VFD Pump Energy Savings Calculator

Estimate annual energy savings from adding a variable frequency drive to a constant-speed pump, or from optimizing differential pressure setpoint on an existing VFD system. Enter pump curve data (flow, head, and efficiency at multiple operating points), system head curve, and building load profile to compare scenarios over an 8,760-hour simulation.

For each hour, the calculator finds the operating point at the intersection of the pump curve and system curve, then calculates kW directly from flow, head, pump efficiency, motor efficiency, and VFD efficiency — using the actual pump curve data, not simplified estimates. Supports both constant and linear reset DP setpoint strategies so you can model the savings from lowering setpoint at part load. Load profiles are driven by TMY3 weather data with automatic pump staging logic.

Reports include annual kWh savings, monthly comparisons, and operating cost savings for use in energy audits and ESCO proposals.