The Northwest Energy Efficiency Alliance (NEEA) contracted with Underwriters Laboratory (UL) to measure the energy use of matched pairs of washers and dryers and Kannah Consulting to analyze the collected data and develop recommendations. This new analysis builds off previous alliance research, including “Coming Clean: Revealing Real-World Efficiency of Clothes Washers,” and the 2016-2017 Residential Building Stock Assessment. Seven washer and dryer pairs were selected for the study to determine how accurately the U.S. Department of Energy’s (U.S. DOE) rated energy use differs from the energy use when tested in more realistic conditions. The pairings were run through a battery of tests comparing energy use, efficiency and cycle time.
The analysis revealed that the manufacturer-reported U.S. DOE ratings generally underestimate the energy use of the washer and dryer pairs when tested under more realistic conditions and that the pairings use significantly more electricity and natural gas than estimated. In addition, the current U.S. DOE test procedures for dryers greatly underestimate the energy consumption under realistic conditions. Finally, there are significant cycle and energy-use differences between washer and dryer technologies, suggesting an opportunity for an ENERGY STAR® matched pair specification to support the most efficient matched washer-dryer sets.