This program calculates the potential energy savings that may be realized using variable frequency drives (VFDs) to power pumps and fans. It allows users to compare the costs of conventional methods, such as valves for pump control and dampers for fan control, to those of VFDs. Energy use can be calculated based on built-in sample data, or by entering the minimum pump or flow percentages, annual operating hours, cost per kilowatt, and other site-specific information. The tool is available as an online calculator or a mobile application for an iPad, iPhone, Blackberry, or Android system.