Assessing the Impact of Wash Water Temperature, Detergent Type and Laundering Platform on Basic Clothing Attributes. Abstract.

Assessing the Impact of Wash Water Temperature, Detergent Type and Laundering Platform on Basic Clothing Attributes Elizabeth P. Easter, PhD; Cinnamon, Meredith & Baker, Erin; University of Kentucky, Lexington, KY 40406 Abstract The objective of the consumer laundry research study was to determine the impact of wash water temperature, detergent type and laundering platform on basic clothing attributes. To determine the effects of top and front loading washing machines, cold and warm water wash temperatures and detergent types on home laundered garments by assessing color change, dimensional stability, pilling, moisture content and residual moisture content and stain removal. Testing was conducted on consumer loads of denim, towels, khakis, polos, and mixed consumer loads. Each load type was subjected to thirty wash and dry cycles. Evaluations of the loads were conducted prior to testing (when applicable to test method), as well as after one, five, ten, fifteen, and thirty wash and dry cycles. Key Terms Laundry Platform, Detergent, Wash Temperature, Clothing Attributes Introduction Purpose of the Research The purpose of the laundry study was to determine the impact of wash water temperature, detergent type and laundry platform on basic clothing attributes. Life cycle assessments of clothing and textile products highlight the potential for reduced environmental impact of HE washer and doing the laundry in cold water. 1 Care labels are designed with specific laundering instructions that are meant to produce the least amount of harm to the clothing to allow for best clothing performance. Before recommendations on how to launder cotton with minimal environmental impact are made there is a need to evaluate the impact of these recommendations to ensure that performance and wear life are not greatly degraded. Objectives of the Research The objectives of the laundry study were to evaluate the effects of cold versus warm water washing, to evaluate the effects of detergent types, and to determine the effects of top and front loading washers and matching dryers on home laundered garments. The effects of cold versus warm water washing temperature were evaluated by measuring dimensional stability, colorfastness to laundry, and stain removal. The detergent types included regular formulations for the top load washer and high efficiency for the front load washer. A standard control liquid detergent was used on both the front and top load washers as a control. In order to determine the effects of top and front loading washers and matching dryers, towel absorbency, pilling

propensity, stain removal, remaining moisture content, and residual moisture content were examined. Properties Evaluated The properties of abrasion resistance, colorfastness to laundry, color transfer, dimensional change, residual moisture, remaining moisture, smoothness retention, soil release, and towel absorbency were assessed for most clothes loads. Soil release and color transfer were not performed on the towel or jeans loads. Towel absorbency testing was performed on the towel loads only. Review of Literature Laundering Platform Traditionally, laundering platforms are found in two basic designs. Vertical axis, or top loading washers, have a central agitator and currently make up 75-85 percent of all washers sold in the United States. 2 Most vertical axis machines suspend the clothes in a tub of water for washing and rinsing, a process which typically requires at least 40 gallons of water per load. Horizontal axis, or front loading washers, tumble clothing through a small bath of water using between 20 and 60 percent less water than a conventional top loading machine. 2 The majority of U.S. appliance manufacturers now offer high-efficiency (HE) machines in both horizontal and vertical axis designs. These high-efficiency machines require less water intake and have a reduced environmental impact by saving water and saving energy. In order to accelerate the HE washer market, the Department of Energy conducted a field evaluation of HE washers. 2 The hypothesis - that a changeover from conventional, vertical axis washers to the high-efficiency, horizontal axis designs would decrease the water and energy consumption - was substantiated. 2 In 2007, the Clothes Care Research Center (CCRC) conducted a study to investigate how the new Department of Energy requirements for reduced water and energy consumption would affect consumer satisfaction regarding the laundry process. 2 The CCRC found that reducing the water usage does not affect the appearance factors of color retention, pilling and smoothness, regardless of fiber content. 2 However, the reduced water usage did increase the potential for color transfer between garments in the load. This was measured by adding white fabrics to a typical dark load. 2 Wash Water Temperature According to the report, Energy Efficient Laundry Process, approximately 50 percent of all energy consumed during the laundry process comes from heating the water. 3 One way to reduce energy usage is to lower the water temperature. Historically, in order to obtain sanitation and cleaning of clothing during the laundering process, hot water temperatures of at least 160 F were used. In the early 1990s, household water heaters were manufactured with a preset of 120 F. 5 This reduction in hot water temperature resulted in a significant energy and monetary savings for consumers. 2 Studies have also shown that consumers do less than ten percent of all clothes loads in hot water. 2 Consumers want to use cold water in order to save money and energy or due to the recommendations on their clothing labels. 4

