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Clothes Washers Key Product Criteria
| Equipment | Criteria |
|---|---|
| Clothes Washers | Minimum Modified Energy Factor (MEF) of 1.72 and a maximum Water Factor (WF) of 8.0. |
The ENERGY STAR criteria for clothes washers changed on January 1, 2007. The new ENERGY STAR criteria require all qualified products to have a Modified Energy Factor (MEF) of 1.72 or greater as well as a Water Factor (WF) of 8.0 or lower. MEF is an equation for Energy Factor that takes into account the amount of dryer energy used to remove the remaining moisture content in washed items.
| Criteria/Product Type | Current Criteria Levels (as of January 1, 2007) |
July 1, 2009 | January 1, 2011 |
|---|---|---|---|
| ENERGY STAR top and front loading | MEF1 >= 1.72 WF2 <= 8.0 |
MEF >= 1.8 WF <= 7.5 |
MEF >= 2.0 WF <= 6.0 |
| Federal Standard top and front loading | MEF >= 1.26 | MEF >= 1.26 WF <= 9.5 |
|
1MEF = modified energy factor
2WF = water factor (gallons per cycle per cubic foot)
ENERGY STAR Qualified Clothes Washer Eligibility
Only front and top loader clothes washers with capacities of greater than 1.6 ft3 are eligible to earn the ENERGY STAR.
Energy Performance Metrics
Energy Factor (EF) is the previous energy performance metric for clothes washers. It is the quotient of the capacity of the clothes container, C, divided by the sum of the machine electrical energy for the mechanical action of a cycle, M, and the water heating energy required for a cycle, E. The equation is shown here:
| EF = | C |
| M + E |
The water heating energy may be from a gas or electric water heater. The units are cubic feet per kWh per cycle, ft3/kWh/cycle. The higher the value, the more efficient the clothes washer is.
Modified Energy Factor, MEF, is the energy performance metric for ENERGY STAR qualified clothes washers and all clothes washers as of January 1, 2004.
This metric has the same units as the energy factor (EF): ft3/kWh/cycle. 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:
| MEF = | C |
| M + E + D |
Water Factor, WF, is the present water performance metric 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 qualified clothes washers.
WF is the quotient of the total weighted per-cycle water consumption, 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 |
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 Energy Factor, Modified Energy Factor, or Water Factor may not appear on the EnergyGuide label.
