Compare measured fan airflow, pressure, and speed with scheduled values and an affinity-law speed prediction.
Why it matters: A single percent-of-design value can hide whether speed, system resistance, or the measurement basis explains a performance difference.
ΣCALCULATE · VERIFY · INTERPRET
Calculated result
Engineering evaluation
Within entered screening criteria
Measured flow relative to schedule (PF)95 %
Measured pressure relative to schedule (PP)
88 %
Measured speed relative to schedule (PN)
95 %
Affinity-predicted flow at measured speed (Qe)
9,500 cfm
Measured deviation from speed prediction (informational) (δQ)
0 %
Engineering interpretation
Measured fan flow is 95% of schedule. At 95% of scheduled speed, the first-power affinity estimate is 9500 cfm; the measured flow differs from that estimate by 0%. The affinity comparison is informational and does not determine the status color. Review the current manufacturer curve, system configuration, test method, and measurement uncertainty before disposition.
Motor-driven equipment
Estimate electrical demand and energy use
Use nameplate information and an operating schedule to screen motor input power, current, annual energy, and operating cost. Results update automatically.
Optional companion calculation
Choose the motor nameplate output-power convention.
Rated shaft output, not electrical input.
Used to estimate current; it does not change the hp-based energy result.
Use efficiency at the evaluated load point when available.
Use measured or defensible operating load rather than motor nameplate size alone.
Used only for the estimated current calculation.
Assumes all selected motors operate concurrently at the entered load.
Replace the profile with the actual occupied, process, or control schedule.
$/kWh
Use the applicable marginal utility energy charge; demand charges are not included.
Estimated result
Total motor input power (Pin,total)6.21 kW
Current per motor (I)
9.18 A
Total coincident current (Itotal)
9.18 A
Daily energy (Ed)
50 kWh/day
Annual operating hours (Hy)
2,080 h/year
Annual energy (Ey)
12,925 kWh/year
Annual energy cost (Cy)
$1,551/year
Equations and assumptions
Nameplate-based screening method
Horsepower is converted using 1 hp = 0.7457 kW. This estimate assumes steady average load and the entered operating-point efficiency. Voltage and power factor affect estimated current, but hp, load, efficiency, quantity, and schedule establish the energy estimate. VFD speed profiles, cycling, standby power, demand charges, and process variation require separate evaluation.
These engineering tools are provided for educational, preliminary evaluation, field verification, and commissioning support. Results depend on the accuracy of user-entered information and the assumptions stated for each calculation. Every colored status and comparison is a screening indicator only; project criteria, contract requirements, applicable codes, manufacturer instructions, measurement uncertainty, and authorized engineering judgment govern. The tools do not replace project-specific engineering analysis or the judgment of a licensed professional engineer.