Results of a study examining the effect of lowering the temperature of wash water from 90 F to 70 F shows that the reduction in water temperature does not affect color retention, pilling, and soil redeposition. 6 The most significant impact of this reduction in temperature was on stain release in which warm water washing was more effective. If the temperature of the wash was lowered an additional 10 F, color retention, smoothness, and stain release were adversely affected. 6 Detergent Type Consumers can find a broad array of detergent brands claiming special qualities in every supermarket and shop. 7 Laundry detergents generally come in two forms: powders (including tablets) or liquids. 7 In 1990 liquid laundry detergents were a fast growing market segment and soon consumed 50% of the market share. 7 Consumers found that liquids were easier to use and dissolved better into consumer wash water. Cold water detergents were reintroduced to the U.S. detergent market in 2005. These detergents, designed to work efficiently in cold water, also provide savings to consumers by reducing energy costs. 8 It is estimated that the average consumer can save $63 a year by switching to cold water versus warm water in their laundry. 4 Switching to cold water provides monetary savings as well as energy savings. A study completed by Bruce Cameron at the University of Wyoming found that there is no apparent advantage to using cold water detergents. 7 Considering all detergent types tested, the cold water detergent gave slightly higher whiteness indices than the regular detergent with no bleach. 7 The cold water detergents over all were no better at whitening than either detergents without bleach or detergents containing nonchlorine bleach in cold water. 7 Cold water detergents are predicted to yield improved results if the textiles are not heavily soiled or if a prewash treatment is used. This study was not designed to answer this question. 7 In fact; textiles washed in cold water may come out dirtier than before due to redeposition of live microbes. 4 Most soils will dissolve more readily the higher the temperature, therefore, textiles are going to clean better with increasing temperature. 7 Cameron states that further research in evaluating laundering in cold water needs to be conducted. 7 Methodology Experimental Methodology For this study, five consumer load types were evaluated including towel loads, jean loads, khaki loads, polo loads, and mixed consumer loads. There were two washer platforms evaluated: front and top loading washers with matching dryers. Two water temperatures were evaluated: warm water (90 F) and cold water (60 F). Four types of widely available high end commercial detergent was used including regular liquid (top loading washer), coldwater liquid (top loading washer with cold water cycle), high efficiency liquid (front loading washer), and high efficiency coldwater liquid (front loading washer with cold water cycle). A standard liquid detergent was used as a control for every cycle set up.

Experimental Configuration Eight total load configurations were tested for each of the five consumer load types for a total of 40 load variations. The replications of warm water and cold water washes were repeated on both front and top load washers. For each warm and cold wash, the corresponding liquid detergent was used as well as the standard control detergent. This was repeated for both the top and front loading washer platforms. The eight load configurations can be seen in the figure below. Fig. 1 Experimental Load Configuration Washer and er Conditions Each load type was subjected to the series of wash and dry cycles for a total of 1200 cycles throughout the entire consumer laundry study. Each load was evaluated for the performance properties after one, five, ten, fifteen, and thirty wash cycles. The following cycle conditions were used for the top and front loading matching washer and dryer pairs. Front Load Wash Cycles Cycles Load Type Load Weight (lb) Cycle Time (min) Wash Cycle Wash Temp. Soil Level Detergent/ Spin Cold Speed load* (g) Cycle (min) Cycle Temp. Sensor Level Extra Towels 8 60 Colors/Normal Cold Normal High 55±1 43 Cotton High More Extra Jeans 8 60 Colors/Normal Cold Normal High 55±1 40 Cotton High Wrinkle Khakis 8 54 Wrinkle Free Cold Normal High 55±1 53 Free Medium More Knit Golf Active Shirts 8 54 Active Wear Cold Normal High 55±1 57 Wear Medium Mixed 10 60 Colors/Normal Cold Normal High 75±1 51 Mixed High Fig. 2 Front Load Washer and er Condition

