“I Prefer 30°” Celcius: Consumer Messages to Reduce Carbon Emissions

Executive Summary

I Prefer 30

Since 1997, large European detergent manufacturers, individually, as well as through their industry association, have developed various consumer campaigns to urge consumers to reduce washing temperatures for laundry. These campaigns have included:

  • TV advertising for their individual brands
  • industry-wide on-pack messages
  • a coordinated, multi-sector, pan-European campaign called “I Prefer 30°”

Washing laundry at 30 degrees Celsius (i.e., 86 degrees Fahrenheit) would reduce carbon emissions, as well as save money for consumers, but the initiatives have had limited success.

This working paper analyzes the factors affecting the relative success of these voluntary business initiatives.

Six types of benefits have been tested:

  1. improving cleaning performance
  2. benefitting the environment
  3. saving energy or emissions
  4. improving convenience and ease of use
  5. improving clothing care
  6. saving money

According to interviews with 23 marketers of laundry cleaning products: “Saving money is considered least important as a motivating message” despite the potential for $46 in annual savings.

The study’s authors conclude: “Consumers’ behavior has been driven by perceived cleaning performance and value for money of detergents, not by lower environmental impact or saving money on energy. Following P&G’s Turn to 30 campaign’ for its Ariel brand, other brands subsequently have not led with the benefits of reduced washing temperature in their advertising. This is in part because it would not be competitively distinctive, but also that it is believed that this messaging would not increase short-term sales, nor be effective in changing behavior.”

Research Notes

Policy Implications

According to the authors: Washing with household laundry equipment makes a 2.4% contribution to global warming. Along with other consumer practices, domestic laundering needs to become substantially less carbon intensive, in order to meet EU policy targets to reduce greenhouse gas emissions by 20% by 2020.

Literature Review: Highlights

  • From Young et al.’s (2010) consolidation of the literature: Green values play a relatively weak influence on the purchase decision process in the context of habits, brand strength, demographic characteristics, lack of information, lifestyles, personalities and complexities of trading off between different ethical factors.
  • Abrahamse et al.’s (2005) review of thirty-eight evaluations: Consumer messaging interventions to influence behavior change for reduced carbon emissions finds only isolated successes.

I Prefer 30° – Close Out Report

The I Prefer 30° campaign organizers published their own report, which you can download here:

I Prefer 30 Campaign Report

While the organizers deemed the campaign a success from the point-of-view of participant cooperation and lessons learned, the data shows the campaign was ineffective at changing consumer behaviors.  In fact, average washing temperature went up between 2011 and 2014:

Washing Temperature by Country

Insights from Procter & Gamble and Unilever:

In 2012, Triple Pundit reported the following stats from Peter White, Director of Global Sustainability for P&G: About 10-15 percent of consumers are very green aware and “are prepared to pay more” for more sustainable products. For another 15 percent, the call to save the planet “totally passes them by.” In the middle is the “sustainable mainstream,” consumers who will choose greener products, but only if it is made easy for them. Primarily, this means they will not pay a premium.

In an October 2008 report by Campaign, P&G asserted that Ariel laundry detergent’s Turn to 30 campaign increased the number of consumers washing on low-energy programs by up to five times, and that existing Ariel customers are twice as likely to opt for these cycles as the average consumer.

However, A Unilever marketing director has publicly stated that the P&G Turn to 30 campaign for Ariel laundry detergent did not change behavior (Charles, 2010).  He stated that this view was derived from market research carried out by Unilever, in which consumers placed electronic chips in their washing machines to measure the temperature and length of washes.

Publication Date



Centre for Climate Change Economics and Policy Working Paper No. 290


Elizabeth Morgan, Tim Foxon, and Anne Tallontire

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