Facility Cert Exam · Free practical tool

Pump and fan operating cost comparison

Compare measured electrical inputs for a building-services upgrade. Document whether both operating points deliver equivalent service before interpreting the estimated annual difference.

Free results and workingNo signupLocal calculations
Your inputsCalculated on your device

Example values loaded. Replace them with your own measurements.

Your result
↗

Make the numbers make sense.

Enter your values, choose the units, and calculate. You’ll see the result and the working here.

Free results. No account needed.

The method

Energy before = Pbaseline × baseline time; energy after = Pproposed × proposed time; savings = energy before − energy after. Cost difference = kWh difference × tariff.

Before using the result

  • Tariffs, operating hours and costs are user assumptions. Results exclude financing, taxes, demand charges and changes in equipment performance.
  • Baseline and proposed systems provide comparable service. This is an input comparison, not verified savings.

Worked examples

These original training examples illustrate the method for BOMI Systems Maintenance Administrator (SMA). Use the matching “Load example” button above to explore a variation; example values are not equipment settings or prescribed criteria.

1. Worked example

Compare measured electrical inputs for a building-services upgrade. Document whether both operating points deliver equivalent service before interpreting the estimated annual difference.

Baseline input power
10 kW
Proposed input power
7 kW
Annual operating time
2,000 h
Operating schedules
Same hours
Energy tariff (currency units/kWh)
0.15
  1. Power difference = 3000 W.
  2. Baseline = 10000 × 7200000 = 72000000000 J; proposed = 7000 × 7200000 = 50400000000 J.
  3. Energy difference = 72000000000 − 50400000000 = 6000 kWh.
  4. Cost difference = 6000 × 0.15.
  • Baseline annual energy: 72,000,000,000 J
  • Proposed annual energy: 50,400,000,000 J
  • Annual energy difference: 21,600,000,000 J
  • Annual cost difference: 900 currency units

2. Comparison example

Compare a different supplied condition using the same method. For Facility Cert Exam, the important check is that the input meaning, units and method assumptions still match the problem.

Baseline input power
10 kW
Proposed input power
6 kW
Annual operating time
2,000 h
Operating schedules
Same hours
Energy tariff (currency units/kWh)
0.15
  1. Power difference = 4000 W.
  2. Baseline = 10000 × 7200000 = 72000000000 J; proposed = 6000 × 7200000 = 43200000000 J.
  3. Energy difference = 72000000000 − 43200000000 = 8000 kWh.
  4. Cost difference = 8000 × 0.15.
  • Baseline annual energy: 72,000,000,000 J
  • Proposed annual energy: 43,200,000,000 J
  • Annual energy difference: 28,800,000,000 J
  • Annual cost difference: 1,200 currency units

Check your understanding

1. Which relationship is used?

Energy before = Pbaseline × baseline time; energy after = Pproposed × proposed time; savings = energy before − energy after. Cost difference = kWh difference × tariff.

2. Which assumption should you check first?

Tariffs, operating hours and costs are user assumptions. Results exclude financing, taxes, demand charges and changes in equipment performance.

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 BOMI Systems Maintenance Administrator (SMA) 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.

Tool terms and notices