Most HVAC techs spend their careers working on equipment that trades heat with outdoor air. A geothermal heat pump installer works on systems that trade heat with the ground instead. The refrigeration cycle inside the unit is familiar. What is new is everything outside it: loops buried in trenches or drilled hundreds of feet down, heat-fusion pipe joints, flushing and purging, and pump and fluid selection.
This guide covers what the job actually involves, the main installer credential, how pay fits into the wider HVAC picture, and an honest look at demand after the federal residential tax credit ended for systems placed in service after 2025.
How Geothermal Systems Work (the Installer's Version)
The U.S. Department of Energy's geothermal heat pump page explains the basic idea: a few feet down, the earth holds fairly steady between about 40°F and 70°F all year. That makes the ground warmer than winter air and cooler than summer air, so a ground-source heat pump has an easier job than an air-source unit in both seasons. Systems can heat, cool and, if equipped, make hot water.
Most systems are closed loops: water or a water-glycol mix circulates through buried or submerged plastic pipe, and a heat exchanger moves heat between that loop and the refrigerant. A less common design, direct exchange, runs refrigerant through buried copper tubing with no separate heat exchanger. DOE also describes open-loop and hybrid systems, the latter pairing ground loops with something like a cooling tower when cooling loads far exceed heating loads.
DOE says indoor components can last up to 24 years and the ground loop 50 years or more. For an installer, that means the loop is the part you only get one chance to do right.
Loop Types You Will Install
Loop choice depends on climate, soil, available land and local installation costs, according to DOE. Here is how the main closed-loop types compare on the details DOE gives.
| Loop type | How it is built (per DOE) | Typical use |
|---|---|---|
| Horizontal | Trenches at least 4 ft deep; pipes either stacked at about 6 ft and 4 ft, or side by side at about 5 ft in a 2-ft-wide trench | Usually the most cost-effective residential option, especially new construction with enough land |
| Vertical | Bores about 4 inches across, roughly 20 ft apart and 100 to 400 ft deep, with pipes joined by a U-bend at the bottom | Large commercial buildings and schools, or anywhere land is too tight for trenches |
| Pond or lake | Coiled pipe in a water body that meets minimum size, depth and quality standards; in cold climates at least 8 ft below the surface | Sites with a suitable pond nearby |
On many jobs, the drilling or excavation is subcontracted and the HVAC side handles the loop connections, flushing, the indoor unit and startup. On smaller residential jobs, one company may do all of it. Before taking a job, find out which part you would be doing; "geothermal installer" covers both.
What a Geothermal Heat Pump Installer Does Day to Day
The best map of the work is the content list for the main credential exam (covered below). It includes:
- Design and material options, and system layout
- Pipe joining
- Trenching and drilling
- Air and debris purging of the loop
- Pressure drop calculations
- Pump and fluid selection
- Thermal conductivity of the ground
- Start-up, performance checking and troubleshooting
Compare that with a standard residential service day. A lot is familiar: wiring, controls, refrigerant circuits, airflow, customer explanations. The new pieces are hydronic in nature. You need to be comfortable thinking about flow rates, head loss through the loop and how antifreeze concentration affects the system. If you have done any hydronic boiler work, you already have a head start.
The work environment is also different. Loop installation happens outside, often on a raw construction site with excavators or drill rigs nearby, in mud and weather. The indoor side is closer to a normal equipment install.
Why the loop matters so much: DOE notes that a qualified installer tests soil and ground makeup before choosing a design. A loop that is undersized or poorly purged will haunt the system for decades, and the fix means digging or drilling again. Contractors who do this work well tend to value careful, methodical techs over fast ones.
The IGSHPA Accredited Installer Credential
The International Ground Source Heat Pump Association (IGSHPA) Accredited Installer, often shortened to AI, is the credential most associated with geothermal installation. A 2024 HeatSpring guide to the IGSHPA AI lays out how it works:
- Prerequisite: you must complete an IGSHPA geothermal installer accreditation course first (the only exception is reinstating a prior AI).
- Exam: open book, 100 multiple-choice questions, 80% to pass, not proctored, taken on any device.
- Cost: the guide lists a $350 exam package that covers the exam, a three-year IGSHPA membership and a license to the relevant CSA standards, with two attempts included and a $150 fee for a third.
- Renewal: every three years, with 8 continuing-education points earned through work in geothermal or HVAC, memberships in approved groups such as IGSHPA, NGWA or ASHRAE, and training hours.
The guide says the credential is aimed at a wide group: installers, contractors, dealers, builders, drillers, engineers and utility reps who advise customers. Fees and rules can change, so confirm current details with IGSHPA or your course provider before you pay.
The AI sits on top of your normal HVAC credentials, not in place of them. You still need EPA Section 608 certification to handle refrigerant, plus whatever HVAC license your state or city requires. Local permits may also apply to the loop itself, so check with your local building department.
Pay, Demand and the 2026 Tax-Credit Change
BLS does not track geothermal installers as a separate occupation, and its HVAC mechanics and installers profile does not mention geothermal at all. The closest benchmark is that profile: a median of $61,010 a year ($29.33 an hour) in May 2025, with the top tenth earning more than $95,210, and 11% projected growth from 2025 to 2035. Plumbers, pipefitters and steamfitters, whose skills overlap with loop work, had a median of $63,800 in the same data. There is no verified figure showing a geothermal premium, so treat any you see in ads with caution and judge the specific offer.
Demand is where you need clear eyes. DOE says a geothermal system can cost several times as much as an air-source system of the same capacity, with energy savings paying back the difference in about 5 to 10 years depending on energy prices and incentives. For years, a big part of that incentive story was the federal residential clean energy credit, which covered 30% of qualified costs, geothermal heat pumps included. The IRS page for that credit now says it is not available for property placed in service after December 31, 2025.
What that means for your job search in 2026:
- Residential geothermal has lost one of its main selling points. Some homeowners will still buy for comfort, quiet and long life, and state or utility programs may help, but expect a harder sell than in 2023 to 2025.
- Commercial buildings and schools, which DOE identifies as the main users of vertical loops, are driven by different economics and longer planning cycles.
- Ask any geothermal employer what share of their work is residential vs. commercial and how their pipeline changed after the credit ended. A good company will have a straight answer.
How to Break Into Geothermal Work
- Get solid at regular HVAC first. Geothermal systems are heat pumps. If you cannot confidently diagnose an air-source heat pump, adding a ground loop will not help. Our how to become an HVAC technician guide covers the base path.
- Pick up hydronic basics. Pump curves, head loss and flow are daily tools in loop work.
- Find a contractor that already does geothermal. Search for dealers of geothermal equipment in your region, or ask your supply house which contractors buy loop pipe and fittings.
- Take the IGSHPA installer course and exam once you are working on these systems, so the material lines up with what you see in the field.
- Keep your air-source skills current. The DOE page notes dual-source units that combine air and ground sources. Being good at both makes you useful no matter which way the market moves.
The Bottom Line
Geothermal installation is a strong specialty for a careful, systems-minded HVAC tech, but it is a specialty, not a starting point. Learn heat pumps and basic hydronics first, then add the IGSHPA Accredited Installer credential once you are working for a contractor that does real loop work. With the federal residential credit gone for systems placed in service after 2025, lean toward employers with commercial, school or new-construction work rather than ones that depended mainly on residential retrofits.