Certified Energy Auditor Certification Certified Energy Auditor Data Collection and Analysis 1 — Questions and Answers
Question 1: An energy auditor calculates an office building's Energy Use Intensity (EUI) as 95 kBtu/sq ft/year. The national median EUI for office buildings is 69 kBtu/sq ft/year. What does this comparison most accurately indicate?
- The building is performing better than the national average
- The building consumes approximately 38% more energy per square foot than the median (Correct answer)
- The building qualifies for ENERGY STAR certification
- The building's energy consumption is within acceptable variance for its climate zone
Correct answer: The building consumes approximately 38% more energy per square foot than the median
EUI is calculated as total energy consumed divided by gross floor area. Comparing the building's EUI of 95 to the median of 69 shows a (95-69)/69 ≈ 37.7% excess, indicating the building uses significantly more energy per square foot than a typical comparable facility and is a strong candidate for efficiency improvements.
Question 2: While analyzing 15-minute interval electricity demand data, an auditor identifies sustained consumption of 120 kW between midnight and 5 AM on weekdays when the building is unoccupied. What is the most likely explanation for this pattern?
- Normal HVAC morning pre-conditioning warm-up cycles
- Equipment or systems operating unnecessarily during unoccupied hours (Correct answer)
- Peak demand charges being assessed by the utility
- Accurate sub-metering of emergency lighting circuits
Correct answer: Equipment or systems operating unnecessarily during unoccupied hours
Sustained load during unoccupied hours typically indicates systems such as HVAC, process equipment, or plug loads that are not being shut down or scheduled properly. This 'baseload creep' during vacancy is a key finding in interval data analysis and represents a prime opportunity for operational savings.
Question 3: An auditor uses ENERGY STAR Portfolio Manager to benchmark a commercial office building. What does a Portfolio Manager score of 75 signify?
- The building uses 75% of the energy of an average comparable building
- The building performs better than 75% of similar buildings nationally, adjusting for operational characteristics (Correct answer)
- The building has achieved a 25% reduction from its own historical baseline
- The building meets the minimum threshold for LEED energy credits
Correct answer: The building performs better than 75% of similar buildings nationally, adjusting for operational characteristics
ENERGY STAR Portfolio Manager scores are percentile rankings from 1 to 100. A score of 75 means the building outperforms 75% of similar facilities nationwide after normalizing for weather, operating hours, occupancy, and other relevant variables. A score of 75 or above is required to apply for ENERGY STAR certification.
Question 4: During utility bill analysis, an auditor finds that demand charges account for 48% of a manufacturing facility's monthly electricity costs. Which data collection step should the auditor prioritize next?
- Obtain 12 additional months of historical bills to extend the baseline period
- Collect interval demand data to identify the timing and sources of peak demand events (Correct answer)
- Install sub-meters on the lighting distribution panels
- Calculate the building's power factor from nameplate equipment data
Correct answer: Collect interval demand data to identify the timing and sources of peak demand events
When demand charges represent a large share of electricity costs, identifying when and why peak demand spikes occur is the highest-value analytical step. Interval demand data (typically 15-minute readings) reveals which systems or events drive peak demand, enabling targeted load-shedding, load-shifting, or demand-control strategies that can yield significant bill reductions.
Question 5: An auditor collects nameplate data from a rooftop HVAC unit and finds the installed cooling capacity is 60 tons. A peak load calculation for the served zone yields 18 tons. What does this finding most directly indicate?
- The system has appropriate redundancy for a critical cooling application
- The equipment is significantly oversized, likely causing short-cycling and degraded efficiency (Correct answer)
- Cooling capacity is adequate and no further analysis is needed
- Additional cooling units should be recommended to handle future load growth
Correct answer: The equipment is significantly oversized, likely causing short-cycling and degraded efficiency
A capacity-to-load ratio of more than 3:1 indicates severe oversizing. Oversized cooling equipment short-cycles — it satisfies the thermostat setpoint quickly and shuts off before completing a full dehumidification cycle — reducing efficiency, increasing wear, and degrading occupant comfort. This is a key finding requiring equipment right-sizing as an energy conservation measure.
Question 6: According to the ASHRAE Procedures for Commercial Building Energy Audits, which activity specifically distinguishes a Level II audit from a Level I audit?
- Reviewing 12 months of utility bills to establish an energy baseline
- Conducting a visual walk-through inspection of the building envelope and mechanical systems
- Performing detailed engineering calculations and energy modeling of major systems to quantify savings for each ECM (Correct answer)
- Interviewing building operators and occupants about comfort and operational issues
Correct answer: Performing detailed engineering calculations and energy modeling of major systems to quantify savings for each ECM
A Level I audit (Walk-Through Analysis) covers utility bill review, a brief site visit, and a list of low-cost/no-cost measures with rough estimates. A Level II audit (Energy Survey and Analysis) adds detailed engineering calculations, equipment measurements, and energy modeling for each energy conservation measure (ECM), producing capital cost estimates and projected savings with sufficient accuracy for investment decisions.
Certified Energy Auditor Certification Certified Energy Auditor Data Collection and Analysis 1
An energy auditor calculates an office building's Energy Use Intensity (EUI) as 95 kBtu/sq ft/year.
The national median EUI for office buildings is 69 kBtu/sq ft/year.
What does this comparison most accurately indicate?