Top Load Wash Cycles Cycles Detergent Load Wash Wash Load Soil per Load Type Weight Cycle Temp. Size Level Warm (lb) load (g) Cycle Temp. Cotton Optimum Towels 8 Cotton Cold Large Medium 65±1 High Jeans 8 Cotton Cold Large Medium 65±1 Cotton Optimum High Khakis 8 Easy Care Cold Large Medium 65±1 Easy Care Less Medium Knit Golf Shirts 8 Easy Care Cold Large Medium 65±1 Easy Care Less Medium Extra Cotton Optimum Mixed 10 Cotton Cold Large Medium 80±1 High Fig. 3 Top Load Washer and er Conditions Load Compositions Each load type included products of mixed fiber contents except for the towel loads which were made up of 100% cotton bath towels. The jean loads consisted of 100% cotton jeans and cotton/polyester blended jeans. The khaki loads were cotton/polyester blended khakis, cotton/spandex blended khakis, and wool/polyester blended khakis. The knit golf shirt or polo loads included 100% cotton polos, cotton/spandex blend polos, 100% polyester polos, and cotton/polyester blend polos. The mixed consumer load consisted of dress shirt blends, athletic t- shirt blends, athletic nylon shorts, khakis, and knit golf shirts. The detailed load compositions are shown in the chart below. Load Item Fiber Content #/Load Jeans Store Retailer Men's 100% Cotton Jeans 100% Cotton 3 Jeans Catalog Brand Women's Jeans 52% Baumwolle (Cotton)/48% Polyester 3 Khakis Catalog Brand Women's Cotton Pants 97% Cotton/3% Spandex 3 Khakis Store Retailer Men's Polyester/Wool Pants 60% Polyester/40% Worsted Wool 3 Khakis Store Retailer Cotton/Polyester Pants 54% Cotton/36% Polyester 3 Knit Golf Shirts Catalog Brand Men's 100% Cotton Polo 100% Pima Cotton 4 Knit Golf Shirts Catalog Brand Women's Cotton/Spandex Polo 97% Cotton/3% Spandex 4 Knit Golf Shirts Store Retailer Polyester Mesh Polo 100% Polyester 4 Knit Golf Shirts Store Retailer Cotton/Polyester Polo 60% Cotton/40% Polyester 3 Towels Store Retailer 100% Cotton bath Towel 100% Cotton 9 Mixed Load Store Retailer Oxford Cotton/Polyester Dress Shirt 65% Cotton/35% Polyester 2 Mixed Load Store Retailer 100% Cotton Dress Shirt 100% Cotton Broadcloth 2 Mixed Load Store Retailer Cotton/Poly Dress Shirt 55% Cotton/45% Polyester 2 Mixed Load Store Retailer Kids 100% Nylon Short 100% Nylon 2 Mixed Load Store Retailer Polyester Blend Shirt 95% Polyester/5% Elastane 2 Mixed Load Store Retailer Cotton/Poly Blend T-Shirt 60% Cotton/40% Polyester 4 Mixed Load Store Retailer Men's Polyester/Wool Pants Same as Above 1 Mixed Load Store Retailer Cotton/Polyester Pants Same as Above 1 Mixed Load Catalog Brand Women's Cotton/Spandex Polo Same as Above 2 Mixed Load Store Retailer Cotton/Polyester Polo Same as Above 2 Fig. 4 Load Compositions

