HVAC Basics is for HVAC students and working technicians who want clear, practical explanations of how HVAC systems work, without the fluff.
Here you will find theory and troubleshooting lessons: short, image-heavy lessons that explain one idea at a time. Most take 5-10 minutes to read, and build towards the skills you need in the field.
HVAC Basics is written by Jesse, a licensed gas technician working in commercial HVAC. The lessons are based on real systems, real faults, and what actually works in the field.
Start here
If you are new to the site, these guides are a good place to begin:
- The Basic Refrigeration Cycle: How Heat Actually Moves (And What Each Part Does)
- Heat Pump Reversing Valves: How They Work and How to Troubleshoot Them
- Superheat vs. Subcooling: What the Numbers Tell You
- Definitions, a reference for terms used across the lessons.
For hands-on practice, try the The HVAC Game, a first-person troubleshooting simulator.
Browse by topic
- Electricity
- Combustion
- Refrigeration
- Airflow
- HVAC Components
- Sequence of Operation
- Wiring Diagrams
- Helpful Tools