The 2025 instructions define what qualifies:

"Qualified geothermal heat pump property is any equipment that uses the ground or ground water as a thermal energy source to heat your home or as a thermal energy sink to cool your home. To qualify for the credit, the geothermal heat pump property must meet the requirements of the Energy Star program that are in effect at the time of purchase. The home doesn't have to be your main home."

IRS, Instructions for Form 5695 (2025)

Three practical points for the actual filing:

1. Claim it in the year the property was installed, not the year you bought it. The IRS credit page is explicit: "You must claim the credit for the tax year when the property is installed, not merely purchased." For a system placed in service in 2025, that's your 2025 return, even if you file it in October 2026 on extension.

2. Part I is also where carryforwards get claimed. The form's header note tells you to "skip lines 1 through 11 if you only have a credit carryforward from 2024." Fresh 2025 credit or prior-year carryforward, the destination is the same: Part I.

3. Keep the paperwork. Your invoice, the installer's documentation of the Energy Star-compliant unit, and proof of the completion date are your evidence if the credit is ever examined. The form itself doesn't ask for them.

The October 15, 2026 Deadline

Now the calendar, because it's where people actually lose money.

The 2025 return was originally due April 15, 2026, per IRS Tax Topic 301. If you filed by then, this section is a reassurance: your Form 5695 is already in the system.

If you didn't file, the question is whether you filed Form 4868, the automatic six-month extension, by the original April 15, 2026 due date. If you did, the IRS's extension page is unambiguous: "This gives you until October 15 to file without penalties." A homeowner who filed Form 4868 by April 15, 2026 has until October 15, 2026 to file the 2025 return, and Form 5695 claims the geothermal credit on that extended return.

Two things the extension does not do, both stated on the IRS's own extension page:

• It doesn't extend the payment deadline. "Make sure you pay any tax you owe by the April filing date. The extension is only for filing your return." Tax owed was due April 15, 2026, and interest accrues on unpaid amounts from that date.
• It doesn't extend the credit's eligibility. The placed-in-service cutoff was December 31, 2025, and no filing extension changes that.

If you neither filed nor filed Form 4868 by April 15, 2026, you're past the automatic-extension window. That's a conversation for a tax professional, since penalties and interest are now in the picture. Don't let that stop you from filing the return with the credit on it. A late return with a $9,000 credit beats no return at all.

Carryforward: Banking Credit You Can't Use Yet

This is the part of the story that surprises people, and it's the reason the credit was worth more than your tax bill suggested.

The 25D credit is nonrefundable: in any given year, it can't reduce your tax below zero. Owe $7,000 in tax with a $9,000 credit, and you can only use $7,000 of it this year. Most credits would throw the remaining $2,000 away. Section 25D doesn't.

The IRS credit page: "The credit is nonrefundable, so the credit amount you receive can't exceed the amount you owe in tax. You can carry forward any excess unused credit, though, and apply it to reduce the tax you owe in future years."

The 2025 Form 5695 instructions, at line 16, give the filing instruction that matters most:

"If you can't use all of the credit because of the tax liability limit (that is, line 14 is less than line 13), you can carry the unused portion of the credit to 2026. File this form even if you can't use any of your credit in 2025."

IRS, Instructions for Form 5695 (2025)

Read that last sentence again if it passed by. A homeowner who owes less tax than the credit, or even zero tax, still has to file Form 5695. The carryforward is created by the filing. Skip the form and the unused credit doesn't quietly bank itself.

How long does the carryforward last? The Congressional Research Service's report on the credit's expiration (IN12611, September 25, 2025) is direct: "Carryforwards may be utilized indefinitely until a taxpayer has used the entire credit amount." Year to year, against whatever tax you owe, until it's used up. And the credit's expiration didn't touch this right. CRS states that "taxpayers who make qualifying expenditures before the end of 2025 may carry forward any unused RCEC amounts to future tax years," even though no new expenditures qualify after 2025.

And this isn't a theoretical edge case. CRS cites preliminary IRS data for tax year 2023: nearly 1.4 million taxpayers qualified for the credit, and roughly half carried forward part or all of it: 601,000 (43.3%) carried forward part of their credits and 142,000 (10.2%) carried forward their entire credits. If you have a big geothermal credit and a modest tax bill, you're in the majority, not the exception.

