Certified Energy Auditor Certification Building Envelope and Lighting 2 — Questions and Answers
Question 1: Which window property describes the fraction of incident solar radiation that passes through the glazing system as heat?
- Visible transmittance (VT)
- Solar heat gain coefficient (SHGC) (Correct answer)
- U-factor
- Emissivity
Correct answer: Solar heat gain coefficient (SHGC)
Solar heat gain coefficient (SHGC) measures the fraction of solar radiation admitted through a window as heat gain, on a scale of 0 to 1.
Question 2: A building's thermal mass is most beneficial in which climate condition?
- Hot-humid with minimal temperature swings
- Cold climates with long heating seasons
- Hot-dry climates with large diurnal temperature swings (Correct answer)
- Mixed-humid climates with year-round moderate temperatures
Correct answer: Hot-dry climates with large diurnal temperature swings
Thermal mass is most effective in hot-dry climates where large day-night temperature swings allow the mass to absorb heat during the day and release it during cooler nights.
Question 3: What is the primary purpose of a vapor retarder in a wall assembly?
- Improve structural integrity of the wall
- Control the diffusion of water vapor to prevent condensation within the assembly (Correct answer)
- Increase the thermal resistance of insulation
- Reduce air infiltration through the wall cavity
Correct answer: Control the diffusion of water vapor to prevent condensation within the assembly
A vapor retarder limits water vapor diffusion through the building envelope, preventing condensation within the wall assembly that can cause mold and structural damage.
Question 4: In lighting energy audits, what does the term 'lamp lumen depreciation' (LLD) describe?
- The reduction in lamp lumens due to fixture dirt accumulation
- The decrease in lamp light output over its operating life (Correct answer)
- The difference in lumens between rated and actual lamp output
- The loss of lumens caused by ballast inefficiency
Correct answer: The decrease in lamp light output over its operating life
Lamp lumen depreciation (LLD) is the gradual reduction in light output that occurs as a lamp ages over its operating life, used in lighting design calculations.
Question 5: Which insulation material has the highest R-value per inch?
- Fiberglass batt
- Mineral wool batt
- Closed-cell spray polyurethane foam (Correct answer)
- Cellulose blown-in
Correct answer: Closed-cell spray polyurethane foam
Closed-cell spray polyurethane foam provides approximately R-6 to R-7 per inch, the highest thermal resistance per inch of common insulation materials.
Question 6: An energy auditor measures a lighting system's efficacy at 85 lumens per watt. This metric quantifies:
- The ratio of visible light output to total electrical power consumed (Correct answer)
- The color rendering ability of the light source
- The percentage of fixture lumens delivered to the work plane
- The rated life of the lamp in hours
Correct answer: The ratio of visible light output to total electrical power consumed
Luminous efficacy (lumens per watt) measures how efficiently a light source converts electrical energy into visible light output.
Question 7: What does a blower door test primarily measure in a building energy audit?
- Total window area relative to floor area (WWR)
- Duct leakage to the outside
- Overall building air leakage rate (Correct answer)
- Infiltration of moisture through the building envelope
Correct answer: Overall building air leakage rate
A blower door test depressurizes the building to measure the overall air leakage rate, typically expressed as ACH50 or CFM50.
Certified Energy Auditor Certification Building Envelope and Lighting 2
Which window property describes the fraction of incident solar radiation that passes through the glazing system as heat?