Beginner Path

Start from zero: heat, temperature, pressure, the refrigeration cycle, airflow and basic electricity.

1. 01Temperature and Heat
   Concept
   Temperature measures intensity, heat measures quantity. Confusing the two is the root of many bad diagnoses.
2. 02Heat Transfer
   Concept
   Conduction, convection and radiation, and why every HVAC system is really a heat moving machine.
3. 03Sensible and Latent Heat
   Concept
   The difference between heat you can measure with a thermometer and heat that removes moisture from the air.
4. 04States of Matter and Phase Change
   Concept
   Why refrigeration uses boiling and condensing rather than simply moving warm and cold fluid around.
5. 05Pressure and Temperature Relationship
   Concept
   Why a pressure reading tells you a saturation temperature, and how technicians use that link every day.
6. 06The Refrigeration Cycle
   Concept
   How a vapor compression system moves heat from where it is not wanted to where it can be rejected.
7. 07Airflow Fundamentals
   Concept
   CFM, static pressure and why airflow problems are behind a large share of service calls.
8. 08Electricity Fundamentals
   Concept
   Voltage, current, resistance and power, and how they show up in HVAC line and control circuits.
9. 09Ohm's Law and the Power Formula
   Concept
   The arithmetic behind every electrical reading you take, and how to use it to predict what a meter should show.
10. 10Air Conditioner
    Equipment
    A split system cooling appliance: what each half does and how the two halves have to match.
11. 11Gas Furnace
    Equipment
    How a modern forced air gas furnace proves each condition before it allows the next step.
12. 12Heat Pump
    Equipment
    The same refrigeration cycle, reversed on demand, so one machine can heat and cool.