Variable speed drives enable motors to run at variable speeds. Applied to fans and pumps, variable speed motors can be used to control flow rates without the use of mechanical means such as valves, dampers, and guide vanes. Energy savings are achieved by limiting flow to needed levels, and achieving flow rates more efficiently than a pump or fan operating at full speed with mechanical flow control.
This measure applies to pumps and fans with motors up to 100 HP where variable speed control is not required by code for the project. There are measure applications for both retrofits and new projects. A retrofit is defined as a project in which the existing fan or pump is not replaced. A drive can be installed on an existing motor or the motor can be replaced as part of the project, and the drive may be integrated with the motor. A new project is defined as a project where the fan or pump itself is new.
Savings for fans are based on empirical load factors (average power draw with and without a VSD) from BPA's Adjustable Speed Drive Market Model. Savings for pumps are based on NEEA research: metered pump data and simulation of counterfactual systems (e.g., pump without drive where the existing pump has a drive). This measure is categorized as “Planning” to reflect significant uncertainties in the savings estimates and the need for research on current practice VSD saturation, annual hours of use (particularly for agricultural applications), and the pre/post load profiles for the range of measure applications.
The Potato/Onion Shed Variable Frequency Drive measure was combined into this one in October 2026.
