Residential Clothes Washer Introduction
Washing laundry is a large water user in the average home; accounting for 15% to 40% of the overall water consumption inside the typical household of four persons. Before new standards were adopted in 2010, traditional clothes washers used approximately 30 to 45 gallons (113.6 L to 170.3 L) of water per load. A typical family of four using a standard sized clothes washer will generate more than 300 loads per year. This equates to a regular washer consuming approximately 12,000 gallons (45.4 m3) of water annually. High-Efficiency Washers (HEW) significantly reduce this water use by more than 6,000 gallons per year (22.7 m3), save energy, clean the clothes better, use less detergent, and reduce fabric wear.
Listing of High Efficiency Clothes Washers
The most recent listing of high-efficiency clothes washers is provided here:
Energy Star Products > Clothes Washers for Consumers (Link)
CEE Clothes Washer Qualifying Product List (Link)
CEE Specifications for Residential Clothes Washers (PDF)
Until recently, the traditional top-loading clothes washer, using a vertical-axis drum, changed little from the first automatic washers designed in 1947. Water and energy efficiency has always been hampered in the traditional vertical-axis design because the clothes needed to be freely suspended in the water to facilitate the churning required to clean the fabric. Horizontal-axis washer designs were once the only alternative to achieve ultra high water and energy efficiencies because the rotating drum lifted the clothes in and out of the wash water. Recent developments now offer two significantly different designs of vertical-axis washers, with significantly different results in water use and performance. The advanced designs replace the use of a central agitator with impeller wash plates that can churn the water and clothes without the need for additional water to suspend the clothes in the wash water.
Traditional Vertical-Axis with Agitators
Most vertical-axis designs require enough water in the drum to suspend the fabric in the soapy water while the central agitator churns the clothes to help remove dirt and stains. The large amount of water required to suspend the fabric in the tub limits the ability for this type of washer to efficiently use water. Historically, traditional vertical-axis washers consumed 45 gallons (170.3 L) per load, though newer models of the past few years have reduced this to less than 30 gallons (113.6 L) per load. The advent of horizontal-axis washers and recent innovations in ultra high-efficiency vertical-axis washers offers consumers new choices in clothes washers that use less water and energy while improving cleaning performance and preserving the quality of the fabric.
Advanced Vertical-Axis with Wash Plates
Recent developments have led to the development of ultra high-efficiency top-loading clothes washers. By replacing the traditional agitator with wash plates at the bottom of the tub basket, the newest designs of vertical-axis washers offer ultra high-efficiency by utilizing a slurry of water and detergent for the clothes to gently churn. The result is substantially less water and energy use while cleaning clothes better with less wear and tear on the fabric. These machines typically consume approximately 15 gallons (56.8 L) per load. This is comparable to the efficiency of front-load washers (below).
Like the advanced vertical-axis washers, horizontal-axis washers (predominately front-loading) facilitate greater water efficiency because the clothes no longer need to be suspended in water to allow for the agitation required to remove dirt from the fabric. The rotating drum constantly lifts the clothes in and out of the water; effectively dissolving and removing the soil and stains from the clothes. This process is proven to be very effective in cleaning the clothes, and is gentle on the fabric. Most horizontal-axis washers use less than 15 gallons (56.8 L) of water to wash. The most efficient horizontal-axis washers use less than 3 gallons (11.4 L) per cubic foot of capacity.
Water Efficiency of Washers
Because washers come in various sizes and capacity, the water efficiency of clothes washers is rated using the term "Water Factor" to accurately compare water use. Water Factor (WF) is measured by the quantity of water (gallons) used to wash each cubic foot of laundry. The smaller the WF rating, the more water efficient the clothes washer. A typical residential clothes washer has a capacity of approximately 3.5 cubic feet, though sizes range from 1.7 cubic feet (48.13 L) to more than 4.2 cubic feet (118.9 L) for the extra-large capacity machines. The WF provides a means to directly compare water efficiency of different sized machines.
Washer A uses 32 gallons of water per load (wash and rinse cycles) with a 4 cubic foot capacity of laundry; thus, has a WF rating of 8 (32÷4=8).
Washer B uses 30 gallons of water (wash and rinse cycles) with a 2.5 cubic foot capacity; thus, has a WF rating of 12 (30÷2.5=12).
Washer A uses water more efficiently (WF=8) than Washer B (WF=12). While Washer A uses slightly more water per load, it can clean 40% more clothes per load.
When buying a new machine, finding the WF rating of a clothes washer is not always easy. Though manufacturers measure WFs for each model of washer, manufacturers are not required to display the rating on the machine. Fortunately, the Energy Star Program reports WFs and energy use for nearly every HEW in the market at: Energy Star Products > Clothes Washers for Consumers