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VFD Energy Savings Calculator

Variable Frequency Drive ROI for pumps/fans

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VFD (Variable Frequency Drive) Energy Savings

Calculate energy savings from installing VFD on pumps, fans, conveyors. Affinity laws (cubic for centrifugal) drive massive savings on partial-load operation.

How to use this tool

  1. 1

    Application type

    Pump, fan, conveyor, compressor.

  2. 2

    Load profile

    % time at each speed.

  3. 3

    See savings

    Cubic law for centrifugal loads.

Frequently Asked Questions

Why cubic law?
Centrifugal pumps + fans: power ∝ speed³. 80% speed → 51% power. 50% speed → 12.5% power. Massive savings on partial-load operation. Constant-torque loads (conveyor): linear, less savings.
Throttle valve vs VFD?
Throttling pumps wastes 30-60% of energy as heat/friction. VFD slows pump itself = no waste. ROI typically 6-24 months for HVAC pumps.
When NOT to use VFD?
Constant-load applications (conveyor at fixed speed): savings minimal. Very small motors (<1 kW): VFD cost > savings. High harmonic-sensitive grids: need filtering.

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