Motor Fan Energy Savings Calculator

Calculate fan savings

Fan energy methodology

Fan savings can come from more than one source. A lower operating speed changes the modeled load power, while a changed schedule reduces the number of hours of operation. Efficiency changes then influence how much electrical input is required for the resulting fan load.

The generalized speed component is:

Speed-adjusted load power = Baseline power × speed ratioⁿ

The proposed electrical power is then adjusted from the entered baseline efficiency to the proposed efficiency.

Use a defensible power-speed relationship

The exponent should represent the fan/application behavior being studied. The tool intentionally asks for it instead of presenting one universal value as a guaranteed law for every installation.

Schedule savings are different

A fan that operates six thousand hours instead of seven thousand hours saves energy because it runs less, even before speed changes are considered. Keeping speed and schedule variables separate makes that distinction visible.

Limits and engineering checks

• The proposed fan condition must still provide the required airflow and pressure.
• Real fan systems may have control, damper, duct and system-curve effects not represented here.
• Efficiency inputs should come from credible equipment or measurement data.
• The calculator does not determine whether a speed or airflow is safe for the equipment.

FAQs

Can speed remain at 100%?

Yes. The calculator can then isolate schedule and efficiency changes.

Why are baseline and proposed hours separate?

They allow the calculation to capture scheduling improvements independently from speed changes.

Can proposed efficiency be lower?

Yes. The model accepts any valid value so you can analyze a trade-off rather than assuming efficiency must improve.

Is the speed exponent the same as fan efficiency?

No. The exponent describes a power-speed relationship; efficiency describes conversion or system losses.

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