Two Mistakes 25D Filers Make

Both come from confusing Section 25D (your geothermal credit, Part I) with Section 25C (the energy-efficient home improvement credit, Part II). The two credits share a form, which is exactly the problem.

Mistake one: hunting for a QMID you don't need. Starting in 2025, Section 25C claims for "specified property" require a Qualified Manufacturer Identification Number (QMID) for each item. The IRS's 25C page and the Form 5695 instructions both say so, and the requirement attaches to Part II. No such requirement applies to geothermal heat pumps claimed under Section 25D in Part I: neither the 25D statute, the 2025 Form 5695 instructions, nor the Part I lines impose a QMID or QMIN on geothermal claims. If a third-party article tells you your geothermal credit is at risk because you can't find a QMID, it's describing the other credit. (If you also claimed 25C items on Part II, like a conventional air-source heat pump or windows, QMID applies to those items, not your geothermal line.)

Mistake two: assuming the carryforward works both ways. It doesn't. Section 25D carries forward indefinitely. Section 25C does not. The IRS's 25C page is blunt: "The credit is nonrefundable, so you can't get back more on the credit than you owe in taxes. You can't apply any excess credit to future tax years." The Form 5695 itself reflects the difference: Part I has carryforward lines, while Part II has a year-specific limit worksheet and no carryforward line. A 2025 geothermal install that exceeds your tax liability banks the excess for future years. A 2025 air-source heat pump claim that exceeds its limits is simply lost. Same form, opposite fates.

What Exists for 2026 Installs

For completeness, and for the 2026 searcher who came here hoping: there is no homeowner federal tax credit for geothermal installed in 2026. Section 25D is gone for post-2025 expenditures, full stop.

The federal money that remains in 2026 lives on the business side. Section 48E, the Clean Electricity Investment Credit, is a business credit claimed by the owner of qualifying facilities and energy storage technology. The IRS's own 48E page describes it in terms of zero-GHG electricity facilities and storage, without mentioning residential geothermal heat pumps. A homeowner touches that world only through third-party ownership: a developer or utility that owns the equipment and claims the business credit itself. That's a financing structure, not a tax credit you file. Our financing options comparison covers the trade-offs.

Otherwise, what's left in 2026 is state programs and utility rebates, which vary by state and utility and don't depend on the federal credit. If you're deciding whether geothermal still makes financial sense without the 30% credit, our is-geothermal-worth-it analysis walks through the math with the credit out of the picture.

Frequently Asked Questions

I paid for my system in 2025, but it was finished in January 2026. Do I get the credit?

No. An expenditure is treated as made "when the original installation of the item is completed." If installation completed after December 31, 2025, the credit isn't available. It doesn't matter when you paid. Completion date controls, not payment date.

I owe less tax than my credit. Do I lose the difference?

No. The 25D credit is nonrefundable in a single year, but the unused portion carries forward to future years indefinitely. The 2025 Form 5695 instructions say to carry the unused portion to 2026, and to file the form "even if you can't use any of your credit in 2025." Filing is what creates the carryforward.

How long can I carry the credit forward?

Indefinitely. CRS states that "carryforwards may be utilized indefinitely until a taxpayer has used the entire credit amount," and the credit's 2025 expiration did not change the carryforward rules. Taxpayers with qualifying 2025 expenditures may carry unused amounts to future tax years.

Do I need a QMID or QMIN for my geothermal claim?

No. The QMID requirement applies to Section 25C "specified property" claimed on Part II of Form 5695, not to geothermal heat pumps claimed under Section 25D on Part I. Nothing in the 25D statute, the 2025 Form 5695 instructions, or the Part I lines requires a manufacturer identification number for geothermal.

I installed in 2026. Is there any federal credit at all?

No homeowner federal credit. Section 25D is not available for property placed in service after December 31, 2025. Federal clean-energy money in 2026 exists on the business side (Section 48E), which a homeowner reaches only through third-party ownership arrangements. Your 2026 incentives are state programs and utility rebates.