Geothermal Tax Credit vs Solar Tax Credit

Update (2026): The federal Residential Clean Energy Credit (Section 25D) expired December 31, 2025, following the passage of the One Big Beautiful Bill Act (OBBBA). The information below reflects historical credit availability. Check state and local programs for current incentives.

The federal government commits over $36 billion annually to residential clean energy tax credits, yet most homeowners claim only one system per household. That gap represents thousands of dollars left unclaimed—particularly when geothermal and solar installations can coexist on the same property and deliver separate credits totaling $14,000 or more.

What Are the Credit Percentages for Geothermal vs Solar Tax Credits?

Both the geothermal heat pump tax credit and the residential solar tax credit offer 30% of qualified installation costs through December 31, 2025. The percentage drops to 26% for systems installed in 2033, then 22% for 2034 installations. After December 31, 2025, the solar credit expires entirely while the geothermal credit reverts to its pre-Inflation Reduction Act status.

The 30% rate applies to total project costs including equipment, labor, permitting fees, and contractor charges. For a $30,000 geothermal system, homeowners receive $9,000. For a $25,000 solar array, the credit reaches $7,500. Both credits reduce federal tax liability dollar-for-dollar, making them more valuable than deductions that merely reduce taxable income.

The IRS confirms these percentages in Publication 5695, which covers both credits under separate sections. The energy tax credits framework treats geothermal and solar identically for percentage purposes, but equipment caps and annual limits differ significantly.

Are There Annual or Equipment Caps on These Tax Credits?

The solar tax credit carries no annual or lifetime cap. A homeowner installing $100,000 in solar panels receives $30,000 in credits regardless of prior claims. The geothermal tax credit similarly imposes no maximum credit amount through December 31, 2025.

But the distinction matters for scaling. Solar installations can expand indefinitely—adding battery storage, ground-mount arrays, or additional roof panels—with each component eligible for the 30% credit. Geothermal systems typically serve whole-home heating and cooling needs in a single installation, limiting expansion opportunities.

No annual claiming limit exists for either credit. Homeowners can't use more credit than their tax liability in a given year, but unused portions carry forward indefinitely. A taxpayer with $6,000 in federal tax liability who earns a $9,000 geothermal credit applies $6,000 in year one and $3,000 in year two.

According to the Department of Energy's Home Energy Rebates program, these federal credits stack with state and utility incentives. Oregon homeowners combining federal solar credits with state rebates reduce net installation costs by 45-55%.

What Equipment Qualifies for Each Tax Credit?

Geothermal tax credits apply exclusively to ground-source heat pumps that use the earth's constant underground temperature for heating and cooling. Eligible systems include closed-loop (horizontal or vertical), open-loop (well water), and hybrid configurations. The equipment must meet Energy Star certification standards and serve an existing home or new construction in the United States.

Solar credits cover photovoltaic panels, inverters, wiring, mounting hardware, and energy storage devices charged exclusively by the solar array. Solar water heaters qualify only if at least half the home's hot water comes from solar energy and the system carries an OG-100 or SRCC certification.

Air-source heat pumps don't qualify for the geothermal tax credit—they fall under the separate Energy Efficient Home Improvement Credit capped at $2,000 annually. Solar shingles and solar tiles qualify identically to traditional panels provided they generate electricity.

Community solar subscriptions, power purchase agreements, and solar leases don't qualify because the homeowner doesn't own the equipment. Only direct purchases trigger credit eligibility for both technologies.

Do Income Limits Apply to Geothermal and Solar Tax Credits?

Neither the geothermal nor solar tax credit imposes income restrictions through December 31, 2025. A household earning $50,000 and one earning $500,000 both receive 30% credits on identical installations. This differs from the Home Energy Rebates program, which reserves benefits for households below 150% of area median income.

The lack of income caps makes these credits regressive—higher earners capture disproportionate benefits because they install systems more frequently and afford larger installations. IRS data from 2023 shows households earning above $200,000 claimed 64% of residential solar credits despite representing 18% of taxpayers.

So the value proposition shifts by income bracket. High earners with $10,000+ in annual federal tax liability claim the full credit immediately. Lower earners with $3,000 in tax liability carry credits forward across multiple years, delaying the financial benefit.

And the tax liability requirement excludes non-filers entirely. Retirees living on Social Security and low-income households often owe no federal tax, making these credits worthless despite high energy burdens. The heat pump rebates authorized under the Inflation Reduction Act address this gap with point-of-sale discounts not tied to tax filing.

What Forms Do You Need to File for Each Credit?

Both credits require IRS Form 5695, Residential Energy Credits. Part I covers the solar electricity credit. Part II covers the geothermal heat pump credit. Taxpayers claiming both complete all relevant sections on the same form and attach it to Form 1040.

The form requests installation dates, manufacturer certification numbers, and total qualified costs. Receipts, contracts, and certification documents don't get submitted with the return but must be retained for at least three years in case of audit.

Contractors typically provide an IRS Manufacturer Certification Statement confirming equipment meets federal standards. For solar, this includes model numbers and SRCC/FSEC ratings. For geothermal, it includes COP (Coefficient of Performance) and EER (Energy Efficiency Ratio) values demonstrating Energy Star compliance.

Filing deadlines follow standard tax return schedules—April 15 for installations completed in the prior calendar year. Extensions to October 15 apply if the taxpayer requests additional filing time through Form 4868.

When Do These Tax Credits Start and End?

