The quote looked solid on paper.
A driller, a heat pump unit, the ground loops, the labor. Then, at the bottom of the estimate, the line that made the whole project pencil out: a 30 percent federal credit. For hundreds of thousands of homeowners, that single line rewrote the math. Now it is gone, removed on a fixed date with no phasedown.
How did a credit that broad disappear so cleanly, and what does the math look like without it?
How the law’s mechanism made the cutoff instant and absolute
The mechanism is legislative, not geological. The One Big Beautiful Bill Act (OBBBA), signed into law on July 4, 2025, introduces sweeping changes to the US energy tax credit and incentives landscape. Enacted as Public Law 119-21, it is a sweeping federal statute passed by the 119th United States Congress containing tax and spending policies. Buried within it are provisions that accelerated the termination of a range of clean energy tax credits, including Section 25D. P.L. 119-21 repealed the residential clean energy credit (RCEC) for expenditures made after calendar year 2025. The residential geothermal credit had been running at a flat 30 percent with no dollar cap, and the law ended it without a phasedown or a grace period. Section 25C, the residential energy-efficient home improvement credit, and Section 25D, the residential clean energy credit, were both repealed and set to expire December 31, 2025.
Per the statute, 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 prevents the taxpayer from claiming the Section 25D credit. A contract executed in November 2025 with system commissioning in February 2026 does not qualify. The date of completion is the only date that counts.
So the mechanism is simple and brutal. A buyer who finished in 2025 saved up to five figures. A buyer whose crew hit a drilling delay in January lost every dollar of that federal floor.
What a typical geothermal install actually costs, and what the credit was covering
On average, a geothermal heat pump installation costs $15,000 to $40,000 or more. Challenging terrain or complex vertical-bore jobs can push well past that. A horizontal loop system is generally more affordable ($12,000, $30,000) but requires land, while vertical loops are more expensive due to drilling depth and fit smaller lots ($20,000, $45,000). Those numbers dwarf the cost of a conventional gas furnace and central air setup, which typically runs $8,000 to $15,000. The gap is real, and the 30 percent credit existed precisely to close it.
The net cost of installation rose by $4,500 to $12,000 on a typical system overnight, and payback periods lengthened accordingly. State rebates and utility incentives partially fill the gap, but there is no federal floor left for residential buyers.
Meanwhile, electricity rates keep climbing. Utilities in Colorado and Washington have both sought rate increases in recent months to cover grid spending, which is the central reason geothermal’s low operating cost was so attractive in the first place. Higher electricity bills make any system that uses less power more appealing, but only if the upfront cost is manageable.
The scale of the market that relied on this credit
Incomplete IRS figures show that at least 80,730 households took advantage of the credit for a geothermal system in 2023, with the average credit just over $12,000. On a $25,000 install, that 30 percent credit translated directly into a five-figure reduction in what you owed the IRS.
Homeowners had not been allowed to claim the 30% credit for geothermal heat pumps installed after 2025. The credit had been available on such items placed in service through 2034, but at a 26% rate in 2033 and 22% rate in 2034. Buyers who signed contracts in 2023 or 2024 were operating under a reasonable assumption that the credit would still exist when their system went live.
That assumption proved wrong for anyone who finished after the cutoff. Trade publications covering the heating and cooling industry have noted that residential shipments may fall sharply in the near term as a direct result of the credit’s removal.
Where the payback math now stands, and what partial paths remain
Without the federal credit, a buyer in a state with no dedicated geothermal incentive faces the full sticker: $15,000 to $40,000 or more installed, with complex jobs reaching higher. Compare that to $8,000 to $15,000 for a high-efficiency gas furnace plus central AC, or $10,000 to $20,000 for a modern air-source heat pump. The competitive disadvantage is now significantly wider than it was before the cutoff.
Some state-level relief does exist. New York offers a credit equal to 25% of qualified geothermal energy system expenditures, capped at $5,000 for systems placed in service on or before June 30, 2025, and $10,000 for systems placed in service on or after July 1, 2025. New York’s NYS Clean Heat utility rebates for geothermal run $14,000 to $40,000 depending on the utility. Massachusetts offers a rebate up to $13,500 and zero-percent financing through its Mass Save program. But most of the country has nothing close to that, and many states have no program at all.
