This free online course will explain the basic concepts and core principles of HVAC systems and their components.

Have you ever looked at an HVAC unit, a thermostat, or a wiring diagram and thought, 'Where do I even start?' This HVAC fundamentals course is built for that moment. If you want practical HVAC technician training without getting lost in jargon, you’ll learn how heating, ventilation, and air conditioning actually work in real homes and small buildings. By the end, you’ll speak the language of HVAC systems, spot common faults faster, and feel confident discussing repairs, maintenance, and upgrades.

You’ll begin with the electrical basics every HVAC pro needs: key terms, safe power concepts, Ohm’s law, and Watt’s law. Then, you’ll tackle the distinction between overload and overcurrent, why each occurs, and how overload and overcurrent protection devices prevent damage. From there, the course breaks down single-phase and three-phase power, as well as low-voltage release (LVR) and low-voltage protection (LVP), so you understand what equipment expects and what happens when voltage drops at the worst possible time. You’ll also pick up quick calculation habits for the field.

Next comes the comfort side of HVAC. You’ll explore domestic heating and cooling techniques, including how thermostats control heating equipment, and learn about common thermostat types and their unique features. Ventilation follows, because airflow is where many systems fail. You’ll learn about pressure terms, fans, blowers, and dampers, as well as how to move air efficiently through ducts and spaces. Finally, you’ll unpack refrigeration principles, thermodynamics, gas pressure laws, and mechanical cooling, connecting refrigerants, evaporation, and energy use to everyday troubleshooting.