Motor Efficiency Calculator

Efficiency is useful output divided by input.

HVAC Pro calculator — inputs, formula and example are open to everyone.

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Formula

η = (hp × 0.7457) ÷ kW input × 100

Example calculation

10 hp output, 8.4 kW input → 88.8%.

Practical HVAC use

Compare motors and justify ECM upgrades.

Common mistakes

Using nameplate hp when the motor is lightly loaded.

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Educational tool. Results are estimates from the stated formulas; always confirm with manufacturer data and the code adopted in your jurisdiction. All calculators