Commercial Variable Frequency Drive on Air Handling Unit Fan

Rebate amounts and program requirements are subject to change without notice. All homes or businesses are subject to inspection and usage data analyzed by participating in energy efficiency programs. Any rebates will be applied to past due amounts owed CPI before payment is issued.

A variable frequency drive (VFD) on an air handling unit (AHU) fan adds a VFD on a single-speed AHU. A typical building application for a VFD on an AHU fan is a multistory facility, such as a hospital, school or office building. These types of HVAC systems are typically located in the building’s mechanical room, and not on the roof.

With this technology, the VFD varies the speed of the fan to meet the conditions of the air handling system. As the fan motor slows down, it draws less power than at constant speed, resulting in energy savings.

Requirements and Specifications

  • This measure applies to retrofits only.


  • Project pre-approval from CPI.
  • Building heating fuel type may be either electric or gas;
  • VFD must be installed on existing AHU single-speed fan.


  • Retrofit adds a VFD to control the fan with variable-speed operation;
  • Any existing AHU throttling or bypass devices (e.g., inlet guide vanes, dampers, etc.) must be removed or permanently disabled.
  • The incentive form and all invoices must be completed and submitted to CPI.

Incentive Payment: $300 per horsepower