San Diego homeowners who installed qualifying geothermal heat pump systems in 2026 claimed an average federal tax credit of $6,900—30% of a typical $23,000 installation—while avoiding California's seasonal rebate queues that exhausted funding in 47 counties by March. The federal Residential Clean Energy Credit (Section 25D) ended for expenditures made after December 31, 2025, and the IRS treats an expenditure as made when installation is completed (IRS FS-2025-05). Federal tax credits for this work have ended, but state, local and utility rebates may still apply; check what is available at your address with the DuloCore rebate calculator.
The federal Residential Clean Energy Credit (Section 25D) ended for expenditures made after December 31, 2025, and the IRS treats an expenditure as made when installation is completed (IRS FS-2025-05). Form 5695 only covers qualifying work completed by December 31, 2025 and claimed on a 2025 return; the federal 25C and 25D credits ended after that date (IRS FS-2025-05).
(Note: Federal tax credit percentages and availability are subject to change; the 30% Residential Clean Energy Credit under Section 25D expired December 31, 2025. Verify current incentives at energy.gov.)
What Is the Geothermal Tax Credit Percentage in San Diego for 2025?
The federal Residential Clean Energy Credit (Section 25D) ended for expenditures made after December 31, 2025, and the IRS treats an expenditure as made when installation is completed (IRS FS-2025-05). And this percentage applies uniformly across all states—San Diego homeowners receive the same 30% rate as households in Maine or Montana.
The credit percentage steps down after 2032: 26% for systems installed in 2033, 22% for 2034 installations, and zero for systems placed in service after December 31, 2034. But no income phase-outs or household caps apply through 2032, making the current window the most favorable for middle-income and high-income households alike.
The federal Residential Clean Energy Credit (Section 25D) ended for expenditures made after December 31, 2025, and the IRS treats an expenditure as made when installation is completed (IRS FS-2025-05).
How Much Can You Claim? Understanding the Annual and Equipment Caps
Geothermal heat pump installations carry no federal maximum cap—homeowners who spend $15,000 claim $4,500, those who invest $40,000 claim $12,000. The federal Energy Efficient Home Improvement Credit (Section 25C) ended for property placed in service after December 31, 2025 (IRS FS-2025-05).
And the credit applies per residential property, not per taxpayer. So a San Diego homeowner who installs geothermal systems at both a primary residence and a qualified second home claims 30% of costs for each property in the same tax year. The federal Residential Clean Energy Credit (Section 25D) ended for expenditures made after December 31, 2025, and the IRS treats an expenditure as made when installation is completed (IRS FS-2025-05).
| System Component | Qualifying Costs | Credit Calculation |
|---|---|---|
| Ground loop installation | $12,000–$18,000 | 30% of actual cost |
| Heat pump equipment | $8,000–$12,000 | 30% of actual cost |
| Labor and permitting | $3,000–$5,000 | 30% of actual cost |
What Geothermal Equipment Qualifies for the San Diego Tax Credit?
Only ground-source heat pump (this federal credit ended for expenditures made after December 31, 2025) systems that meet ENERGY STAR Most Efficient criteria qualify for the federal credit. These systems must achieve a minimum Coefficient of Performance (COP) of 3.5 for closed-loop installations and 4.0 for open-loop systems, plus an Energy Efficiency Ratio (EER) of at least 17.1 for closed-loop and 21.1 for open-loop configurations.
So water-source heat pumps connected to municipal water systems don't qualify, nor do air-source heat pumps despite their "geothermal" branding by some manufacturers. And hybrid systems that combine geothermal with natural gas backup forfeit the credit entirely—the IRS requires 100% renewable energy operation.
Equipment costs include the heat exchanger, ground loop piping, drilling or excavation, circulation pumps, distribution system components, and electrical upgrades necessary for operation. But cosmetic landscaping restoration after loop installation doesn't qualify, nor do separate cooling towers or supplemental water heaters.
