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Fan Power ConfiguratorPower • Efficiency • Energy • Cost • Savings

Fan Power Configurator

Free online fan power calculator for HVAC and industrial fan systems, built around the ANSI/AMCA 207 power-flow model that breaks electrical input down into fan, drive, motor and VFD stages instead of a single black-box number. Compare VFD, damper, inlet guide vane and on/off flow-control strategies side by side, size the motor against a standard IEC catalogue with an automatic loading verdict, and look up nominal motor efficiency straight from the IEC 60034-30-1 IE-class tables. Model your actual annual duty profile, compare two fan options on payback and 10-year life-cycle cost, and estimate CO2 impact from real grid carbon-intensity data by country — free, with instant XLS/PDF export, no sign-up required.

1

Inputs

Duty point
Efficiencies
Electricity & operating time
2

Power flow

From air to grid — where power goes.

Specific Fan Power (SFP) i
SFP1 (best)SFP2SFP3SFP4SFP5+ (worst)
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3

Operating profile & energy

Define how the fan actually operates during the year — speed steps use fan-affinity scaling (Q∝n, Δp∝n², P∝n³) from the 100% duty point above.

Power vs speed

4

Control method comparison

Illustrative, typical centrifugal-fan control-method curves — not measured, not your specific fan. Consult manufacturer performance curves for real savings.

Electrical power vs airflow

5

Motor sizing

Based on required motor shaft power (after drive losses, before motor/VFD losses).

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Motor loading—
6

System curve & operating point

Δpsystem = Δpstatic + k·Q², k solved from your duty point. Shows why P∝n³ (used in Profile & Control Method) is only exact with no fixed/static component.

7

Compare fans

Same duty point, two efficiency options — reference vs. a more efficient alternative.

8

10-year cost analysis

Cumulative energy cost, including the annual price increase set in Inputs.

9

Environmental impact

Based on Fan B's (efficient option's) energy consumption and the emission factor set in Inputs.

SFP (Specific Fan Power)

The lower the SFP, the more efficient the fan system.

Fan laws

Q∝n, Δp∝n², P∝n³ — reducing speed has a cubic impact on power.

Standards

Power-flow breakdown follows the AMCA 207 fan/transmission/motor/controller system model.

Important

Results are estimates from typical/illustrative relationships. Use manufacturer performance data for final selection.

How this calculator works

The power-flow breakdown follows the same system decomposition as ANSI/AMCA 207, "Fan System Efficiency and Fan System Input Power Calculation" — air power is divided by fan efficiency to get shaft power, then by drive (belt/coupling) efficiency for motor output power, then by motor efficiency for motor input power, then by VFD/controller efficiency for the power actually drawn from the grid.

Air power (W) = Q (m³/s) × Δp (Pa) Shaft power = Air power / ηfan Motor output = Shaft power / ηdrive Motor input = Motor output / ηmotor Grid power = Motor input / ηVFD ηoverall = Air power / Grid power

The duty/load profile uses the fan affinity laws (Q∝n, Δp∝n², P∝n³) to scale power at each speed step from the 100% duty point, then sums hours × power for annual energy — a much more realistic annual-energy estimate than assuming the fan runs at a single constant point all year.

The control-method comparison (VFD vs. damper vs. inlet guide vane vs. on/off) uses simple, clearly-labelled typical relationships between airflow and power for each method, not a measured fan curve — actual savings depend heavily on the specific fan, system curve and control quality. On/off cycling's linear average-power model also ignores cycling wear and control-quality downsides that a continuously-modulated method doesn't have.

All results are engineering estimates from the inputs and the typical/illustrative relationships described above — not a substitute for manufacturer fan curves, motor datasheets or a full system design. Standard motor sizes are a generic IEC reference list; always verify against the manufacturer's actual catalogue.