A measure of the overall efficiency of a water heater, based on its recovery efficiency, standby loss and energy input as set out in standardized Department of Energy test procedures.
Overall efficiency of a water heater or other appliance. The amount of hot water produced per unit of gas or electricity purchased. The higher the energy factor number, the more efficient the water heater.
The energy factor is the measure of the overall efficiency of a water heater based on the model’s recovery efficiency, standby losses, and energy input. It is determined by U.S. Department of Energy test procedures and can be used in conjunction with local fuel costs to estimate the annual cost of operation.