VFD Energy Cost Savings Calculator
Annual dollar savings from adding a VFD to a fan.
Enter your values
ⓘ Live results
Results
- Annual energy saved
- 52,031 kWh
- Annual cost savings
- $6764
- New average power
- 6.33 kW
- Percent power saved
- 57.8%
Quick answer
Annual savings equal the power reduction at reduced speed times annual run hours times the electricity rate.
Savings = (P1 - P1 x (N2/N1)^3) x hours x rate
How to use the VFD Energy Cost Savings Calculator
- 1Enter the fan's full-speed power draw and the average speed it will run at with a VFD.
- 2Enter annual operating hours and your electricity rate.
- 3Read the annual energy and cost savings to help justify the VFD payback.
Worked example
Using the values the calculator loads with:
Inputs
- Full-speed power15 kW
- Average VFD speed75 % of full speed
- Annual run hours6000 hr
- Electricity rate0.13 $/kWh
Results
- Annual energy saved52,031 kWh
- Annual cost savings$6764
- New average power6.33 kW
- Percent power saved57.8%
Frequently asked questions
How do I find average VFD speed?
Use trend logs from an existing BAS, or estimate from typical load profiles for the application.
Does this include drive losses?
No — VFD and motor conversion losses are small (a few percent) and can be added as a simple derate if needed.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.