NABCEP Solar Heating Installer
Certification Practice Exam Questions
And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant
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1. What is the primary function of a solar thermal collector?
A. Store energy for later use
B. Convert sunlight into electricity
C. Absorb solar radiation and transfer it to a fluid
D. Generate mechanical energy from sunlight
Rationale: Solar thermal collectors capture solar energy and transfer
it to a fluid for heating purposes, not electricity generation.
2. Which type of solar thermal collector is most efficient in high-
temperature applications?
A. Flat-plate collector
B. Evacuated tube collector
, C. Unglazed collector
D. Concentrating photovoltaic collector
Rationale: Evacuated tube collectors reduce heat loss and are
effective for high-temperature water or space heating.
3. What is the main purpose of a heat exchanger in a solar water heating
system?
A. Store thermal energy
B. Transfer heat from the solar loop to the domestic water loop
C. Pump fluid through the collector
D. Convert heat into electricity
Rationale: Heat exchangers allow heat transfer without mixing
fluids, protecting potable water from contamination.
4. Which type of solar water heating system stores water in the tank
above the collector?
A. Thermosiphon system
B. Pumped closed-loop system
C. Drainback system
D. Direct circulation system
Rationale: Thermosiphon systems rely on natural convection; hot
water rises into the storage tank located above the collector.
5. What is the purpose of a solar system controller?
A. Measure solar radiation
B. Manage pump operation to optimize energy transfer
, C. Store heat in the tank
D. Protect the roof from water damage
Rationale: Controllers operate pumps based on temperature sensors
to maximize system efficiency.
6. Which antifreeze is commonly used in closed-loop solar thermal
systems?
A. Ethanol
B. Propylene glycol
C. Mineral oil
D. Methanol
Rationale: Propylene glycol is non-toxic and protects against freezing
in closed-loop systems.
7. What is the recommended slope for a flat-plate solar collector in most
U.S. locations?
A. 10–20 degrees
B. Equal to latitude ±10 degrees
C. 45–60 degrees
D. Horizontal only
Rationale: Aligning collector slope with local latitude optimizes year-
round solar gain.
8. What is the typical efficiency range of a modern flat-plate collector?
A. 10–20%
B. 30–40%
, C. 40–70%
D. 80–90%
Rationale: Modern flat-plate collectors efficiently convert 40–70% of
solar energy into usable heat.
9. Which component protects a closed-loop solar system from
overpressure?
A. Expansion tank
B. Pressure relief valve
C. Check valve
D. Flow meter
Rationale: Pressure relief valves prevent dangerous pressure buildup
in closed-loop systems.
10. What is the main cause of collector stagnation?
A. Pump failure
B. High solar radiation with no heat removal
C. Low fluid temperature
D. Low solar radiation
Rationale: Stagnation occurs when collectors overheat due to
insufficient fluid flow to remove absorbed heat.
11. In a drainback system, what happens when the pump stops?
A. Fluid remains in collectors
B. Fluid drains back into the tank
C. Heat exchanger freezes
Certification Practice Exam Questions
And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant
Download Pdf
1. What is the primary function of a solar thermal collector?
A. Store energy for later use
B. Convert sunlight into electricity
C. Absorb solar radiation and transfer it to a fluid
D. Generate mechanical energy from sunlight
Rationale: Solar thermal collectors capture solar energy and transfer
it to a fluid for heating purposes, not electricity generation.
2. Which type of solar thermal collector is most efficient in high-
temperature applications?
A. Flat-plate collector
B. Evacuated tube collector
, C. Unglazed collector
D. Concentrating photovoltaic collector
Rationale: Evacuated tube collectors reduce heat loss and are
effective for high-temperature water or space heating.
3. What is the main purpose of a heat exchanger in a solar water heating
system?
A. Store thermal energy
B. Transfer heat from the solar loop to the domestic water loop
C. Pump fluid through the collector
D. Convert heat into electricity
Rationale: Heat exchangers allow heat transfer without mixing
fluids, protecting potable water from contamination.
4. Which type of solar water heating system stores water in the tank
above the collector?
A. Thermosiphon system
B. Pumped closed-loop system
C. Drainback system
D. Direct circulation system
Rationale: Thermosiphon systems rely on natural convection; hot
water rises into the storage tank located above the collector.
5. What is the purpose of a solar system controller?
A. Measure solar radiation
B. Manage pump operation to optimize energy transfer
, C. Store heat in the tank
D. Protect the roof from water damage
Rationale: Controllers operate pumps based on temperature sensors
to maximize system efficiency.
6. Which antifreeze is commonly used in closed-loop solar thermal
systems?
A. Ethanol
B. Propylene glycol
C. Mineral oil
D. Methanol
Rationale: Propylene glycol is non-toxic and protects against freezing
in closed-loop systems.
7. What is the recommended slope for a flat-plate solar collector in most
U.S. locations?
A. 10–20 degrees
B. Equal to latitude ±10 degrees
C. 45–60 degrees
D. Horizontal only
Rationale: Aligning collector slope with local latitude optimizes year-
round solar gain.
8. What is the typical efficiency range of a modern flat-plate collector?
A. 10–20%
B. 30–40%
, C. 40–70%
D. 80–90%
Rationale: Modern flat-plate collectors efficiently convert 40–70% of
solar energy into usable heat.
9. Which component protects a closed-loop solar system from
overpressure?
A. Expansion tank
B. Pressure relief valve
C. Check valve
D. Flow meter
Rationale: Pressure relief valves prevent dangerous pressure buildup
in closed-loop systems.
10. What is the main cause of collector stagnation?
A. Pump failure
B. High solar radiation with no heat removal
C. Low fluid temperature
D. Low solar radiation
Rationale: Stagnation occurs when collectors overheat due to
insufficient fluid flow to remove absorbed heat.
11. In a drainback system, what happens when the pump stops?
A. Fluid remains in collectors
B. Fluid drains back into the tank
C. Heat exchanger freezes
