New residential water heater energy efficiency standards are coming quickly for the manufacturers, distributors, wholesalers and contractors that produce and install these appliances. In less than one year, the new minimum energy efficiency standards will be in effect for water heaters manufactured after April 15, 2015.

The 2010 Department of Energy Final Rule on energy efficiency mandates a higher Energy Factor (EF) rating on virtually all residential water heating products, including gas, electric, oil and tankless gas water heaters.  

According to The Energy Efficiency Standards group, the efficiency metric for residential water heaters is the Energy Factor (EF), which 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.

The EF accounts for recovery efficiency — how efficiently the heat from the energy source is transferred to the water; standby losses — the percentage of heat loss per hour from the stored water compared to the heat content of the water (for water heaters with storage tanks); and cycling losses — the loss of heat as the water circulates through a water heater tank, and/or inlet and outlet pipes.

According to Karen Meyers, corporate director of government relations at Rheem, the DOE is required to review efficiency standards to determine if the higher efficiency rate can generate enough energy savings.

“There are all types of things DOE has to do to make sure a new minimum efficiency level can be justified,” says Meyers. “Typically rule making takes about two years, and Rheem has been very involved with this process from the very beginning.”

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According to Harvey Sachs, Ph.D, senior fellow, at the American Council for an Energy Efficient Economy, the 55-gallon mark will be a transition point.

“The DOE decided to separate out larger water heaters used presumably by people who have larger water use,” says Sachs. “When you look at larger water users it becomes cost effective to require heat pump water heaters for electric service and condensing tank technology for gas service (condensing is not required for gas tankless), and that is what DOE has done.”