Energy Factor (EF)
Energy Factor(EF) is an overall efficiency rating of the water heater. The higher the EF, the more efficient the model. Water heaters with high EF ratings may cost more initially, but save energy and money in the long run. Eventually, they will pay for themselves through a lifetime of energy savings.
Water heaters listed in the energy factor ratings include:
- Electric storage water heaters with energy input ratings of 12kWh or less and with a storage capacity of not less than 20 gallons nor more than 120 gallons.
- Gas storage water heaters with energy input ratings of 75,000 BTU/Hr. or less and with a storage capacity of not less than 20 gallons nor more than 100 gallons.
- Gas instantaneous water heaters with input ratings greater than 50,000 BTU/Hr. but less than 200,000 BTU/Hr
First Hour Rating
Another important factor is choosing a water heater, the 1st Hour Rating is an indicator of how much hot water a particular model can provide. The rating, in gallons of usable(desired temperature) hot water is reached by combining the amount of usable hot water stored in the tank, plus how many gallons of usable hot water the water heater can generate in one hour of operation. For example, if a 40 gallon natural gas water heater will store 31 gallons of usable hot water and can deliver 41 gallons of usable hot water in the first hour its 1st Hour Rating is 72 gallons. 1st Hour Ratings are included in Energy Factor Charts.
Natural Average Energy Cost:
*$0.1065 Cost per kWh (Electric)
*$1.2180 Cost per Therm. (Nat. Gas)
*$1.8700 Cost per Gal. (Propane Gas)
- Information supplied by the Gas Appliance Manufacturers' Association and Bradford White.
- The Energy Factor Chart is subject to change without notice in accordance with our policy of continuous improvement.