How do I calculate Motor Energy Savings — IE Class Comparison?

To calculate Motor Energy Savings — IE Class Comparison: Enter Shaft power, Current efficiency (old motor), New motor efficiency and other values. Click Calculate. INDUGRID computes the result instantly using the formula: Savings [kWh/yr] = P_shaft × (1/η_old − 1/η_new) × hours | Payback = Investment / (Savings × €/kWh). No registration required.

What units does the Motor Energy Savings — IE Class Comparison calculator use?

The Motor Energy Savings — IE Class Comparison calculator uses the following units: kW, %, h/year, €/kWh, €. SI units are used by default.

Energy & Sustainability

Motor Energy Savings — IE Class Comparison

Calculate annual energy cost savings and payback period when upgrading from a lower IE class motor to a higher efficiency IE class.

Units:

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💡The EU Ecodesign Regulation (2019/1781) requires IE3 for motors 0.75–1000 kW since July 2021, and IE4 for 75–200 kW since July 2023. Replacing an IE1 motor with IE3 typically saves 2–5% energy — which at 8000 hours/year pays back in 1–3 years.

Savings [kWh/yr] = P_shaft × (1/η_old − 1/η_new) × hours | Payback = Investment / (Savings × €/kWh)

Input

Shaft power iNominal shaft power (mechanical output) of the motor in kW.

Current efficiency (old motor) iEfficiency of the existing motor in %. IE1: 82–92%, IE2: 84–93%, IE3: 87–95%.

New motor efficiency iEfficiency of the new motor in %. IE3 15kW: 92.1%, IE4 15kW: ~93.5%.

Operating hours per year iAnnual operating hours at full load.

h/year

Energy price iIndustrial electricity tariff in €/kWh. EU industrial average: €0.12–0.20/kWh.

€/kWh

Cost of new motor iPurchase and installation cost of the replacement motor in €.

€

Result

Electrical input power (old) [kW] —

Electrical input power (new) [kW] —

Power saving [kW] —

Annual energy saving [kWh/year] —

Annual cost saving [€/year] —

Simple payback period [months] —

CO₂ reduction [kg CO₂/year] —