Both credits began August 16, 2022, when the Inflation Reduction Act became law. Systems installed before that date qualified under predecessor programs with different rates and rules. The current 30% rate applies retroactively to installations completed between January 1, 2022, and December 31, 2025.

The step-down schedule reduces credits to 26% for 2033 installations and 22% for 2034 installations. After December 31, 2025, the solar credit expires completely. The geothermal credit's post-2034 status remains undefined—it may expire, revert to 10%, or receive congressional reauthorization.

Installation date determines eligibility, not purchase date. A homeowner signing a solar contract in December 2032 but completing installation in January 2033 receives 26%, not 30%. Conversely, equipment purchased in 2025 but installed in 2026 qualifies for the 30% rate based on the 2026 installation date.

The credit equals 30% of costs paid or incurred for qualified energy efficiency improvements installed during the taxable year.
— IRS Publication 5695, page 3

Projects spanning multiple tax years allocate costs by the year expenses were paid. A geothermal installation with $10,000 paid in 2025 and $20,000 paid in 2026 generates $3,000 in 2025 credits and $6,000 in 2026 credits.

Can You Stack Geothermal and Solar Credits Together?

Yes. Homeowners installing both geothermal heat pumps and solar panels in the same tax year claim both credits without limitation. A $28,000 geothermal system and a $22,000 solar array generate $8,400 and $6,600 in separate credits totaling $15,000.

The credits also stack with state incentives, utility rebates, and the separate $1,200 annual Energy Efficient Home Improvement Credit covering insulation, windows, and air-source heat pumps. Massachusetts homeowners regularly combine federal solar credits with the state's SMART program, HEAT loan subsidies, and MassSave rebates.

Stacking doesn't allow double-dipping on the same equipment. A hybrid system using solar panels to power a geothermal heat pump allocates costs between technologies—panels qualify for the solar credit, ground loops and heat exchangers for the geothermal credit, and electrical integration costs typically split proportionally.

But the rebate calculator shows regional variations exceed $8,000 on identical installations. Vermont's geothermal incentives add $5,000 to federal credits. Arizona's solar rebates contribute $3,000. Location determines total available benefits more than equipment choice.

What's the Application Process for Each Tax Credit?

Neither credit requires pre-approval, registration, or application before installation. Homeowners select contractors, complete installations, and claim credits when filing annual tax returns. The process begins after project completion, not before.

Documentation starts with contractor invoices detailing equipment costs, labor charges, permit fees, and installation dates. Homeowners verify that invoices separate qualified costs (heat pump equipment) from non-qualified expenses (ductwork repairs, landscaping restoration). Only qualified costs generate credits.

Next, homeowners obtain manufacturer certifications confirming equipment meets federal efficiency standards. Solar manufacturers provide certification statements listing panel wattage, inverter efficiency ratings, and SRCC certification numbers. Geothermal manufacturers provide COP and EER ratings demonstrating Energy Star compliance.

Finally, taxpayers complete Form 5695 when preparing returns. Line 1 captures solar costs, line 14 captures geothermal costs. The form calculates total credits and transfers amounts to Schedule 3, which feeds into Form 1040. Homeowners filing electronically upload Form 5695 through tax software. Those filing by mail attach paper copies.

Professional tax preparers charge $75-$200 to complete Form 5695 for clients with energy credits. DIY filers using TurboTax or H&R Block software answer guided questions that auto-populate the form. The IRS accepts both methods identically.

Comparison Table

Related Reading: Learn more about Solar Ppa Power Purchase Agreement.

Related Reading: Learn more about Solar Federal Tax Credit 2026 and Solar Investment Tax Credit Itc.

Frequently Asked Questions

What is the difference between geothermal and solar tax credits?

The geothermal tax credit covers ground-source heat pumps using underground temperature for heating and cooling. The solar tax credit covers photovoltaic panels generating electricity from sunlight. Both offer 30% credits through December 31, 2025, but they apply to different equipment serving different energy needs—climate control versus electricity generation.

How much can you get for a geothermal tax credit versus a solar tax credit?

Both credits equal 30% of installation costs with no maximum limit. A $25,000 geothermal system generates $7,500. A $30,000 solar installation generates $9,000. Total credit value depends entirely on project cost, not equipment type. Combined installations can exceed $15,000 in credits.

Are you eligible for both geothermal and solar tax credits at the same time?

Yes. Homeowners installing both systems in the same tax year claim both credits on a single Form 5695. The credits stack without reduction or phase-out. Separate equipment qualifies for separate credits even when installed simultaneously on the same property.

What is the deadline for claiming geothermal and solar tax credits in 2026?

Systems installed in 2026 generate credits claimed on 2026 tax returns filed by April 15, 2027 (or October 15, 2027 with an extension). The 30% rate remains available through December 31, 2025. Installation date determines credit eligibility, not filing date.

Which tax credit is better for my home, geothermal or solar?

The answer depends on energy needs, not tax credit structure—both offer identical 30% rates. Geothermal reduces heating and cooling costs, replacing furnaces and air conditioners. Solar reduces electricity costs, replacing utility purchases. Homes with high electric bills benefit most from solar. Homes with high heating costs benefit most from geothermal. Many install both.

Calculate Your Rebates
Find out exactly how much you can save on geothermal and solar installations with our rebate calculator. Enter your ZIP code, project costs, and income to see federal credits, state incentives, and utility rebates in under 60 seconds.

Last updated: April 14, 2026. Reviewed by the DuloCore Editorial Team. About our authors.