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Clothes Washers Key Product Criteria

The ENERGY STAR criteria for clothes washers was changed on March 7, 2015 and is as follows:

Product Type Current Criteria Levels (as of March 7, 2015)
ENERGY STAR Residential Clothes Washers, Front-loading (> 2.5 cu-ft) IMEF ≥ 2.38
IWF ≤ 3.7
ENERGY STAR Residential Clothes Washers, Top-loading (> 2.5 cu-ft) IMEF ≥ 2.06
IWF ≤ 4.3
ENERGY STAR Residential Clothes Washers (≤ 2.5 cu-ft) IMEF ≥ 2.07
IWF ≤ 4.2
ENERGY STAR Commercial Clothes Washers MEF ≥ 2.2
WF ≤ 4.5

ENERGY STAR Qualified Clothes Washer Eligibility

Only front and top-loading clothes washers with capacities greater than 1.6 ft3 and less than 6.0 ft3; and are not defined as Combination All-In One Washer-Dryers or Residential Clothes Washers with an Optional Dry Cycle are eligible for ENERGY STAR Certification.

Energy Performance Metrics

Modified Energy Factor, MEF, is the energy performance metric for ENERGY STAR certified commercial clothes washers as of March 7, 2015.

MEF is the quotient of the capacity of the clothes container, C, divided by the total clothes washer energy consumption per cycle, with such energy consumption expressed as the sum of the machine electrical energy consumption, M, the hot water energy consumption, E, and the energy required for removal of the remaining moisture in the wash load, D. The higher the value, the more efficient the clothes washer is. The equation is shown below and the metric units are ft3/kWh/cycle:

MEF =     C    
M + E + D

Integrated Modified Energy Factor, IMEF, is the energy performance metric for ENERGY STAR certified residential clothes washers as of March 7, 2015.

IMEF is the quotient of the capacity of the clothes container, C, divided by the total clothes washer energy consumption per cycle, with such energy consumption expressed as the sum of the machine electrical energy consumption, M, the hot water energy consumption, E, the energy required for removal of the remaining moisture in the wash load, D and the combined low-power mode energy consumption, L. The higher the value, the more efficient the clothes washer is. The equation is shown below and the metric units are ft3/kWh/cycle:

IMEF =       C      
M + E + D + L

Water Factor, WF, is the water performance metric for commercial clothes washers that allows the comparison of clothes washer water consumption independent of clothes washer capacity. Manufacturers must submit their water consumption factors with their ENERGY STAR certified commercial clothes washers.

WF is the quotient of the total weighted per-cycle water consumption for cold wash, Q, divided by the capacity of the clothes washer, C. The lower the value, the more water efficient the clothes washer is. The equation is shown below:

WF =  Q
C

Integrated Water Factor, IWF, is the water performance metric for residential clothes washers that allows the comparison of clothes washer water consumption independent of clothes washer capacity. Manufacturers must submit their water consumption factors with their ENERGY STAR certified residential clothes washers.

IWF is the quotient of the total weighted per-cycle water consumption for all wash cycles, QA, divided by the capacity of the clothes washer, C. The lower the value, the more water efficient the clothes washer is. The equation is shown below:

IWF =  QA
C

The federal EnergyGuide label on clothes washers shows annual energy consumption and cost. These figures use the energy factor, average cycles per year, and the average cost of energy to make the energy and cost estimates. The Modified Energy Factor, Integrated Modified Energy Factor, Water Factor, or Integrated Water Factor may not appear on the EnergyGuide label.