Product Definition/Scope - Clothes washers included in this analysis include top- and front-loading machines of any size, designed for residential use. Coin-operated and industrial clothes washers were not included.

Performance Criteria/Parameters Used – In developing the list of products that are eligible for Top Ten USA we evaluated products based on the following criteria:

• Modified energy factor (MEF) – This metric is calculated by dividing the capacity of the machine by the sum of the energy used by the washer, the dryer (to remove the remaining moisture content), and the hot water used to wash the clothes.
• Water factor (WF) – This metric is calculated by dividing the weighted per-cycle water consumption by the capacity of the clothes washer.

Test Methods – We used the following test methods for measuring the performance criteria listed above:

• U.S. Code: 10 CFR 430, Subpart B, Appendix J1

Market Segmentation – Clothes washers were split into two size classes: greater than 2.5 cubic feet, and less than 2.5 cubic feet.

Data Source – We used manufacturer reported data from the EPA ENERGY STAR website.

Market Availability – In order to be qualified the model must be currently available to consumers through retail outlets such as department stores, big box stores, independent appliance retailers and/or on-line retailers.

Families of Similar Products – Multiple products with identical MEF and WF ratings were considered “tied”, and all products at that level were listed.

Product Ranking – Products were ranked by their MEF. Only machines that met the CEE Tier 2 WF criteria (WF ≤ 7.5) were included in the list.