Results The results will present and discuss the findings based on clothing attributes that impact appearance, comfort and/or durability and serviceability. The results of conducting a statistical analysis will highlight the significant findings of the study. Pilling Propensity The results of evaluating pilling propensity showed that cold water wash temperature resulted in the lowest degree of pilling for the mixed loads, khaki loads, and towel loads. Jeans and polo loads exhibited the lowest degree of pilling in the warm water loads. The table below gives the load type and the corresponding load configurations (laundering platform, water temperature, and detergent type) in which the lowest degree of pilling was exhibited. This configuration was not necessarily used in conjunction with one another (i.e., Coldwater liquid detergent with a warm water temperature cycle). Pilling is scored on a rated scale from 1 to 5 with 5 meaning no pilling and 1 meaning severe pilling. Table I. Pilling Propensity Load Type Pilling Score Washer Water Temp. Detergent Towels 5 Front Cold HE Coldwater Jeans 5 Front & Top Warm Regular & HE Liquid Khakis 5 Front Cold Coldwater Liquid Polos 5 Top Warm Coldwater Liquid Mixed 4.5 Front Cold Standard Control Colorfastness to Laundry The colorfastness to laundry testing showed that top load washer and warm water loads had the greatest degree of colorfastness for the mixed, khaki, and towel loads. Jeans loads exhibited the greatest degree of colorfastness in the front load washer and cold water loads. The table below gives the load type and corresponding load configuration in which the greatest degree of colorfastness was exhibited. This configuration was not necessarily used in conjunction with one another. Colorfastness is rated on a scale from 1 to 5 with 5 meaning no change in color and 1 meaning severe change in color. Table II. Colorfastness to Laundry Load Type Colorfastness Washer Water Temp. Detergent Towels 3.33 Top Warm Coldwater Liquid Jeans 2.67 Front Cold Coldwater Liquid Khakis 4.83 Top Warm Coldwater Liquid Polos 5 Front & Top Cold Coldwater Liquid Mixed 4 Top Warm Standard Control Color Transfer Color transfer testing showed that front load washer and cold water loads had the lowest degree of color transfer for the polo and khaki loads. Mixed loads exhibited the lowest degree of color transfer in the top load washer and warm water loads. The table below gives the load type and

corresponding load configuration in which the lowest degree of color transfer was exhibited. This configuration was not necessarily used in conjunction with one another. Color transfer is rated on a scale from 1 to 5 with 5 meaning no color transfer and 1 meaning severe color transfer. Table III. Color Transfer Load Type Color Washer Water Temp. Detergent Transfer Khakis 5 Front Cold HE & HE Coldwater Liquid Polos 5 Front Cold HE Coldwater Liquid Mixed 5 Top Warm Coldwater Liquid & HE Liquid Dimensional Change Dimensional change testing showed that HE Coldwater detergent had the lowest dimensional change for the towel, jeans, khakis, and mixed loads. Polo loads exhibited the lowest dimensional change in the HE liquid detergent loads. Cold water loads exhibited the lowest dimensional change for all load types. Dimensional change was measured at each wash cycle interval and is calculated as a percentage of shrinkage or growth. The higher the dimensional change value, the more shrinkage or growth occurred. The table below gives the load type and corresponding load configuration in which the lowest dimensional change occurred. This configuration was not necessarily used in conjunction with one another. Table IV. Dimensional Change Load Type % Change Washer Water Temp. Detergent Towels -6.9% Front Cold HE Coldwater Liquid Jeans -1.86% Front Cold HE Coldwater Liquid Khakis -0.16% Top Cold HE Coldwater Liquid Polos -1.35% Top Cold & Warm HE Liquid Mixed -0.66% Front Cold HE Coldwater Liquid Residual and Remaining Moisture Content The findings from residual and remaining moisture content showed that for all load types, the most common interaction occurred between water temperature and detergent type. The table below gives the load type and corresponding load interactions for moisture content. This configuration was not necessarily used in conjunction with one another. Table V. Moisture Content Load Type Interactions Washer Water Temperature Detergent Type Towels X X Jeans X X Khakis X X X Polos X X Mixed X X

