VFD Energy Savings Calculator

Motor & Operating Parameters

Motor HP

Motor Efficiency (%)

VFD Efficiency (%)

Electricity Rate ($/kWh)

Annual Operating Hours

VFD / Drive Installed Cost ($)

Operating Speed

80%

40%60%80%100%

Energy Savings Results

Full-Speed kW Input

—

Reduced-Speed kW

—

Annual kWh Saved

—

kWh/yr

Annual $ Saved

—

$/yr

Simple Payback

—

years

CO₂ Avoided

—

lbs/yr

Speed vs. Power (Affinity Law Cube Relationship)

Speed	% of Full Power	kW at Speed	kWh/yr	$/yr

Power scales with the cube of speed (P ∝ N³). At 80% speed: power = 51% of full; at 60% speed: power = 22% of full. Actual savings depend on system curve, VFD efficiency, and motor loading at reduced speed.

Do the full calculation in AIM Works

This calculator handles one step. AIM Works runs the complete MEP design workflow — thermal load calculations, duct & pipe networks, equipment selection, code compliance, and an AI design assistant — in one tool.

✓ ASHRAE 62.1 ventilation + CLTD/CLF/RTS load methods

✓ Darcy-Weisbach pipe & duct network solvers

✓ ASHRAE 90.1 / IMC / NFPA compliance checks

✓ 20 free AI design messages included in trial