A Variable Frequency Drive (VFD) Hvac is a power control device that regulates the voltage and frequency of an electric motor, allowing it to operate at various speeds for greater energy efficiency. It can be set up to accelerate or decelerate the motor at different rates depending on the required amount of cooling or heating output from the motor. This technology can reduce electricity usage by 30 – 60% in motor-driven applications in commercial, industrial, agriculture and residential settings.