California HVAC Contractor (C-20) License
Exam | COMPREHENSIVE EXAM WITH
CORRECT VERIFIED ANSWERS AND
RATIONALES. ALREADY GRADED A+
1. The primary purpose of an HVAC system is to:
A. Provide heating, ventilation, and air conditioning ✅
B. Filter water
C. Supply electricity
D. Measure gas pressure
Rationale: HVAC systems control indoor climate for comfort
and safety.
2. Which refrigerant is commonly used in residential AC
systems?
A. R-410A ✅
B. R-22 only
C. R-134 only
D. Ammonia
Rationale: R-410A is widely adopted due to ozone-friendly
properties.
3. A heat pump can:
A. Provide both heating and cooling ✅
,B. Only heat
C. Only cool
D. Filter air
Rationale: Heat pumps reverse cycle to provide heating in
winter and cooling in summer.
4. What is the purpose of an expansion valve in a
refrigeration system?
A. Regulate refrigerant flow into the evaporator ✅
B. Increase pressure in the condenser
C. Heat air
D. Vent gases
Rationale: Expansion valves control the amount of
refrigerant entering the evaporator.
5. SEER stands for:
A. Seasonal Energy Efficiency Ratio ✅
B. Standard Electric Efficiency Rating
C. System Energy Evaluation Ratio
D. Solar Energy Efficiency Ratio
Rationale: SEER measures cooling efficiency over a season.
6. Which type of HVAC system uses ducts to distribute air?
A. Forced-air system ✅
,B. Radiant heating
C. Geothermal
D. Window AC unit
Rationale: Ducts carry conditioned air to multiple zones in a
building.
7. A common cause of low airflow in an HVAC system is:
A. Dirty air filters ✅
B. Excess refrigerant
C. High SEER rating
D. Oversized ducts
Rationale: Clogged filters reduce airflow and system
efficiency.
8. What is the function of a thermostat?
A. Regulate indoor temperature ✅
B. Measure humidity
C. Vent gases
D. Heat water
Rationale: Thermostats control HVAC system operation
based on temperature setpoints.
9. The purpose of a condenser coil is to:
A. Release heat from the refrigerant ✅
, B. Absorb heat from indoor air
C. Filter dust
D. Regulate airflow
Rationale: Condenser coils expel heat absorbed from inside
the building.
10. Evaporator coils are located:
A. Indoors ✅
B. Outdoors
C. In the furnace only
D. In the attic only
Rationale: Evaporator coils absorb heat from indoor air.
11. A common refrigerant leak indicator is:
A. Oil stains near joints ✅
B. High airflow
C. Cold duct surfaces
D. Low SEER rating
Rationale: Leaks often leave oil traces from the compressor
lubricant.
12. HVAC zoning is used to:
A. Control temperature in different areas separately ✅
Exam | COMPREHENSIVE EXAM WITH
CORRECT VERIFIED ANSWERS AND
RATIONALES. ALREADY GRADED A+
1. The primary purpose of an HVAC system is to:
A. Provide heating, ventilation, and air conditioning ✅
B. Filter water
C. Supply electricity
D. Measure gas pressure
Rationale: HVAC systems control indoor climate for comfort
and safety.
2. Which refrigerant is commonly used in residential AC
systems?
A. R-410A ✅
B. R-22 only
C. R-134 only
D. Ammonia
Rationale: R-410A is widely adopted due to ozone-friendly
properties.
3. A heat pump can:
A. Provide both heating and cooling ✅
,B. Only heat
C. Only cool
D. Filter air
Rationale: Heat pumps reverse cycle to provide heating in
winter and cooling in summer.
4. What is the purpose of an expansion valve in a
refrigeration system?
A. Regulate refrigerant flow into the evaporator ✅
B. Increase pressure in the condenser
C. Heat air
D. Vent gases
Rationale: Expansion valves control the amount of
refrigerant entering the evaporator.
5. SEER stands for:
A. Seasonal Energy Efficiency Ratio ✅
B. Standard Electric Efficiency Rating
C. System Energy Evaluation Ratio
D. Solar Energy Efficiency Ratio
Rationale: SEER measures cooling efficiency over a season.
6. Which type of HVAC system uses ducts to distribute air?
A. Forced-air system ✅
,B. Radiant heating
C. Geothermal
D. Window AC unit
Rationale: Ducts carry conditioned air to multiple zones in a
building.
7. A common cause of low airflow in an HVAC system is:
A. Dirty air filters ✅
B. Excess refrigerant
C. High SEER rating
D. Oversized ducts
Rationale: Clogged filters reduce airflow and system
efficiency.
8. What is the function of a thermostat?
A. Regulate indoor temperature ✅
B. Measure humidity
C. Vent gases
D. Heat water
Rationale: Thermostats control HVAC system operation
based on temperature setpoints.
9. The purpose of a condenser coil is to:
A. Release heat from the refrigerant ✅
, B. Absorb heat from indoor air
C. Filter dust
D. Regulate airflow
Rationale: Condenser coils expel heat absorbed from inside
the building.
10. Evaporator coils are located:
A. Indoors ✅
B. Outdoors
C. In the furnace only
D. In the attic only
Rationale: Evaporator coils absorb heat from indoor air.
11. A common refrigerant leak indicator is:
A. Oil stains near joints ✅
B. High airflow
C. Cold duct surfaces
D. Low SEER rating
Rationale: Leaks often leave oil traces from the compressor
lubricant.
12. HVAC zoning is used to:
A. Control temperature in different areas separately ✅
