Water Heater Energy Factor List

Expressed as a decimal the uniform energy factor is determined by running a department of energy specified simulated use test sut.

Water heater energy factor list.

The uniform energy factor for residential and certain commercial water heaters refers to its efficiency when run under standardized conditions for a 24 hour period. Beginning june 12 2017 ef ratings will be replaced with the new industry standard for measuring energy efficiency in water heaters called uniform energy factor uef. This means that between 75 and 95 percent of the energy used to heat the water ends up being delivered to your taps as usable hot water. For gas condensing water heaters the energy factor must be 0 8 or higher to qualify for the energy star label.

The new uef rating method improves the industry s ability to. Define consistent standards for measuring energy efficiency performance. You need to know or convert the unit cost of electricity by kilowatt hour kwh. A heat pump water heater with an ef of 2 0 and an electricity cost of 0 0842 kwh.

It s important to note that energy factors can vary significantly depending on their fuel source. The uniform energy factor. 365 x 12 03 2 0 x 0 0842 185. Simplify the water heater selection.

365 days year x 12 03 kwh day ef x fuel cost kwh annual cost of operation. The higher the ef value is the more efficient the water heater. Ef is determined by the department of energy s test method outlined in the 10 cfr parts 200 to 499 edition revised as of january 1 2014. An older measure of water heater overall efficiency that is being phased out due to new test methods for water heaters.