Certified Energy Auditor Certification Building Envelope and Lighting 5 — Questions and Answers
Question 1: What is the thermal resistance (R-value) equivalent of a U-factor of 0.25 BTU/hr·ft²·°F?
- R-2.5
- R-4.0 (Correct answer)
- R-6.25
- R-0.25
Correct answer: R-4.0
R-value = 1 ÷ U-factor = 1 ÷ 0.25 = 4.0; R-value and U-factor are reciprocals of each other.
Question 2: Which lighting application is best suited for T5HO fluorescent lamps rather than standard T8 lamps?
- Office task lighting at standard ceiling heights
- Exit signs and emergency lighting
- High-bay industrial spaces with ceilings above 20 feet (Correct answer)
- Residential recessed downlighting
Correct answer: High-bay industrial spaces with ceilings above 20 feet
T5HO (high output) lamps produce significantly more light output per lamp, making them well-suited for high-bay industrial applications where longer throw distances are needed.
Question 3: Slab-on-grade edge insulation is primarily intended to reduce heat loss through:
- Conduction through the concrete slab to the ground below
- Convection along the slab surface to interior air
- Conduction through the slab perimeter exposed to outdoor temperatures (Correct answer)
- Radiation from the slab surface to the interior space
Correct answer: Conduction through the slab perimeter exposed to outdoor temperatures
Slab perimeter (edge) insulation addresses conduction losses at the slab edge where the concrete is directly exposed to cold outdoor temperatures, which is the primary heat loss path.
Question 4: Which metric is used to quantify the air leakage performance of windows and doors under standardized test conditions?
- Solar heat gain coefficient (SHGC)
- Visible transmittance (VT)
- Air leakage rate (AL) in CFM/ft² (Correct answer)
- Condensation resistance (CR)
Correct answer: Air leakage rate (AL) in CFM/ft²
Air leakage rate (AL), expressed in CFM per square foot of frame area at a standard pressure difference, is the NFRC metric for rating window and door airtightness.
Question 5: A building has 200 fixtures each with two 32W T8 lamps and 88% efficient ballasts. What is the actual connected lighting load?
- 12.8 kW
- 14.5 kW (Correct answer)
- 12,800 W
- 14,545 W
Correct answer: 14.5 kW
Total lamp wattage = 200 × 2 × 32W = 12,800W; ballast factor increases this: 12,800W ÷ 0.88 = 14,545W ≈ 14.5 kW.
Question 6: Which of the following best describes 'thermal comfort' as it relates to building envelope performance?
- Maintaining indoor air temperature at exactly 72°F year-round
- Ensuring occupants are not exposed to uncomfortable radiant temperature asymmetry from cold surfaces (Correct answer)
- Providing uniform ventilation to all occupied spaces
- Limiting relative humidity to below 30% in all seasons
Correct answer: Ensuring occupants are not exposed to uncomfortable radiant temperature asymmetry from cold surfaces
Thermal comfort is significantly affected by radiant temperature asymmetry from cold windows or walls, which can cause discomfort even when air temperatures are in the comfort range.
Question 7: When performing an infrared thermographic scan of a building envelope, what condition produces the clearest and most reliable results?
- Scanning on a sunny day with solar radiation heating the exterior surface
- A temperature difference of at least 10°F between interior and exterior surfaces (Correct answer)
- Scanning during high wind conditions to eliminate surface boundary layers
- Performing the scan at midday when temperature differences are greatest
Correct answer: A temperature difference of at least 10°F between interior and exterior surfaces
Infrared thermography requires a minimum delta-T of at least 10°F (ideally 15-18°F) between interior and exterior to produce sufficient heat flow through the envelope for reliable anomaly detection.
Certified Energy Auditor Certification Building Envelope and Lighting 5
What is the thermal resistance (R-value) equivalent of a U-factor of 0.25 BTU/hr·ft²·°F?