I was selected for inclusion in Marquis Who’s Who for 2026. After 45 years in this trade and 15+ years running my own shop in Kingfisher, that recognition lands different than I expected. It is not about a plaque. It is about a record of work, mostly out in the country, in homes and on gas plants and oil rigs, that someone took the time to verify.

I started in electrical at 10, was leading crews by 16, and have been heating and cooling buildings professionally since 1981. I have run service trucks, designed geothermal loops for 300-ton grow-houses, and spent seven years before HVAC as a Sprint network engineer on a $30 million FCC triangulation project. All of it informs how I show up to a service call today. 4.8 stars across 276 Google reviews tells me the work translates.

What this recognition means for customers

Practically, nothing changes. Dispatch is still $99. Diagnostic is still $111, credited toward the repair if you accept it. Tune-ups are $229. Estimates on new systems are free. I still answer the phone, and I am still the guy who shows up.

What the honor does, in my opinion, is confirm what people in central Oklahoma already know: there is a difference between an HVAC company that sells equipment and a Master HVAC technician who designs systems for the conditions they actually live in. Red dirt, hard water, 110-degree summers, and ice storms in February. I have worked through all of it.

About Marquis Who’s Who

Marquis Who’s Who has chronicled the lives of accomplished individuals and innovators across every significant field for over 125 years. Selection is based on documented professional achievement, leadership in a field, and contribution to community. More at marquiswhoswho.com.

Career highlights

• Owner and operator, Hartzell’s Heat & Air, Kingfisher Oklahoma, 15+ years
• 45 years in HVAC and electrical, started at age 10
• Recognized geothermal specialist in Oklahoma, grow-house installs from 200 to 300 tons
• Leading dealer for Trane and Mitsubishi in central Oklahoma
• Previously: Sprint network engineer, 7 years, $30M FCC 12-star triangulation project
• Previously: Entech Sales & Service LLC and TD Industries (top 100 firms US)
• Serves residential, gas plants, oil rigs, and commercial greenhouses

Credentials and memberships

• Master HVAC License (Oklahoma)
• NATE Certified
• IGSHPA Accredited Geothermal Installer
• Mitsubishi Diamond Dealer, Trane TCS SELECT, ClimateMaster GeoElite, Amana Brand Advantage
• BBB A+ Accredited, 11 years
• ASHRAE, ACCA, IGSHPA, Kingfisher Chamber of Commerce

Education

Oklahoma State University, AS in thermodynamics, 1989. O.T. Autry Vocational and Technical School, 1986. Woodward High School, 1981.

Original press release

The full press release, dated April 24, 2026, is published at 24-7PressRelease.com: View the release. You can also download the original press release as a PDF.

Frequently Asked Questions

What is Marquis Who’s Who and why does it matter for Hartzell’s customers?

Marquis Who’s Who has profiled leaders across U.S. industry for over 125 years. My 2026 inclusion is recognition of 45 years in HVAC and 15+ years running Hartzell’s Heat & Air in Kingfisher. For customers, it’s a third-party signal that the person installing your geo loop or sizing your Manual J has the depth to back it up.

Does Marquis Who’s Who recognition change Hartzell’s pricing or services?

No. Same Kingfisher shop, same crew, same $111 diagnostic and $229 tune-up. The honor is about my career, not a reason to charge more. Call 405-375-4822 for any service.

How long has Dave Hartzell been in HVAC?

45 years. I started at 18, worked 12 years at a competitor before opening Hartzell’s Heat & Air around 2011. That’s 15+ years as owner here in Kingfisher with 4.8 stars across 276 Google reviews.

Where can I read the Marquis Who’s Who press release?

It went out through 24-7PressRelease.com, release number 534217. There’s also a press page on this site listing it alongside the BBB A+ accreditation and Mitsubishi Diamond Dealer recognition.