"Geothermal heat pumps use the constant temperature of the earth as the exchange medium instead of the outside air temperature." — Department of Energy Geothermal Heat Pumps
Do You Qualify? Income Limits and Eligibility Requirements
The federal geothermal tax credit imposes zero income restrictions through December 31, 2032. San Diego households earning $50,000 or $500,000 claim the same 30% credit, unlike state rebate programs that cap eligibility at 80% of Area Median Income ($111,200 for a four-person household in San Diego County).
But taxpayers must have sufficient tax liability to absorb the credit. A $7,500 geothermal credit requires at least $7,500 in federal income tax owed for the installation year. And excess credits carry forward indefinitely—homeowners who owe $4,000 in taxes claim $4,000 in year one and the remaining $3,500 when filing the following year's return.
Primary residences, second homes, and new construction dwellings qualify. Rental properties, vacation homes not used personally, and commercial buildings don't. And homeowners who sell their property before filing can't transfer the credit to the new owner—only the taxpayer who paid for the installation and uses the residence claims the benefit.
What Form Do You File to Claim the Geothermal Tax Credit?
Form 5695 only covers qualifying work completed by December 31, 2025 and claimed on a 2025 return; the federal 25C and 25D credits ended after that date (IRS FS-2025-05). Line 1 of Part I captures geothermal heat pump property costs, which flow to Line 14 of Schedule 3 and reduce total tax owed on Form 1040, Line 21.
So homeowners retain invoices showing equipment model numbers, ENERGY STAR certification, installation dates, and total costs including labor. The IRS doesn't require submitting these documents with the return, but auditors request them when reviewing claimed credits years after filing.
And manufacturers' certifications that confirm equipment meets federal efficiency standards prevent disallowance. San Diego County building permits don't prove tax credit eligibility—only ENERGY STAR Most Efficient certification and documented costs establish qualifying expenditures.
Use our free rebate calculator to estimate your combined federal, state, and utility savings before committing to a geothermal installation.
When Does the Tax Credit Start and End? Important Deadline Information
The federal Residential Clean Energy Credit (Section 25D) ended for expenditures made after December 31, 2025, and the IRS treats an expenditure as made when installation is completed (IRS FS-2025-05). "Placed in service" means the installation is complete and operational—homeowners who sign contracts in 2032 but don't finish construction until 2033 claim only 26% unless they can prove the system operated before December 31, 2032.
And partial-year installations don't prorate. A system completed on December 15, 2026 claims the full 30% credit when filing the 2026 return in April 2027. But systems started in 2026 and completed in 2027 claim based on the 2027 percentage unless the taxpayer can demonstrate partial functionality in the earlier year.
The credit expires entirely for systems placed in service after December 31, 2034. So San Diego homeowners planning geothermal installations in the 2030s face declining incentives: 30% through 2032, 26% in 2033, 22% in 2034, and zero afterward unless Congress extends the program.
Can You Stack the Geothermal Credit With Other Incentives? State and Federal Rules
Federal tax credits stack with California state rebates, utility incentives, and local municipal programs—the IRS doesn't reduce the 30% credit when homeowners receive additional funding. So a San Diego resident who claims a $7,500 federal credit plus a $3,000 San Diego Gas & Electric rebate saves $10,500 total on a $25,000 installation.
But utility rebates that exceed equipment costs do reduce the federal credit base. A homeowner who receives a $15,000 rebate on a $15,000 system can't claim a federal credit because net out-of-pocket costs equal zero. And tax-exempt entities like nonprofits and government agencies don't qualify for tax credits, though they access separate grant programs.
California's Property Assessed Clean Energy (PACE) financing doesn't count as a rebate—homeowners who finance geothermal installations through PACE loans still claim 30% of total system costs. And mortgage interest deductions apply separately, creating triple savings: federal tax credit, mortgage interest deduction, and reduced energy bills.
| Incentive Program | 2026 Amount | Stacking Allowed? |
|---|---|---|
| Federal tax credit (IRA) | Ended Dec 31, 2025 | Ended Dec 31, 2025 |
| SDG&E Energy Efficiency Rebate | Up to $3,000 | Yes |
| TECH Clean California Heat Pump | $3,000–$7,000 | Yes |
How Do You Apply for the Geothermal Tax Credit in San Diego?
