The U.S. Department of Energy recently modified the energy factor test procedure for clothes washers, changing the rating from a Modified Energy Factor (MEF) to an Integrated Modified Energy Factor (IMEF). This change in test procedure and rating label results in a difference between MEF and IMEF. Dave Roberts of NREL collected corresponding data for MEF and IMEF for a variety of clothes washers and determined there is a correlation between IMEF and MEF. This correlation is presented below. The regression equation can be used by Raters and by software providers to determine the correct entry for MEF in Eq 4.2-6. Correlation between IMEF and MEF for a Variety of Clothes Washers To clarify how clothes washers are treated in the ANSI/RESNET/ICC Standard 301 the RESNET Standards Development Committee (SDC) 300 has adopted the following formal interpretation on the efficiency of clothes washers: The value of MEF in Eq 4.2-6 shall be determined from new IMEF rating labels for clothes washers using the following equation: MEF = 0.503 + 0.95 * IMEF To view the formal SDC 300 interpretation go to RESNET Formal Interpretation on Clothes Washers Integrated Modified Energy Factor (IMEF)
