Does Geothermal Actually Appraise in Oklahoma?

I am Dave Hartzell, 47 years in HVAC, 15+ years running Hartzell’s Heat & Air in Kingfisher. Geothermal is what I am known for, so sellers ask me this monthly: if I put geothermal in this house, does the appraisal give it back, or do I eat it at closing?

Sometimes it appraises and sometimes it does not, and it turns on the paperwork you hand the appraiser more than on what you spent. I am not printing a dollar figure here.

Why your invoice does not turn into value on its own

If your buyer is getting a conventional loan, Fannie Mae’s guidance is what your appraiser works from. Section B4-1.3-05 of the Selling Guide tells the appraiser to note energy efficient items in the Additional Features field, then bars valuing them “on a mechanical dollar-for-dollar basis based on equipment and installation cost, or the discounted present value of expected cost savings.”

That kills both arguments a homeowner reaches for. You cannot say the equipment cost this much, so add that. You cannot say it saves this much a year, so capitalize it. The appraiser needs evidence of how buyers actually reacted. Value follows what a buyer will pay, not your check.

What no comparable sales really means where you live

Now put that rule in a Kingfisher neighborhood where your house is the only one with a ground loop. The appraiser looks for evidence of buyer reaction and finds none, because there are no geothermal sales.

On AppraisersForum.com, one appraiser wrote about a geothermal home: “I could not find any comparables with similar heating. Therefore, I could not make an adjustment because I do not know what the market reaction is yet.” Another was blunter: the typical buyer will not pay anywhere near what a geothermal system costs to install. That is professional testimony, not a study. In a thin market an appraiser may adjust a little or not at all. That is the rulebook, not stubbornness.

Name the form: the Appraisal Institute Green and Energy Efficient Addendum

Most homeowners have never heard of the document built for this exact problem: the Appraisal Institute’s Residential Green and Energy Efficient Addendum, currently AI Reports Form 820.07, copyright 2025.

• It is the appraiser’s form, not yours. The certification reads “The appraiser hereby certifies.” Builders, contractors and homeowners are encouraged to fill it in and hand it to appraisers, agents and lenders.
• Timing is where people blow it. It is meant to reach the appraiser before the appraisal is completed.
• It has a geothermal checkbox and no geothermal number. Under HVAC and Related Equipment sits a Geothermal Yes or No box next to COP, EER, SEER and HSPF fields. Every dollar field is blank, filled in from your documentation.

Its own notice says the addendum “is not made as a representation or as a warranty as to the efficiency, quality, function, operability, reliability or cost savings of the reported items.” It documents your system. It does not price it.

Exactly what to hand an appraiser

1. The addendum, filled in, delivered before the inspection.
2. Make, model and serial of the heat pump, plus the rated COP and EER for that model. The form has fields for those, and guessing is worse than a blank. See what COP means and what a ton is.
3. Twelve to twenty four months of utility bills. Your strongest exhibit, because buyers react to operating cost. What geothermal does to your electric bill covers how to read them.
4. The itemized install invoice and date. Not to claim its dollar value, but to prove age, tonnage and scope.
5. Loop documentation. Closed or open, horizontal, vertical or pond, plus depth, tonnage and who drilled it. Oklahoma helps here: the Water Resources Board licenses drillers for heat exchange wells, and OAC 785:35-7-1.1 sets standards for the borehole, casing, loop pipe and grouting. Your loop is regulated work with a paper trail.
6. Maintenance records. Service tickets tell the appraiser and the buyer’s inspector the system was cared for.
7. Warranty paperwork. Hand over all of it and let the buyer’s people read the transfer terms. I will not tell you a warranty automatically follows the house. Get the terms in writing from the manufacturer before anyone counts on it.

The numbers I refuse to print

Search this and you will find contractor pages promising a specific five figure bump in value. I chased the claim down and could not find a primary or peer reviewed source that states it for geothermal at all. The likely ancestor is a Nature Energy study of 400,000 United States property sales, except it measured air source heat pumps, a different machine.