Smoothness Retention Smoothness retention testing showed that cold water loads exhibited the greatest degree of smoothness retention for all load types. Smoothness retention is rated on a scale of 1 to 5 with 5 meaning no wrinkles and 1 meaning severe wrinkles. The table below gives the load type and corresponding load configuration in which the greatest degree of smoothness retention occurred. This configuration was not necessarily used in conjunction with one another. Table VI. Smoothness Retention Load Type Smoothness Washer Water Temp. Detergent Jeans 4 Top Warm Coldwater Liquid Khakis 4 Front Cold HE Coldwater Liquid Polos 5 Front Cold HE Liquid Mixed 3.63 Top Cold HE Coldwater Liquid Soil Release Soil release findings show that front washer and warm water loads have the greatest degree of soil release for polo, khaki, and mixed loads. Slight interaction occurred between water temperature and detergent type for polo loads. Soil release is rated on a scale from 1 to 5 with 5 meaning complete stain removal and 1 meaning no stain removal. The table below gives the load type and corresponding load configuration in which the greatest degree of soil release occurred. This configuration was not necessarily used in conjunction with one another. Table VII. Soil Release Load Type Soil Release Washer Water Temp. Detergent Khakis 4.4 Front Warm HE Liquid Polos 5 Front Warm HE Liquid Mixed 5 Front Warm Regular Liquid Towel Absorbency Towel absorbency testing found that top load washer, cold water, and Coldwater liquid detergent loads had the greatest degree of towel absorbency. The HE Coldwater detergent load had the lowest degree of towel absorbency. Towel absorbency measures the remaining water not absorbed by the towel in ml. An average is given for the front and back side of the towel. The table below gives the corresponding load configuration in which the greatest degree of towel absorbency occurred. This configuration was not necessarily used in conjunction with one another. Table VIII. Towel Absorbency Load Type Absorbency Washer Water Temp. Detergent Towels 5.83 Top Cold Coldwater Liquid

Conclusions Based on the results of this study, the following conclusions were established. In examining pilling propensity, cold water loads exhibit the least amount of pilling for khaki pants, towels, and mixed consumer loads. Washing platform, water wash temperature, and detergent type all interact to influence the degree of pilling. The vertical axis, top load washing machine has the greatest degree of colorfastness for all load types except jeans. The HE Coldwater liquid detergent has the greatest colorfastness regardless of laundry platform or water temperature for all loads except the mixed consumer loads. Color Transfer is influenced by washing platform, water wash temperature, and detergent type for all load types. Front load washer and cold water loads exhibit the least amount of color transfer for the polo and khaki loads. The mixed consumer loads exhibit the lowest degree of color transfer in the top load washer and warm water loads. HE Coldwater loads exhibit the least amount of dimensional change for all load types except polos. For remaining and residual moisture content, water temperature and detergent type are the most common influential interaction for all load types. Cold water and HE Coldwater detergent loads exhibit the greatest smoothness retention. Garments exhibit greater soil release when washed in regular liquid detergent or HE liquid detergent, not coldwater detergents. The greatest towel absorbency occurs in cold water loads and with the use of coldwater detergent. Acknowledgements The authors would like to acknowledge Cotton Incorporated for their support, funding, and commitment to this study. References 1. Cotton Incorporated, The Life Cycle Inventory & Life Cycle Assessment of Cotton Fiber & Fabric. The Cotton Foundation. 2011, pp1-4. http://cottontoday.cottoninc.com/sustainability-about/lci-lca-handout/lci-lca- Handout.pdf 2. Easter, E., Environmental Impact of Laundry, Future Fashion White Papers, 2007, pp94-104. 3. Richter, T. Energy Efficient Laundry Process, Final Project Report for the Department of Energy, November 1, 2011-December 31. 4. Petkewich, R., Cold-water Laundry Detergent is a Hot Idea, Environmental Science & Technology Online News. September 21, 2005. 5. Cotterill, G., et. al., Clothes Care Labels-Recommended Temperatures for Wash Cycle. 6. Easter, E. & Ankenman, B. Impact of Low Energy/Low Water on Clothes Care. Book of Papers: 2006 International Conference & Exhibition. 7. Cameron, B., Laundering in Cold Water: Detergent Considerations for Consumers, Family and Consumer Sciences Research Journal, Vol. 36, No. 2, December 2007, pp151-162.

8. McCoy, M., Soaps and Detergents: Specialty chemical makers seek business both with cleaning product innovators and the companies that follow them, Chemical and Engineering News, Vol. 77, No. 5, 2006, pp13-19. Author Elizabeth Easter, 318 Erikson Hall, University of Kentucky, Lexington, KY 40504, USA; phone +1 859 257 7777; fax +1 859 257 1275; eeaster@uky.edu