Sustainability and Cold Water



The New York Times (September 17, 2011) had a great article by Andrew Martin and Elisabeth Rosenthal ("A Dash of Cold Water: Green Detergents Battle for a Share of Laundry Day") that highlights several key issues relating to sustainability.  Sustainability is the ultimate two sided coin issue (really three - - economic, environmental, and social).

Nothing illustrates the three sides better than the washing machine and dirty clothes.  On one side is the goal of a more sustainable alternative to washing clothes in heated water.  The paradox of hot water - - about 3/4 of the energy use and greenhouse-gas emissions from washing a load of laundry come from heating the water - - a practice the most people should find wasteful and unnecessary.  Into this void has stepped cold-water detergents - - such as P&G's Tide Coldwater.  On the other side of the coin are traditions and social norms - - clean clothes require hot water.  Always has, and always will.

The article points out several points that apply to a wide variety of sustainability issues that engineers are going to have to tackle.  These are as follows:

• Globally, 38% of laundry loads are done in cold water.  P&G thinks this can improve to 70% by 2020.
• Clean clothes require three inputs - - thermal energy, mechanical energy, and chemicals (as a teenager, my mother would have added a fourth - - motivation).  If you eliminate one, such as hot water, one of the other inputs needs to have a greater impact (independent of motivation).  Tide Coldwater, with different enzymes and surfactants, works better in cold water.
• Tide Coldwater ranks as a top detergent in terms of performance.
• Cold water and hot water detergents are the same price.
• German consumers have been much more skeptical with cold water detergents, sales are languishing (even with more "green" cultural attitudes).
• Typical German comment - - "I'm just skeptical that normal dirt and spots can be washed out with cooler water."  A response from a U.S. customer at Target - - "I find that sometimes I wash it in cold and have to wash it again in warm water" (to which my mother would yell - - "too much motivation").

Cold water washing runs into all of the elements of the Triple Bottom Line (economic, environmental, and social) and the fundamental goals of sustainability.  Clearly the economics are better - - hot and cold detergents are the same price with lower energy costs for the cold water brands.  Cold water washing does not have performance deterioration.  The environment is positively impacted due to lower energy costs (as long as the reformulation of cold water detergents does not have a manufacturing impact - - a complete life-cycle assessment would be necessary).  The major issue and problem is social - - cold water runs into the historic norms of hot water performance.  It runs into the marketing problem that without greater improvements in the economic and environmental awareness and performance at the individual level - - society as a whole is probably going to be reluctant to change.