One peer reviewed study is about ground source. Jussi Vimpari at Aalto University published it in Energy Efficiency in 2023, covering 19,008 detached house sales across eight Finnish cities. Those houses sold at a statistically significant premium of about 5.3 percent. Real evidence a premium can exist, and also Finland, with different prices, climate and heating baseline. He does not convert it to an American figure and neither will I.

The oldest honest finding here, from The Appraisal Journal in 1998, is that home value tracks reduced fuel bills, not equipment cost. Geothermal is never mentioned in it. Your utility bills, not your invoice, are what move an appraisal.

What I recommend, and what it costs

If you are installing, treat appraisal credit as upside and buy geothermal for the comfort and operating cost. Selling? Build the packet above and get it to the lender early. Buying a house that already has geothermal? Have it checked before you close.

A new system estimate is free. A geothermal diagnostic is $348 flat. Replacement work is quoted separately before approval. A standard residential service call is $210 flat, a $99 dispatch fee plus a $111 diagnostic fee. There is always a dispatch fee and always a diagnostic fee.

Maintenance records matter at resale, and plans start at One Visit Spring or Fall 360 for $199, up through Full Year 360 at $499. A new system can be financed through Synchrony, Wells Fargo, Wisetack, Klarna or JB Financing.

One tax note. The federal residential clean energy credit under Section 25D has expired and does not apply to property placed in service after December 31, 2025, so do not let anyone price a house around it. Kingfisher, Okeene and Watonga are municipal utility towns, and OMPA pays up to $800 per cooling ton there: a cap, not a guarantee, requiring a desuperheater. Alfalfa Electric Cooperative pays $1,050 per ton for ground source against $150 for air source in Garfield and Major counties. Send tax questions to your tax professional.

Where I work

Geothermal is statewide for me. I go anywhere in Oklahoma for a geothermal customer: Kingfisher, Okarche, Hennessey, Watonga, Piedmont, Edmond, Yukon, El Reno, Guthrie, Enid, Okeene, Oklahoma City, Lawton, Broken Bow and Durant. One shop, here in Kingfisher, and I bring in a driller I trust when a job needs a rig. Daily service calls stay inside Kingfisher, Canadian, Oklahoma, Garfield, Major, Logan and Blaine counties. Geothermal does not. I am IGSHPA accredited. 4.8 stars, 300+ Google reviews.

Questions people ask me about geothermal and appraisals

Does geothermal add value to my house in Oklahoma?

It can, and nobody can promise a number. Fannie Mae bars valuing an energy feature from installation cost or expected savings, so the appraiser needs market evidence that most Oklahoma neighborhoods cannot supply.

What is the green addendum and who fills it out?

The Appraisal Institute Residential Green and Energy Efficient Addendum, currently AI Reports Form 820.07. The appraiser signs it, so it is their form. You or your contractor fill it in and deliver it early.

What if no other house in my neighborhood has geothermal?

Then your appraiser may struggle, and expect that going in. With no comparable sales there is nothing to extract an adjustment from. Utility bills and a completed addendum are your strongest cards.

Do I get the federal tax credit if I buy a house that already has geothermal?

No. The credit under Section 25D has expired, does not apply to property placed in service after December 31, 2025, and was for whoever installed the system. Ask a tax professional.

Does the geothermal warranty transfer when I sell the house?

Do not assume it does. I have not seen a manufacturer document that promises an automatic transfer. Pull the paperwork and get the terms in writing before closing.

How much does it cost to have a geothermal system checked before closing in Kingfisher Oklahoma?

A geothermal diagnostic is $348 flat. Replacement work is quoted separately before approval. It covers loop pressure, refrigerant charge, desuperheater, controls and heat exchanger, and you get a written report before I leave.

Want the system looked at, or a real number on a new one? Call 405-375-4822. Hartzell’s Heat & Air, 602 S Main St, Kingfisher OK 73750. Read is geothermal worth it in Oklahoma, book online, or see geothermal financing.