Almost nobody in this trade will put a geothermal number in front of you without a sales visit first. I am going to, because the most common question people ask about geothermal is what it costs, and dodging it wastes your time and mine. If you would rather see the number as a monthly payment than as a project total, that is what geothermal costs per month in Oklahoma.

The unit replacement numbers below are not brochure numbers. They come off my own completed job records, January 2018 through September 25, 2026. The rebuild starting price, the loop price per foot and the service call prices are my current published prices.

The three ways this goes

If your loop is good and the unit is tired

Rebuild, from $3,500

A rebuild reuses the expensive part you already paid for, the loop in the ground, and puts the system back in service. It buys eight to ten years against a full replacement. When the loop verifies good, geothermal rebuilds carry up to a five year warranty. I also pulled ten years of Oklahoma electricity rate history from the federal filings, so you can see what power has actually done around here.

The common one, the unit only. Your loop stays

Unit replacement, most run $20,000 to $25,000

This is the geothermal install I do most often, and it is the unit only. New geothermal equipment tied into the loop already in your yard. The loop stays where it is. In 700+ completed geothermal jobs in my records since 2017, I have not replaced a single ground loop field. I have loops in the ground out there that are on their third generation of equipment. Same pipe, third unit. That range comes from 36 completed unit replacements in my own records. The median on the 18 since 2023 is $22,252, and 17 of those 18 landed between $20,000 and $25,000. Some come in under and some run over, depending on tonnage, ductwork and what the electrical needs.

No loop in the ground yet

New system, the loop is $17 a foot

A brand new geothermal system means putting a loop in the ground, and that is what makes the number bigger. The loop runs $17 a foot, and how many feet you need depends on the size of the system, your soil, and whether we trench a horizontal field or drill vertical bores. I size that to your house rather than off a chart, so the total goes on a written estimate. The Free Geothermal Consultation costs nothing (weekends statewide as availability allows; on a weekday I start with a phone pre-qualification and ask for your utility bills first, then we set the visit). If you already have a well, the loop field may come off the estimate altogether: farm and ranch geothermal.

Where these numbers come from

The replacement range is measured from completed jobs in my own system, not from a price book and not from a national average: 36 geothermal unit replacements on existing loops, completed January 2018 through September 25, 2026, 18 of them since 2023. Each figure is the invoiced total for the whole job: the geothermal unit, labor and install materials, plus anything else on that same invoice, like a thermostat, heat strips, a flow center, or duct and electrical work, after any discount on the invoice. It does not include a new loop, because the loop was already in the ground, and it is before any utility rebate or financing cost. I am showing you the middle of my own book.

One thing that range tells you honestly: geothermal pricing moved. My median replacement was around $16,000 in 2021 and about $22,700 in 2026 so far. Equipment costs went up for everybody. It has been roughly flat the last three years.

What is not in the price

Utility and co-op rebates change by provider and by program date. Tell me your ZIP and your electric utility and I will check the current official program before anybody quotes you a number. I will not guess on a rebate.

If the number is the problem

Two honest options. A lease puts a complete system in with nothing down and the loop inside one monthly payment, and I stay your service company for ten years. Or financing, through Synchrony, Wells Fargo, Wisetack, Klarna or JB Financing. Financing covers repairs and maintenance plans too, not just new systems.

What a service call costs

Separate from installs. A geothermal diagnostic is $348 flat, weekday or after hours, same number either way. That is a full performance audit, loop pressure, refrigerant charge, desuperheater, controls and heat exchanger, with a written report and a quote before I leave. A geothermal tune up is also $348.

Common questions

How much does a geothermal system cost in Oklahoma?

A replacement on an existing loop most often runs $20,000 to $25,000, measured across 36 of my own completed unit replacements from January 2018 through September 2026, with a 2023 and later median of $22,252. A new system also needs a loop, which is $17 a foot sized to your house. A rebuild of an existing system starts around $3,500.

How much does a geothermal ground loop cost?

$17 a foot. How many feet depends on system size, soil and whether we trench horizontally or drill vertical bores, so I size it to your house and put the total in writing.

Is it cheaper to replace just the geothermal unit?

Usually yes, by a wide margin, because the loop is the expensive part and a sound loop can be reused. In 700+ completed geothermal jobs in my records since 2017, I have not replaced a single loop field, and I have loops still working on their third generation of equipment.

What incentives can lower the cost of geothermal in Oklahoma?

Utility rebates are the big one, and they vary by provider. Tell me your ZIP code and electric utility and I will check your current program before I quote any amount. If you would rather not pay for the system up front, my Full Coverage Geothermal Plan is a 10-year lease with $0 upfront: the system, loop, install, maintenance and repairs ride in one monthly payment, subject to the terms of the contract, and you have the option to buy it out at the end.

Why is geothermal more expensive than a regular system?

The loop. Everything else is comparable, but a geothermal system needs pipe in the ground before you own any equipment. That is also why a replacement on an existing loop is so much cheaper than a first install.

Do you charge for a geothermal estimate?

No. The Free Geothermal Consultation costs nothing. A diagnostic on a system that is already broken is $348 flat and comes with a written report.

Want a real number for your house?

The Free Geothermal Consultation costs nothing. Tell me your town, your system size and whether you already have a loop.

Call 405-375-4822 or book a free geothermal consultation.

Free Geothermal Consultation: weekends statewide as availability allows. On a weekday I start with a phone pre-qualification and ask for your utility bills first, then we set the visit. It is not the paid $348 diagnostic: diagnostic testing of an existing geothermal system, including one that has stopped working, is the paid $348 diagnostic.