A measure of how efficiently a device uses power. Power factor may range from 0 to 1, with 1 being the ideal. A device that converts all the power supplied to it by the power utility into watts is said to have a power factor of 1. Devices with PF greater than or equal to 0.90 are referred to as High Power Factor (HPF) devices, whereas devices with PF less than 0.60 are referred to as low power factor devices.