South Carolina Residential HVAC
Contractor Exam Practice Questions
And Correct Answers (Verified
Answers) Plus Rationale 2027 Q&A|
Instant Download Pdf.
1. A residential HVAC system is being installed in a South Carolina
dwelling. Which method is most appropriate for determining the
required heating and cooling capacity before selecting the
equipment?
A. Use the largest equipment commonly installed in similar homes
B. Select equipment based only on the square footage of the home
C. Perform a recognized residential heating and cooling load calculation
D. Match the equipment size to the electrical service rating
C. Perform a recognized residential heating and cooling load calculation
A proper load calculation accounts for building characteristics, climate,
orientation, insulation, windows, occupancy, infiltration, and other heat
gains and losses. Oversizing equipment solely from square footage can
produce poor comfort, humidity control, and efficiency.
, 2. In residential HVAC design, what is the primary purpose of
insulation on a supply-air duct passing through an unconditioned
attic?
A. To increase the static pressure of the duct
B. To reduce heat transfer between the air inside the duct and the
surrounding space
C. To increase the velocity of air through the duct
D. To eliminate the need for duct sealing
B. To reduce heat transfer between the air inside the duct and the
surrounding space
Duct insulation reduces unwanted heat gain or heat loss and helps the
conditioned air remain closer to its intended supply temperature. It does
not replace proper duct sealing.
3. When supporting a residential HVAC duct system, which practice is
most important?
A. Allow the duct to rest directly on ceiling insulation
B. Support the duct adequately so that its shape and integrity are
maintained
C. Suspend the duct only from electrical wiring
D. Use combustible materials regardless of the duct location
B. Support the duct adequately so that its shape and integrity are
maintained
,Proper hangers and supports prevent sagging, deformation, separation,
and excessive loading of connections. HVAC supports must be
appropriate for the duct construction and installation conditions.
4. A flexible duct is installed with excessive bends and sharp turns.
What is the most likely result?
A. Reduced airflow and increased resistance
B. Increased cooling capacity
C. Lower system static pressure
D. Improved air distribution
A. Reduced airflow and increased resistance
Sharp bends and excessive flex-duct compression increase friction and
turbulence, reducing airflow and potentially causing inadequate heating
or cooling at occupied spaces.
5. Which heat-transfer process involves energy moving through a solid
material from a warmer region toward a cooler region?
A. Radiation
B. Convection
C. Conduction
D. Evaporation
C. Conduction
Conduction is heat transfer through a material caused by molecular
interaction. Convection involves fluid movement, while radiation
transfers energy by electromagnetic waves.
, 6. In a typical vapor-compression air-conditioning system, which
component removes heat from the conditioned indoor space?
A. Evaporator
B. Condenser
C. Compressor
D. Receiver
A. Evaporator
The evaporator absorbs heat from the indoor air as refrigerant
evaporates within the coil. The condenser subsequently rejects that
absorbed heat and compressor heat to the outdoor environment.
7. What is the primary function of the compressor in a vapor-
compression refrigeration cycle?
A. Lower the refrigerant pressure entering the evaporator
B. Circulate refrigerant by compressing low-pressure vapor into higher-
pressure vapor
C. Convert high-pressure liquid directly into low-pressure liquid
D. Remove moisture from the conditioned air
B. Circulate refrigerant by compressing low-pressure vapor into higher-
pressure vapor
The compressor raises the pressure and temperature of refrigerant
vapor and drives refrigerant circulation through the refrigeration
system.
Contractor Exam Practice Questions
And Correct Answers (Verified
Answers) Plus Rationale 2027 Q&A|
Instant Download Pdf.
1. A residential HVAC system is being installed in a South Carolina
dwelling. Which method is most appropriate for determining the
required heating and cooling capacity before selecting the
equipment?
A. Use the largest equipment commonly installed in similar homes
B. Select equipment based only on the square footage of the home
C. Perform a recognized residential heating and cooling load calculation
D. Match the equipment size to the electrical service rating
C. Perform a recognized residential heating and cooling load calculation
A proper load calculation accounts for building characteristics, climate,
orientation, insulation, windows, occupancy, infiltration, and other heat
gains and losses. Oversizing equipment solely from square footage can
produce poor comfort, humidity control, and efficiency.
, 2. In residential HVAC design, what is the primary purpose of
insulation on a supply-air duct passing through an unconditioned
attic?
A. To increase the static pressure of the duct
B. To reduce heat transfer between the air inside the duct and the
surrounding space
C. To increase the velocity of air through the duct
D. To eliminate the need for duct sealing
B. To reduce heat transfer between the air inside the duct and the
surrounding space
Duct insulation reduces unwanted heat gain or heat loss and helps the
conditioned air remain closer to its intended supply temperature. It does
not replace proper duct sealing.
3. When supporting a residential HVAC duct system, which practice is
most important?
A. Allow the duct to rest directly on ceiling insulation
B. Support the duct adequately so that its shape and integrity are
maintained
C. Suspend the duct only from electrical wiring
D. Use combustible materials regardless of the duct location
B. Support the duct adequately so that its shape and integrity are
maintained
,Proper hangers and supports prevent sagging, deformation, separation,
and excessive loading of connections. HVAC supports must be
appropriate for the duct construction and installation conditions.
4. A flexible duct is installed with excessive bends and sharp turns.
What is the most likely result?
A. Reduced airflow and increased resistance
B. Increased cooling capacity
C. Lower system static pressure
D. Improved air distribution
A. Reduced airflow and increased resistance
Sharp bends and excessive flex-duct compression increase friction and
turbulence, reducing airflow and potentially causing inadequate heating
or cooling at occupied spaces.
5. Which heat-transfer process involves energy moving through a solid
material from a warmer region toward a cooler region?
A. Radiation
B. Convection
C. Conduction
D. Evaporation
C. Conduction
Conduction is heat transfer through a material caused by molecular
interaction. Convection involves fluid movement, while radiation
transfers energy by electromagnetic waves.
, 6. In a typical vapor-compression air-conditioning system, which
component removes heat from the conditioned indoor space?
A. Evaporator
B. Condenser
C. Compressor
D. Receiver
A. Evaporator
The evaporator absorbs heat from the indoor air as refrigerant
evaporates within the coil. The condenser subsequently rejects that
absorbed heat and compressor heat to the outdoor environment.
7. What is the primary function of the compressor in a vapor-
compression refrigeration cycle?
A. Lower the refrigerant pressure entering the evaporator
B. Circulate refrigerant by compressing low-pressure vapor into higher-
pressure vapor
C. Convert high-pressure liquid directly into low-pressure liquid
D. Remove moisture from the conditioned air
B. Circulate refrigerant by compressing low-pressure vapor into higher-
pressure vapor
The compressor raises the pressure and temperature of refrigerant
vapor and drives refrigerant circulation through the refrigeration
system.