Form 5695 only covers qualifying work completed by December 31, 2025 and claimed on a 2025 return; the federal 25C and 25D credits ended after that date (IRS FS-2025-05). Contractors don't submit paperwork on behalf of homeowners, and the IRS doesn't maintain a geothermal credit registry or approval database.
Form 5695 only covers qualifying work completed by December 31, 2025 and claimed on a 2025 return; the federal 25C and 25D credits ended after that date (IRS FS-2025-05). And taxpayers who use professional preparation services provide installers' invoices and manufacturers' certifications to their accountant or tax software.
Form 5695 only covers qualifying work completed by December 31, 2025 and claimed on a 2025 return; the federal 25C and 25D credits ended after that date (IRS FS-2025-05). But manual filers download the form from IRS.gov, complete Part I (Residential Energy Efficient Property Credit), and transfer the Line 14 total to Schedule 3, Line 5.
The IRS processes geothermal credits within standard refund timelines—homeowners who file electronically in early February receive refunds including the credit by late February or early March. Form 5695 only covers qualifying work completed by December 31, 2025 and claimed on a 2025 return; the federal 25C and 25D credits ended after that date (IRS FS-2025-05).
Official Sources
- IRS Energy Efficient Home Improvement Credit — Federal tax credit forms, instructions, and eligibility requirements (note: the federal 25C and 25D credits ended for projects completed after December 31, 2025)
- Department of Energy Geothermal Heat Pumps — Technical specifications and efficiency standards for qualifying systems
- ENERGY STAR Most Efficient Requirements — Certification criteria and product databases for eligible equipment
Frequently Asked Questions
What are the eligibility requirements for geothermal tax credits in San Diego?
San Diego homeowners must install ENERGY STAR Most Efficient ground-source heat pumps at a primary or second residence to qualify. Systems must meet minimum COP of 3.5 (closed-loop) or 4.0 (open-loop) and EER of 17.1 or 21.1 respectively. And installations must occur between January 1, 2022 and December 31, 2032, with no income limits or household caps through that period.
How much can you save with a geothermal tax credit in California?
California homeowners save 30% of total installation costs through the federal credit, plus $3,000–$7,000 from state and utility rebates. A $25,000 geothermal (this federal credit ended for expenditures made after December 31, 2025) system generates a $7,500 federal credit, potentially combined with SDG&E rebates of $3,000 and TECH Clean California incentives up to $7,000, reducing net costs to $10,500–$14,500.
Do geothermal systems qualify for federal tax credits in 2026?
The federal Residential Clean Energy Credit (Section 25D) ended for expenditures made after December 31, 2025, and the IRS treats an expenditure as made when installation is completed (IRS FS-2025-05). The Residential Clean Energy Credit under the Inflation Reduction Act remains at 30% through December 31, 2032, then reduces to 26% in 2033 and 22% in 2034 before expiring.
What is the application process for claiming a geothermal tax credit?
Form 5695 only covers qualifying work completed by December 31, 2025 and claimed on a 2025 return; the federal 25C and 25D credits ended after that date (IRS FS-2025-05). Retain invoices showing equipment model numbers, ENERGY STAR certification, installation dates, and total costs. The credit flows to Schedule 3, Line 5, and reduces total tax owed on Form 1040, Line 21.
How does a geothermal tax credit compare to other renewable energy incentives?
The federal home energy tax credits (Sections 25C and 25D) ended for projects completed after December 31, 2025 (IRS FS-2025-05). And geothermal installations access both the uncapped Residential Clean Energy Credit and state rebates simultaneously, unlike efficiency improvements under the $1,200 combined cap for windows, doors, and insulation.
Ready to calculate your exact savings? Use our rebate calculator to combine federal tax credits with San Diego County utility rebates and state incentives—get your personalized estimate in under 60 seconds based on your home size, current heating system, and household income.
Updated: April 14, 2026 — fact-checked by DuloCore Research. About our editorial process.
Check your California heat pump rebate eligibility — see the programs you qualify for and the dollar amounts on our California heat pump rebate finder.