Life-Cycle Optimization of Residential Clothes Washer Replacement

By April 1, 2006Library

By Richard Bole ’06

Abstract: The energy efficiency of the average clothes washer in the United States improved by 88.4% from 1981 to 2003 (AHAM 2005). Replacement of old vertical-axis washers with new horizontal-axis washers results in decreased operating costs, both environmental and economic. But replacement also results in one-time financial and environmental impacts from purchasing, manufacturing and disposition. The purpose of this study is to quantify this trade-off and determine optimal replacement intervals for residential clothes washers. The Life-Cycle Optimization (LCO) model employed to answer this fundamental research question uses as inputs separate Life-Cycle Inventory (LCI) and Life-Cycle Cost (LCC) profiles for each model year clothes washer from 1985-2020. These profiles represent four life-cycle phases of a washer: Material production, manufacturing and assembly, use, and end-of life management. The results of the LCI and LCC studies showed that the use phase of the washer’s life cycle accounts for 96-99% of energy, carbon dioxide emissions and water use, but just 61%-86% of total costs over an anticipated 20 year life. From an energy or carbon dioxide emissions perspective, any average washer, regardless of model year, should be replaced with a new horizontal-axis washer in 2006, 2011 and 2016. From a water use and cost minimization perspective an average washer should be immediately replaced with a horizontal-axis washer which should be held until the end of the study period.

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