Energy
Motor Energy Savings Calculator
Compare existing and higher-efficiency motors to estimate annual energy and electricity cost savings.
Use the mechanical output required by the driven equipment.
Annual Energy Savings
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Estimated electricity reduction when delivering the same mechanical output with the higher-efficiency motor.
Existing electrical input
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New electrical input
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Power savings
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Input power reduction
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Existing annual energy use
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New annual energy use
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Annual energy savings
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Existing annual electricity cost
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New annual electricity cost
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Annual cost savings
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Method:
Electrical input power for each motor is calculated from:
Input Power =
Mechanical Output ÷ Motor Efficiency
Existing input power:
P₁ =
Pout ÷ η₁
New input power:
P₂ =
Pout ÷ η₂
Power savings are:
Power Savings =
P₁ − P₂
Annual energy savings are:
Energy Savings =
Power Savings × Operating Hours
Annual cost savings are:
Cost Savings =
Energy Savings × Electricity Tariff
The comparison assumes both motors deliver the same mechanical shaft output for the same operating hours.
Motor efficiency should represent efficiency at the actual operating load. Rated or nameplate efficiency may differ from real part-load efficiency.
This calculator estimates electricity savings only. A complete motor replacement assessment may also consider purchase and installation cost, maintenance, reliability, power factor, starting characteristics, service factor and remaining equipment life.