For gas condensing water heaters the energy factor must be 0 8 or higher to qualify for the energy star label.
Water heater energy factor list.
Define consistent standards for measuring energy efficiency performance.
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.
Electric water heaters typically have energy factors between 0 75 and 0 95.
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.
365 days year x 12 03 kwh day ef x fuel cost kwh annual cost of operation.
It s important to note that energy factors can vary significantly depending on their fuel source.
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.
The uniform energy factor.
Expressed as a decimal the uniform energy factor is determined by running a department of energy specified simulated use test sut.
As of september 1 2010 a water heater needs to have an energy factor of 0 67 or higher in order to qualify for the energy star label.
365 x 12 03 2 0 x 0 0842 185.
A heat pump water heater with an ef of 2 0 and an electricity cost of 0 0842 kwh.
Simplify the water heater selection.
You need to know or convert the unit cost of electricity by kilowatt hour kwh.
The new uef rating method improves the industry s ability to.