Newly formulated laundry detergents can wash most clothes perfectly well in cold water, manufacturers say, but customers are stubbornly refusing to turn down the temperature. Although some of these detergents have been available for several years, customers cling to mom’s age-old advice that hot water washes best — squandering energy and contributing to greenhouse gas emissions.

Even in Germany, where consumers tend to be more environmentally attuned than in the United States, manufacturers have discovered that cold-water washing is such a hard sell that they have relegated claims about it — and the attendant green benefits — to the fine print, choosing to emphasize other attributes.

“For selling, it is much more effective to focus on stain removal and whiteness, performance and price,” said Dr. Thomas Mueller-Kirschbaum, a senior vice president for research and development at Henkel, the German company that markets cold-water formulas under the Persil and Purex brands. “In market research, when you ask consumers, they currently don’t see the immediate benefit of saving energy.”

Of course, some consumers have long preferred to wash their clothes in cold water to prevent them from shrinking or the colors from fading, and many others wash darks or delicate clothes on the cold cycle.