Department of Energy

U.S. Department of Energy Implements Criteria for ENERGY STAR® Water Heaters

April 1, 2008

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WASHINGTON, DC - The U.S. Department of Energy (DOE) today announced new ENERGY STAR® criteria for water heaters, the first in the history of the program.  According to DOE projections, by the end of the fifth year in effect, the new water heater criteria are expected to save Americans approximately $780 million in utility costs, avoid 4.2 million tons of carbon dioxide emissions, and achieve cumulative energy savings of more than 3.9 billion kilowatt-hours and 270 million therms of natural gas.  Water heating currently represents up to 17 percent of national residential energy consumption, making it the third largest energy user in homes, behind heating and cooling, and kitchen appliances.

"The ENERGY STAR® program empowers consumers to make smart energy choices that will save money, and energy, and reduce our carbon footprint," DOE Assistant Secretary for Energy Efficiency and Renewable Energy Andy Karsner said.  "Expansion of the ENERGY STAR® program to include water heaters will give Americans yet another way to more efficiently use energy in their homes and, in the interest of increasing energy security and addressing climate change, help further the President's goal of fundamentally changing the way this nation uses power."

For the first time, the following five categories of residential water heaters will be eligible for an ENERGY STAR® label: high-performance gas storage, whole-home gas tankless, advanced drop-in or integrated heat pump, solar, and gas condensing.

The new criteria for high-efficiency and high-performance gas storage water heaters will take effect in two phases.  The first phase goes into effect January 1, 2009, and requires gas storage water heaters to have a minimum Energy Factor (EF) of 0.62 - or they must be 6.9 percent more efficient than the Federal Standard.  Energy Factor is a measurement of relative energy efficiency for a water heater; the higher the Energy Factor, the more energy efficient the water heater.  A fifty-gallon high-performance gas storage water heater which meets the new ENERGY STAR® criteria, for example, is estimated to yield annual savings of 7.3 percent and save $26 using the national average gas rate.  Effective September 1, 2010, phase two requires the EF to increase to 0.67 - or 15.5 percent more efficient than the Federal Standard, resulting in annual savings of 14 percent and $51 for a single high-performance gas storage water heater.

Taking effect January 1, 2009, whole-home gas tankless water heaters which carry the ENERGY STAR® label must have a minimum EF of 0.82, minimum gallons-per-minute flow of 2.5 at a 77 degrees Fahrenheit rise, or be 41.4 percent more efficient than the current Federal standard.  A whole-home gas tankless water heater with a 0.82 EF is expected to achieve a 30 percent reduction in energy use and save a consumer approximately $108 in annual energy costs compared to a typical gas storage water heater.

ENERGY STAR® criteria for residential drop-in or integrated heat pump water heaters require a minimum EF of 2.0 or must be 121.2 percent more efficient than the Federal standard, and a minimum First-Hour Rating requirement of 50 gallons-per-hour, effective January 1, 2009.  Under these criteria, a heat pump water heater is expected to save consumers nearly 55 percent in energy use and yield annual energy savings of approximately $277 compared to a typical electric resistance water heater.

Effective January 1, 2009, solar water heaters must have at a minimum Solar Fraction of 0.50 and OG-300 certification from the Solar Rating and Certification Corporation (SRCC) in order to carry the ENERGY STAR® label.  The SRCC is a third-party organization that rates solar water heater systems.  By earning the OG-300 rating, solar water heaters have met certain performance, durability, reliability, and safety requirements set by the SRCC.  An OG-300 certified solar water heater with a 0.50 Solar Fraction and a fifty-gallon electric storage auxiliary water heater would achieve a Solar Energy Factor of 1.8, saving 50 percent in energy use and annual savings of $180, compared to a typical electric storage water heater.

To qualify for the ENERGY STAR® label, residential gas condensing water heaters must have an EF of 0.80, which is 37.9 percent more efficient than the Federal standard, and a minimum First-Hour Rating of 67 gallons-per-hour.  Under these criteria, taking effect January 1, 2009, a fifty-gallon water heater would save nearly 30 percent in energy consumption and result in $102 in annual energy savings compared to the conventional typical gas storage water heater.

ENERGY STAR® is a joint U.S. Department of Energy-U.S. Environmental Protection Agency (EPA) program, formed in 1992 as a voluntary, market-based partnership that seeks to reduce air pollution through increased energy efficiency.  DOE and EPA work to offer businesses and consumers energy-efficient solutions to save energy and money, while also helping to protect our environment.  More than 9,000 organizations have joined ENERGY STAR® as partners committed to improving the energy efficiency of products, homes and businesses.  The ENERGY STAR® label appears on more than 40 kinds of consumer products.  To learn more about ENERGY STAR®, and to view the revised program requirements, visit or call 1-888-STAR-YES.

Media contact(s):

Julie Ruggiero, (202) 586-4940