Cold-water laundry detergent is a hot idea
A new formulation is tailored to consumers’ desires to save energy and money.
Household laundering takes a lot of energy—not even counting what’s required to haul the loads up and down stairs. In the U.S. and Canada, most of that energy is used to heat up water because laundry detergents have been designed to work with warm water. But earlier this year, Procter & Gamble (P&G) launched Tide Coldwater, a version of the popular laundry detergent designed for good cleaning in cold water. Why? Because consumers want to save on energy.
Environmental considerations have played a role in detergent formulation since the 1950s, when synthetic laundry detergents became popular. But components of detergents found their way through water treatment facilities. Specifically, alkyl benzene sulfonates were blamed for generating foams on rivers and lakes. In the 1960s and 1970s, more environmentally friendly products emerged, including detergents with biodegradable ingredients. Detergents were developed in the 1980s to work at slightly cooler temperatures. In the 1990s, low-sudsing varieties were developed for high-efficiency, horizontal-axis washers that use less water. Now, market research shows that consumers want to use cold water. Some want to save money and energy; others are just following the recommendations on their clothing labels.
Home laundering accounts for up to 36% of total household hot water use, according to a study by P&G and Exponent, a consulting firm, which will appear in the journal Integrated Environmental Assessment and Management. Citing information from Natural Resources Canada in 2004, the authors wrote, “On average, the thermal energy required to heat water using either gas or electric energy constitutes 80–85% of the total energy consumed per wash in conventional, vertical-axis (top-loading) washing machines.” Agitation in the washer accounts for the remainder. Reducing energy use also cuts down on CO2 emissions from energy generation at power plants, they added.
In a separate calculation, P&G claims U.S. consumers can save up to $63 per year in energy costs by washing in cold water. Their calculation is based on national average electricity costs in July 2004, a water heater set at 140 °F, 7 loads of laundry per week, and conversion from warm to cold water.
“Consumers want to save money on energy,” says Brian Sansoni, vice president of communications for the Soap and Detergent Association. “Companies are paying attention to that.”
“Consumers are happy with saving only when they can get optimal performance, so it’s important to have this formula such that it can still meet consumer needs but at lower temperatures,” says Darius Sabaliunas, author of the study and P&G section head in product safety and regulations affairs for household care. In terms of the environment, risk assessments show the new product is equally as safe as regular detergents, he adds.
So how cold is cold? Most detergents are geared for warm water that is 90 °F, but the industry standard for very cold water is 60 °F, says P&G senior engineer Michael Orr.
Coming up with an effective cold-water detergent was a challenge because the stain-fighting power of the ingredients in conventional detergent formulations decreases “by an order of magnitude for every 10 °F that you decrease the temperature,” says P&G senior scientist Donna Wiedemann, who formulated Tide Coldwater over the past 2 years.
Wiedemann explains that, like other detergents, Tide Coldwater has three groups of active ingredients—enzymes, surfactants, and builders. What’s different about Tide Coldwater? Its surfactant system is specialized for cold water, she says. Enzymes catalytically remove the soil and stains from fabric, surfactants emulsify and suspend the grime removed by the enzymes to prevent them from resetting on the clothes during the cycle, and builders deal with minerals in the water.
Tide Coldwater includes three enzymes: amylase breaks down starch; protease tackles proteins like grass and blood; and a proprietary enzyme attacks stains containing guar, which is used as a thickener in processed foods, says Wiedemann. The character of Tide Coldwater’s surfactant system is more hydrophobic than conventional detergents to help clean grease and oil, which is tougher in cold water, says Wiedemann. And that system is responsible for the lower viscosity of Tide Coldwater’s liquid form—not watering down of the formula, as some consumers have speculated, she adds. The builder system sequesters the minerals and transition metals from the water so they don’t interfere with stain removal.
Because Tide Coldwater has “about 20% more active ingredients” than Tide Regular, it costs more to use, says Wiedeman. Comparing bottles of equal volume and price, a consumer who follows the prescribed amount can do six more loads with Tide Regular than with Coldwater. It works out to a few more pennies per load.
Cold-water washing is becoming more popular and has environmental benefits, but it can have two problems, says S. Kay Obendorf, a professor of textiles and apparel at Cornell University. First, she says, in reality, cold water is whatever temperature runs from the tap. Where she lives in upstate New York, that temperature can hover near 32 °F during the winter. Second, clothes washed in cold water can come out of a wash “dirtier” than when they went in because live microbes can redeposit on the clothing. Even if cold-water formulations address these issues, she recommends washing heavily soiled items, such as diapers, in hot water with bleach.
Currently, the powder form of Tide Coldwater has an oxidation, or bleaching, component, but the liquid does not, Wiedemann notes.
Ian Hardin, a professor of textile sciences at the University of Georgia, also worries about cold-water washing, remarking that 60 °F is a “really low” temperature. “If you want better cleaning, higher temperature is always better,” he says, because the temperature of the water itself puts energy into the system and that energy is part of the solvation process that lifts the soil particles from the surface of the fibers. For example, he recommends hot-water washing and thorough drying if transferring bacterial or a viral illness through a household is a concern. “In creating a product like this, [detergent makers] are responding to the fact that they know there are a lot of people out there who want to do [a] cold-water wash.” In certain cases, it might work. “Compared to a generation ago or maybe two generations ago, most of us don’t get clothes nearly as dirty as we used to,” he says, so “if someone wants to cold-water wash [lightly soiled clothes], I’m sure these products will be just fine.”
Although nonprofit groups do not endorse products, some are promoting this concept. The Alliance to Save Energy, a U.S. energy-efficiency nonprofit organization, partnered with P&G to educate the public with the Coldwater Challenge. The Canadian Energy Efficiency Alliance, a separate organization, has an initiative called Switch to Cold.
Purex brand detergent is advertised as having a new formula that also works well in cold water, but the Dial Corp. did not respond to requests for more information.
