15+ years • 6,500+ jobs completed • 1,500+ Oklahoma homes served
Straightforward pricing
- $99 dispatch on every truck roll. Free on new-install estimates.
- $210 flat residential service call: $99 dispatch plus $111 diagnostic. The diagnostic does not reduce the repair price.
- Written repair estimate: I give you a written repair estimate before repair work starts.
- Free estimates on new installs. No charge to walk through replacement options.
Call (405) 375-4822. 4.8 stars, 300+ Google reviews.
Controlled Environment & Specialty HVAC Systems
I’m Dave Hartzell, and my crew installs precision HVAC for controlled environments across central Oklahoma: server rooms, cannabis grows, lab spaces, and specialty facilities that need tight temperature and humidity control. Call 405-375-4822 for a consultation.
Controlled environment facilities need engineered HVAC built for stability, redundancy, and precise control. I provide specialty HVAC design, installation, and service for mission-critical applications in my seven daily counties around Kingfisher, backed by 47 years in the trade and 15+ years running my own shop out of Kingfisher.
Telecom & Data Infrastructure HVAC
Telecom and data environments run 24/7 and can’t tolerate temperature swings. My crew designs and services HVAC for telecom sites, computer rooms, and mission-critical facilities where uptime is the whole game.
If that is your main problem, the deeper page is my data center and mission critical cooling page, which covers precision cooling, chilled water plants and redundancy, with photographs from my years on carrier grade work.
- Computer room cooling systems
- Redundant system design
- Temperature and humidity control
- Emergency response availability
Chilled Water & Mechanical Systems
My crew installs and services chilled water systems, pumps, and the mechanical components that tie them together. Proper balancing and controls integration are what separate a system that runs from a system that runs right.
- Pump repair and replacement
- Chilled water piping
- System balancing
- Mechanical room configuration
Controls & Environmental Automation
Modern controlled environments live or die on accurate controls. My crew installs and services automation that regulates temperature, humidity, airflow, and overall system performance.
- Environmental control systems
- Sensor calibration
- System diagnostics
- Controls repair and replacement
Engineered Design & Installation
In partnership with a licensed and bonded engineering firm, I deliver engineered HVAC design and installation. Combined project experience across that partnership exceeds 600,000 cooling tons across multi-state installs.
I’m always looking to add specialized technicians to the crew.
Emergency Response & Scheduled Maintenance
Mission-critical facilities need dependable service. My crew provides emergency call-out support and scheduled maintenance programs built to minimize downtime.
For a consultation on controlled environment or specialty HVAC in Oklahoma, call me at 405-375-4822 to walk through your project.
Ready to Schedule?
Call 405-375-4822 or book online. Same-day appointments often available. Free estimates on new systems.
Nearby Communities I Serve
Frequently Asked Questions
What is controlled environment agriculture (CEA) HVAC?
CEA HVAC is climate control built for indoor growing: precise temperature, humidity, CO2, and airflow at every crop stage. It goes beyond standard commercial HVAC in latent load capacity, control integration, and redundancy.
What humidity levels are needed for indoor cultivation?
Seedling/clone stage: 65 to 70% RH. Vegetative stage: 50 to 70% RH. Flower/fruit stage: 40 to 50% RH. Drying/curing: 45 to 55% RH. My CEA systems use dedicated commercial dehumidifiers instead of relying on cooling-only dehumidification.
Does Hartzell’s design HVAC systems for new grow facilities?
Yes. I provide load calculations, equipment selection, ductwork design, and full installation for new controlled-environment facilities in central Oklahoma. I account for lighting heat loads, occupancy, CO2 enrichment, and future expansion.
Our Job Isn’t Done Until You’re Satisfied
- Your system is running, tested, and set to your preferred temperature
- You understand how to operate your new equipment or thermostat
- The work area is clean, my crew takes our trash with us
- You have documentation for manufacturer warranty and any applicable rebates
- Every question you have is answered before my crew leaves the driveway
Written by Dave Hartzell. Owner, Hartzell’s Heat & Air. Master HVAC License #00115936. 47 years HVAC experience, serving central Oklahoma for 15+ years (~2011).