The method
Before using the result
- Energy, peak demand and duration must describe the same boundary and period.
Worked examples
These original training examples illustrate the method for Certified Energy Manager (CEM). Use the matching “Load example” button above to explore a variation; example values are not equipment settings or prescribed criteria.
1. Worked example
Relate interval energy to peak demand over the same billing period. Reject inconsistent inputs that would make average demand exceed the recorded peak.
- Period energy
- 1,000 kWh
- Peak demand in same period
- 10 kW
- Period duration
- 200 h
- Average = 3600000000 / 720000 = 5000 W.
- Load factor = 5000 / 10000 × 100%.
- Average demand: 5,000 W
- Load factor: 50 %
2. Comparison example
Compare a different supplied condition using the same method. For Energy Cert Exam, the important check is that the input meaning, units and method assumptions still match the problem.
- Period energy
- 1,500 kWh
- Peak demand in same period
- 10 kW
- Period duration
- 200 h
- Average = 5400000000 / 720000 = 7500 W.
- Load factor = 7500 / 10000 × 100%.
- Average demand: 7,500 W
- Load factor: 75 %
Check your understanding
1. Which relationship is used?
Average demand = energy/time; load factor = average demand/peak demand.
2. Which assumption should you check first?
Energy, peak demand and duration must describe the same boundary and period.
3. How should you verify a different unit system?
Convert every input to the displayed calculation units first. Equivalent physical inputs must give equivalent results; a unit label alone does not convert a number.
Continue with the matching exam topic
This tool connects to Certified Energy Manager (CEM) free practice. Work through a question independently, then use the calculation steps to identify where your method differs. The tool stays free whether or not you choose paid preparation.