Geothermal Myths, Corrected: What Oklahoma Homeowners Get Wrong

I am Dave Hartzell, 47 years in HVAC and 15+ years running Hartzell’s Heat & Air out of Kingfisher, IGSHPA accredited. Most of what people get wrong about geothermal is not a lie somebody told them. It is two technologies sharing one name, sales talk that got ahead of itself, and a tax rule that changed.

Myth: geothermal means volcanoes, steam vents, and drilling toward magma

A geothermal heat pump and a geothermal power plant are two entirely different machines that share one word and nothing else. A power plant taps deep volcanic heat to generate electricity. A geothermal heat pump generates no electricity and never touches volcanic heat: it moves heat between your house and ground a few feet down, which in Oklahoma sits near room temperature all year.

Search the single word geothermal and you get Iceland, geysers and steam turbines, none of which touches the box that heats a house in Kingfisher County. Dig 6 feet down here and the dirt is right around 60 degrees in January and 60 again in July. In winter the heat pump pulls heat out of that ground instead of 20 degree air, and in summer it drops heat back into it.

It is also why cold does not stop it: an air source heat pump loses capacity exactly when the air gets coldest, and my loop does not know there is a wind chill. Mechanics: how a geothermal heat pump works.

Myth: there is a 30% federal tax credit on a home geothermal system

Not any more, and this is now the most expensive myth on the page. The residential Section 25D credit, the 30% number people still repeat, expired December 31, 2025 per IRS Fact Sheet FS-2025-05, so I will not promise you a federal credit on a house in 2026. Check current IRS and ENERGY STAR guidance with your own tax professional, and leave carryforward to your preparer.

What is real is utility money. CKenergy Electric Cooperative pays $2,000 per ton on a new geothermal install, up to $24,000. Three qualifiers: members only, new installs only because the replacement rebate was discontinued, and CKenergy covers Blaine, Canadian and counties west and south but not Kingfisher County, so a Kingfisher address is not on this program. Details: the CKenergy geothermal rebate.

Other co-ops vary, and OG&E residential rebates are closed for 2026. I am not printing figures for the rest, because a stale number on a page is how people get disappointed. Call me with your address and utility. Commercial buildings run on a different code section, and that credit is still alive: commercial geothermal in Oklahoma.

Myth: geothermal is magical free energy, and it beats a furnace on price

Nothing is free, and geothermal is a premium purchase that costs more up front than a furnace and an air conditioner. What it does is cost less to run, roughly 50% less HVAC energy use, every month for decades. People are right to push back when a salesperson blurs those two things.

A furnace burns fuel to make heat and gives back slightly less than you fed it. A geothermal heat pump moves heat instead of making it: at a COP of 4.5 that is about $4.50 of heat for every $1 of electricity. Note the wording, roughly 50% of HVAC energy use, not half your electric bill. Check my math in what COP means.

Myth: geothermal heat pumps cannot heat domestic hot water

They can, and the ones I install do. A desuperheater is a small heat exchanger built into the geothermal unit that takes waste heat off the compressor and sends it to your water heater tank instead of down the loop.

The honest limit: a desuperheater does not replace your water heater, it preheats. It makes the most in summer, when heat pulled out of your house lands in your shower instead of the ground, and the least in deep winter. The tank stays. See what a desuperheater is and geothermal water heating in Oklahoma.

Myth: a geothermal system has nothing to do with humidity levels

That is wrong, and in Oklahoma it is wrong in the way that ruins a July. Any cooling system removes moisture while it runs, and a correctly sized geothermal system running longer, gentler cycles pulls more water out of the air than an oversized unit that blasts for eight minutes and quits.

Humidity is the real comfort problem here, not the thermostat. A house at 74 degrees and 65% relative humidity feels miserable; at 76 and 45% it feels fine and costs less to hold. Two stage and variable speed geothermal equipment adds a dehumidification mode that slows the blower on purpose. Oversizing is the failure mode, and a load calculation settles it before anything is ordered.

Myth: geothermal has to go about thirty feet deep

There is no one depth, because it depends entirely on which loop goes in. A horizontal loop goes into trenches typically 4 to 6 feet down. A vertical loop goes into bores that commonly run a couple hundred feet. A pond loop is neither, it lies in the water.

Thirty feet is close to the one answer that is never right: too deep to trench economically, too shallow to be a bore. Loop type is also where the you-need-acres worry comes from. A horizontal loop wants yard; a vertical loop needs almost no surface, which is how geothermal fits a normal lot in Enid or Edmond. All three: horizontal vs vertical vs pond loop.

Myth: it will tear up my yard and it will never look right again

The yard gets disturbed, and then it grows back. Trenching leaves scars for a season, a vertical bore field barely marks the surface, and by the next spring most of my customers cannot point to where the loop went in.

It is not a tidy week. There is a rig, spoil piles, and ruts if the ground is soft. What I control is where the equipment sits and how the backfill is compacted, because loose backfill settles into a sunken stripe across a lawn two years later. That is workmanship, not geothermal. Stage by stage: will geothermal tear up my yard.

Myth: geothermal maintenance is exotic and nobody around here can work on it

Routine geothermal maintenance is less work than a furnace plus an air conditioner, not more. The hard part was never the maintenance, it is finding somebody with the tools and the accreditation to diagnose a loop. I hear that constantly: owners with a perfectly good system call around and get told nobody has the gauges to check loop pressure.

The service list is short: filters, coil, condensate, loop pressure, flow, antifreeze. No outdoor condenser baking in the sun and nothing out there to hail. I am IGSHPA accredited, a ClimateMaster GeoElite dealer, and I own the loop tools. A geothermal diagnostic is $348 flat, weekday or midnight, a new system estimate is free, and geothermal service runs statewide across Oklahoma, wider than my seven daily service counties.

Questions I get after somebody reads all that

Is a geothermal heat pump the same thing as a geothermal power plant?

No. They share a name and nothing else. A power plant uses deep volcanic heat to generate electricity. A residential geothermal heat pump generates no electricity and uses no volcanic heat, it moves heat between your house and ground sitting near 60 degrees year round.

Is there still a 30% federal tax credit for home geothermal in Oklahoma in 2026, or did it expire?

It expired. The residential Section 25D credit ended December 31, 2025 per IRS Fact Sheet FS-2025-05, so nobody should quote you 30% on a house today. Check current IRS and ENERGY STAR guidance with your tax professional, then ask about utility rebates: CKenergy members get $2,000 per ton, up to $24,000. Commercial geothermal sits under a different code section and still carries a credit.

Does a geothermal system dehumidify a house in Oklahoma?

Yes, and it is one of the better reasons to own one here. Every cooling system pulls moisture while it runs, and a properly sized geothermal system runs longer, gentler cycles that remove more water per hour than an oversized unit short cycling.

How much does a geothermal diagnostic cost in Kingfisher Oklahoma?

A geothermal diagnostic is $348 flat, the same $348 on a weekday afternoon or at midnight. It covers loop pressure, refrigerant charge, desuperheater, controls and heat exchanger, with a written report before I leave.