Microwave Ovens

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THE PRODUCT:

Microwave ovens cook or heat food and beverages by converting electricity to microwave radiation to heat water molecules within the substance.

POTENTIAL STANDARD:

No standards for microwave ovens currently exist. In a rulemaking concluded in 2009, DOE initially proposed a standard for microwave ovens that would limit standby power consumption to 1 W. However, in the final rule, DOE decided to defer setting a standard to allow for revisions to the test procedure. DOE published an interim final rule for test procedures for standby and off mode in March 2011 (there is currently no test procedure for active mode). A supplemental notice of proposed rulemaking (SNOPR) to determine standards for standby and off mode was published February 14, 2012. This SNOPR proposed two product categories. DOE determined that a maximum standby power of 1.0 watt was appropriate for microwave-only ovens and countertop combination microwave ovens and a maximum 2.2 watts for built-in and over-the-range combination microwave ovens; DOE did not set an off mode power standard. According to DOE, a federal standard at these levels is estimated to save 0.41 quads of primary energy over the 30 year analysis timeframe. This standard would also generate between $1.5-3.5 billion in net present value savings.

KEY FACTS:

According to the recently released Residential Energy Consumption Survey (RECS) by the EIA, about 88% of U.S. households own a microwave. A maximum standby power level of 1 watt for microwave-only ovens and countertop combination ovens would decrease standby mode consumption by about 75%. The standby power level of 2.2 watts for the second product class would mean a decrease of over 50%. DOE identified four technology options that could reduce electricity consumption in standby mode: 1) lower-power display options; 2) cooking sensors with no standby power requirement; 3) improved power supply and control board options; and, 4) automatic power-down. Low-power display technologies like liquid crystal display (LCD) or light-emitting diode (LED) displays alone can achieve close to 1 W savings. Adding an automatic power-down element, which turns off most power-consuming components after a certain period of inactivity, could achieve standby power levels of less than 1 W.