Less Guesswork. Better Diagnostics. Fewer Callbacks.
Training that works when the boots hit the ground
Trusted By Industry Experts
About Don Gillis
With over 33 years in the HVACR industry, I’ve spent 25 of those years in the field as a licensed journeyman, working on the same systems and challenges technicians face every day.
My background includes roles as a service technician, service manager, and international trainer. I’ve had the opportunity to help train thousands of technicians, distributors, OEMs, and HVAC professionals across the country. And was voted in the Top 25 Most Influential Educators in 2024 by ESCO.
My goal is simple: deliver practical, real-world training that helps people understand the system, make better decisions, and get the job done right
What's Behind my mission
The mission of Gillis Coach is to provide practical, high-quality HVACR education that strengthens technical knowledge, improves field performance, promotes safe and code-compliant work, and supports the professional growth of contractors, technicians, installers, and industry personnel. Through real-world instruction, current industry practices, and clear, experience-based training,
Target Audience
Who This Is For
Bridging the gap for professionals across every level of the HVACR ecosystem.
HVAC Technicans
Customized field training designed to reduce call-backs, improve technician retention, and increase overall service profitability.
Train the Trainer
Empowering your internal leaders with the tools and teaching techniques to deliver high-impact technical training themselves.
Counter People
The counter is where the job either goes smoothly or goes sideways. We train your counter staff to know the parts beyond just the SKU.
OEM Partners
Partnering with manufacturers to deliver specialized training that ensures proper field installation and reduces warranty claims.
Tech Support Mastery
Textbooks don’t sweat on a rooftop. This training is built by someone who’s been in the field, for people who work in the field.
Certified. Licensed. Trusted.
Official documentation of training completion and field
Certificate of Completion
HVACR Journeyman License
Trusted technician driven knowledge
Real-World HVACR Technical Training
HVACR Basics
Understand What the System Is Doing
Refrigeration, heat transfer, pressure-temperature relationships, superheat, subcooling, airflow, electrical fundamentals, and system operation—explained in practical field language.
System Diagnostics
Stop Guessing. Start Proving.
Learn how to read the entire system before replacing parts. Use temperatures, pressures, airflow, voltage, amperage, and system history to find the actual problem.
Compressors & Parts
Know What Fails—and Why Compressors, motors, controls, metering devices, contactors, capacitors, valves, boards, and system components. Understand their purpose, operation, common failures, and proper testing.
Airflow and System Performance
Airflow Before Refrigerant Static pressure, blower performance, duct restrictions, filters, coils, registers, temperature rise, and system capacity. Learn how airflow problems affect every part of the system.
Modern Equipment and Refrigerants
Training for the Equipment Technicians Face Today Heat pumps, inverter systems, variable-speed equipment, A2L refrigerants, electronic controls, communicating systems, and the changing HVACR industry.
Technician and Contractor Development
Training Built Around Your Team Programs for installers, service technicians, senior technicians, counter personnel, sales teams, trainers, and contractors. Every course can be adjusted to your equipment, market, and experience level.
Testimonials
I met Don nearly five years ago at the HVAC School Training Symposium. Since then, I have relied on him several times for technical advice. His expertise and willingness to share have helped me refine the curriculum at NCI. Don has earned his reputation through years of fieldwork and his dedication to industry education. He communicates complex topics in a way that is relatable to his audience. I consider Don both a friend and mentor. He is one of the most effective and well- spoken presenters I’ve had the opportunity to work with. Whenever I have a question, I know Don will answer the phone when needed.
What makes Don Gillis’ instruction valuable is his sincere and candid presentation. Don has personally experienced his subject matter from the ground up and that’s what adds relevance. Don Gillis is a gifted educator and story-teller. His clients benefit because his content is effective and applicable
Don has been an invaluable asset to the University of Northwestern Ohio and a trusted colleague for many years. As a longstanding member of our HVAC/R Advisory Board, he has consistently provided valuable industry updates, training, and expertise that have greatly benefited the university, our students, and fellow board members. Don has always been willing to assist in locating important information, offer thoughtful guidance, and provide knowledgeable advice whenever needed.
I’ve known Don for over six years in the HVAC industry, and he consistently goes above and beyond to help others succeed. He’s trained thousands across our organization on major industry changes and has helped create content that’s reached hundreds of thousands. Don is extremely knowledgeable, honest, and someone I trust without hesitation.
I’ve had the pleasure of attending multiple classes led by Don Gillis, and each experience has reinforced just how exceptional he is as both an educator and an industry professional. His ability to break down complex technical concepts into clear, practical insights makes his sessions incredibly valuable for both new and experienced professionals.
Frequently Asked Questions
I specialize in technical training for technicians, sales development, and specialized OEM programs.
Yes, all training programs can be tailored to meet the specific technical and business needs of your organization.
I offer both on-site hands-on training and interactive virtual sessions to ensure flexible learning options.
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