Water Heater Energy Factor Calculator

The energy factor ef indicates a water heater s overall energy efficiency based on the amount of hot water produced per unit of fuel consumed over a typical day.

Water heater energy factor calculator. Hi larry the energy that is used to heat water from 40 degrees to 60 is the same amount that is lost when the water cools down from 60 to 40 only changed sign. An energy factor is a metric used in the united states to compare the energy conversion efficiency of residential appliances and equipment. Electric water heaters typically have energy factors between 0 75 and 0 95. Typical fifty gallon electric resistance storage water heaters have energy factors that range from 0 904 to 0 95.

The energy factor is currently used for rating the efficiency of water heaters dishwashers clothes washers and clothes dryers. The water heaters themselves haven t changed but the way we calculate the ratings and other facts and figures associated with them is different. The energy factor is based on the amount of hot water produced per unit of fuel consumed per day. Use the energy factor to determine the energy efficiency of a storage tankless or demand type water heater or heat pump water heater.

Next you can adjust your current water heater s energy factor as well as the energy factor of your new water heater. The term is used by the united states department of energy to develop and enforce minimum energy conservation standards under. Using the doe test procedure for calculations a fifty gallon electric resistance storage water heater with an energy factor of 0 95 would consume 4 622 kilowatt hours per year see table 1 on page nine for figures. Antonio january 5 2019.

Expressed as a decimal the uniform energy factor is determined by running a department of energy specified simulated use test sut. Quantity of water heaters to be purchased unit s 1 unit see assumptions for various daily water use totals. To calculate a water heater s energy factor you take the amount of energy the water heater puts to use and divide it by the total amount of energy that goes into powering the unit. Energy factor 0 92 electric 0 61 gas energy cost 0 06 per kwh 60 per therm.

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. The higher the energy factor of a water heater the more efficient it is. The comparison assumes a storage tank water heater as the input type. At the bottom of the calculator are more settings you can adjust for further accuracy such as the cold water intake temperature the water heater temperature and the cost of electricity.

A water heater s energy factor ef is a measure of useful energy coming out of the water heater divided by the amount of energy going in.