NABCEP Solar Heating Installer
Certification Exam With Actual
Questions & Verified Answers, Plus
Explained Rationales/Expert Verified
For Guaranteed Pass 2026/Latest
Updated/Instant Download Pdf
1. Which type of solar collector is most commonly used for domestic
hot water systems?
A. Evacuated tube collector
B. Flat-plate collector
C. Parabolic trough
D. Dish concentrator
B. Flat-plate collector
Flat-plate collectors are widely used for domestic hot water because
they are cost-effective, durable, and efficient for low- to medium-
temperature applications.
2. What is the primary function of a solar storage tank in a solar
water heating system?
A. Increase water pressure
B. Store thermal energy
C. Heat water directly with electricity
D. Filter impurities
,B. Store thermal energy
The storage tank stores hot water collected from the solar collector,
allowing use when sunlight is not available.
3. What type of fluid is typically used in closed-loop solar water
heating systems to prevent freezing?
A. Tap water
B. Ethylene glycol solution
C. Diesel fuel
D. Sodium hydroxide
B. Ethylene glycol solution
Closed-loop systems use a heat-transfer fluid like ethylene glycol to
prevent freezing and corrosion within the system.
4. In a thermosiphon solar water heating system, water circulates
primarily due to:
A. Electric pumps
B. Gravity and natural convection
C. Manual operation
D. Wind power
B. Gravity and natural convection
Thermosiphon systems rely on the natural movement of hot water
rising and cold water sinking to circulate fluid.
5. What is the main advantage of evacuated tube collectors over
flat-plate collectors?
A. Lower cost
B. Better efficiency in cold or cloudy conditions
C. Simpler installation
D. Less maintenance
,B. Better efficiency in cold or cloudy conditions
Evacuated tube collectors have better insulation and can maintain
higher efficiency in low ambient temperatures and diffuse sunlight.
6. Which solar water heating system configuration is most suitable
for areas with freezing temperatures?
A. Open-loop
B. Drainback or closed-loop
C. Direct-flow thermosiphon
D. Batch system
B. Drainback or closed-loop
These systems prevent freezing by using antifreeze fluids or by
draining water from the collector when not in use.
7. What is the purpose of a heat exchanger in a solar water heating
system?
A. Reduce water pressure
B. Transfer heat from the collector fluid to potable water
C. Increase sunlight absorption
D. Prevent water from boiling
B. Transfer heat from the collector fluid to potable water
A heat exchanger allows thermal energy from the solar fluid to heat
potable water without mixing the fluids.
8. Which factor most directly affects the efficiency of a solar
collector?
A. Pipe color
B. Collector orientation and tilt
C. Type of water tank
D. Distance from utility grid
, B. Collector orientation and tilt
Collectors must face the sun optimally and be angled appropriately to
maximize solar radiation absorption.
9. What is the recommended tilt angle for a fixed flat-plate solar
collector in mid-latitude regions?
A. Horizontal
B. Equal to the latitude of the location
C. Vertical
D. 90° minus latitude
B. Equal to the latitude of the location
Tilting the collector at an angle approximately equal to the local
latitude optimizes annual solar gain.
10. Which type of pump is most commonly used in active solar
water heating systems?
A. Centrifugal pump
B. Reciprocating pump
C. Axial pump
D. Positive displacement pump
A. Centrifugal pump
Centrifugal pumps are reliable and cost-effective for circulating solar
fluids in active systems.
11. What is the main reason for installing a pressure relief valve
on a solar storage tank?
A. Improve heating efficiency
B. Prevent excessive pressure buildup
C. Regulate water flow
D. Increase solar absorption
Certification Exam With Actual
Questions & Verified Answers, Plus
Explained Rationales/Expert Verified
For Guaranteed Pass 2026/Latest
Updated/Instant Download Pdf
1. Which type of solar collector is most commonly used for domestic
hot water systems?
A. Evacuated tube collector
B. Flat-plate collector
C. Parabolic trough
D. Dish concentrator
B. Flat-plate collector
Flat-plate collectors are widely used for domestic hot water because
they are cost-effective, durable, and efficient for low- to medium-
temperature applications.
2. What is the primary function of a solar storage tank in a solar
water heating system?
A. Increase water pressure
B. Store thermal energy
C. Heat water directly with electricity
D. Filter impurities
,B. Store thermal energy
The storage tank stores hot water collected from the solar collector,
allowing use when sunlight is not available.
3. What type of fluid is typically used in closed-loop solar water
heating systems to prevent freezing?
A. Tap water
B. Ethylene glycol solution
C. Diesel fuel
D. Sodium hydroxide
B. Ethylene glycol solution
Closed-loop systems use a heat-transfer fluid like ethylene glycol to
prevent freezing and corrosion within the system.
4. In a thermosiphon solar water heating system, water circulates
primarily due to:
A. Electric pumps
B. Gravity and natural convection
C. Manual operation
D. Wind power
B. Gravity and natural convection
Thermosiphon systems rely on the natural movement of hot water
rising and cold water sinking to circulate fluid.
5. What is the main advantage of evacuated tube collectors over
flat-plate collectors?
A. Lower cost
B. Better efficiency in cold or cloudy conditions
C. Simpler installation
D. Less maintenance
,B. Better efficiency in cold or cloudy conditions
Evacuated tube collectors have better insulation and can maintain
higher efficiency in low ambient temperatures and diffuse sunlight.
6. Which solar water heating system configuration is most suitable
for areas with freezing temperatures?
A. Open-loop
B. Drainback or closed-loop
C. Direct-flow thermosiphon
D. Batch system
B. Drainback or closed-loop
These systems prevent freezing by using antifreeze fluids or by
draining water from the collector when not in use.
7. What is the purpose of a heat exchanger in a solar water heating
system?
A. Reduce water pressure
B. Transfer heat from the collector fluid to potable water
C. Increase sunlight absorption
D. Prevent water from boiling
B. Transfer heat from the collector fluid to potable water
A heat exchanger allows thermal energy from the solar fluid to heat
potable water without mixing the fluids.
8. Which factor most directly affects the efficiency of a solar
collector?
A. Pipe color
B. Collector orientation and tilt
C. Type of water tank
D. Distance from utility grid
, B. Collector orientation and tilt
Collectors must face the sun optimally and be angled appropriately to
maximize solar radiation absorption.
9. What is the recommended tilt angle for a fixed flat-plate solar
collector in mid-latitude regions?
A. Horizontal
B. Equal to the latitude of the location
C. Vertical
D. 90° minus latitude
B. Equal to the latitude of the location
Tilting the collector at an angle approximately equal to the local
latitude optimizes annual solar gain.
10. Which type of pump is most commonly used in active solar
water heating systems?
A. Centrifugal pump
B. Reciprocating pump
C. Axial pump
D. Positive displacement pump
A. Centrifugal pump
Centrifugal pumps are reliable and cost-effective for circulating solar
fluids in active systems.
11. What is the main reason for installing a pressure relief valve
on a solar storage tank?
A. Improve heating efficiency
B. Prevent excessive pressure buildup
C. Regulate water flow
D. Increase solar absorption
