A high efficiency washing machine is one that washes clothes using significantly reduced levels of water and energy. Most high efficiency washing machines utilize a tumbling action instead of the agitation motion traditionally used.
The majority of high efficiency washers are front loading. Their doors open to the front like a traditional dryer rather than on top. Their drums rotate on a horizontal axis spinning during the washing cycle with the clothes tumbling within.
About 40% less water is used in a high efficiency washing cycle as clothes do not soak or sit in a tub of water. The level of water in the drum remains below the plane of the door. A low level of water is introduced during the beginning of a wash cycle and as the clothes absorb that water, more is added until clothes are saturated and the specified low level of water in the drum is detected by the machine.
A traditional washer will use 40 to 47 gallons (151 to 178 liters) of water per cycle. High efficiency washers use 11 to 32 gallons (42 to 121 liters) of water per cycle. Energy savings with high efficiency washers are estimated at 50% to 60% each load. Much of the energy savings afforded by high efficiency washing machines are a result of the significant reduction in hot water they require.
The horizontal drums utilized in a high efficiency washer spin at a much faster rate than other machines. This allows more water to be extracted from the clothes during the spin cycle. Consequently, clothes contain less moisture at the end of the wash and require less time and energy to dry.
A high efficiency washer will use two to four clean rinses per cycle, reducing levels of detergent residue left on clothing as well as improving cleaning efficiency by not having clothes sitting in dirty water.
The tumbling motion causes clothes to circulate freely in a high efficiency washing machine resulting in a more effective cleaning process as well as less wear and tear on garments. The tumble motion is gentler with less stress and pulling on fabric than the agitation motion. Tumbling and increased circulation of items in the drum requires that a high efficiency detergent be used in these machines. High efficiency detergents have fewer suds, requiring less water to them rinse away.
The U.S. Department of Energy and the U.S. Protection Agency have joined with appliance manufacturers to institute the “Energy Star” program. Appliances displaying a yellow, white and blue energy star have been certified to significantly exceed the federal efficiency standards. They are deemed high efficiency appliances because of their reduced energy requirements.