In considering the purchase of a washing machine there are several factors which are important for energy efficiency and cost savings--mainly the amount of water to be heated during its operation and the amount of water extracted during its final spin cycle.
The US Department of Energy's Energy Star Program has measured energy efficiency for washing machines and other major appliances, TVs, VCRs, heating and cooling equipment, residential light fixtures, office equipment, windows, and newly built homes. These products were tested for energy efficiency and operational cost factors. See www.energystar.gov/products for Energy Star products, retail stores selling them, and other related information.
Vertical vs. Horizontal Axis Washers
Conventional washers (vertical axis with a central agitator) suspend clothes in a tub of water for the cleansing and rinsing processes. This method uses, on average, about 40 gallons of water for each load. Since each US household washes approximately one load per day, this equals nationally about 35 million loads each year and highlights the fact that clothes washers are one of the highest end-users of water in American homes.
Alternatively the horizontal axis clothes washer repeatedly tumbles (instead of the agitation process) clothes through a small pool of water in the bottom of the tub. This process reduces the amount of water needed for the cleaning process. The US Department of Energy funded a real-world testing of these machines in Bern, Kansas, population 204. After an initial two months of data gathering on participant/laundry profiles, the participants' washing machines were replaced with 103 high-efficiency horizontal-axis washers for three months to measure energy efficiency and cleaning thoroughness.
Results of this study showed an impressive decrease in both water and energy use. Using the h-axis washers, the average water use of 41.5 gallons per loan fell to 25.8 gallons, a savings of 38%. Energy use, which included washer processing and energy used for heating water fell by 58%. An additional savings was found since the moisture content of each load was lessened by approximately 7%, shortening drying time. Additionally, the study participants reported the cleaning performance of the h-axis washers was superior to their original washers.