For a business, commercial geothermal HVAC comes down to three things: a federal tax credit worth 30% to 50% of the system, lower energy and maintenance costs for decades, and far fewer equipment replacements. If you're replacing aging rooftop units or building new in the St. Louis area, it's worth pricing both ways before you sign a conventional bid.
The tax credit
Geothermal heat pump systems on commercial buildings qualify for the federal investment tax credit under Section 48. The credit is a percentage of the geothermal system's cost:
- 30% base credit for projects that start construction by the end of 2032 (26% in 2033, 22% in 2034, then none).
- +10% when the steel, iron and manufactured parts are U.S.-made (the domestic content bonus).
- +10% when the site is in an energy community: near a retired coal mine or coal plant, in a qualifying fossil-fuel area, or on a brownfield. Here's how to check.
The homeowner geothermal credit ended after 2025, but the commercial credit continues on the schedule above. Systems under 1 megawatt get the full base credit without the prevailing wage and apprenticeship rules. Larger systems need them, and our Local 562 union pipefitters meet those rules.
How a business uses the credit
A business takes the credit against its federal income tax for the year the system is placed in service. If the credit is larger than what you owe, the tax code lets you sell it to another taxpayer for cash, a process called credit transfer. Your CPA can tell you which route fits, and how the credit interacts with depreciation on the system.
Here's what it looks like on a building with a $500,000 conventional HVAC bid, using our planning estimate that geothermal runs about 44% more:
| Conventional HVAC | $500,000 |
| Geothermal system | $720,000 |
| 40% tax credit | −$288,000 |
| Geothermal after the credit | $432,000 |
After the credit, geothermal comes in $68,000 under the conventional bid, and it keeps saving every year after that. Try it with your own number in the geothermal calculator.
Lower operating costs
A few hundred feet down, the ground here stays in the mid-50s °F all year. The heat pumps trade heat with that steady water instead of with 10°F or 98°F outdoor air, so they use less energy. In Oak Ridge National Laboratory's studies, geothermal buildings used about 26% less energy than conventional ones. No gas is burned for heat, so a cold winter with high gas prices doesn't land on your bottom line.
Fewer replacements
Rooftop units last about 15 years. Indoor geothermal heat pumps last 20 to 25, and the underground loop lasts about 50. For a business that owns its building, that means fewer major equipment replacements over the life of the building.
Other reasons businesses choose geothermal
- Less on the roof. No condensers or rooftop units means fewer roof penetrations, less weight and nothing up there to steal or storm-damage.
- Quiet. The heat pumps sit indoors. Customers, tenants and neighbors don't hear outdoor fans.
- The ground stays usable. The well field goes under a parking lot, lawn or landscaped area, and the surface is restored on top.
- Simple maintenance. The loop is sealed and needs essentially nothing. Heat pumps need filters and routine checkups.
Which buildings are the best fit
- Buildings whose rooftop units or boilers are near the end of their life
- New construction and additions, where the well field goes in before anything is built on top
- Sites rebuilding a parking lot, so the drilling and paving happen once
- Buildings with long operating hours, like offices, medical offices, hotels, senior living and multifamily, where energy savings add up fastest
- Owners who plan to keep the building long term
Churches and other nonprofits qualify too, and they get the credit as a cash payment instead of a tax credit. Here's how that works.
Next step
A feasibility review looks at your building's heating and cooling load, the ground you have, the conventional price, and the credit percentage your site qualifies for. Get an estimate or call 636-327-4238.