Technological breakthroughs

Why Doing Laundry Is an Environmental Issue

Washing clothes may sound like a simple household chore, but it is actually one of the most energy- and water-intensive activities in the home. Across the European Union, laundry accounts for an estimated 24.2 TWh of electricity and 1.5 km³ of water every year. Life-cycle analysis (LCA) studies show that most of laundry's environmental impact — roughly 60% — comes from the in-home use phase, driven mainly by the energy needed to heat wash water, while the detergent's ingredients themselves account for only about 20% of the impact. Since around 80% of a washing machine's energy use goes toward heating water, lowering the wash temperature offers both environmental benefits and cost savings for consumers.

Over the years, washing machine manufacturers have cut water and energy use by at least half. Detergent makers have also made progress, notably by adding enzymes that clean effectively even at low temperatures, alongside a shift toward more compact detergent formats that reduce the environmental footprint of packaging and transport.

Another approach to improving laundry sustainability is the rise of "eco-brand" detergents, designed to meet third-party criteria and signal an environmentally friendly choice to consumers. In Europe, the most recognized such certification is the EU Ecolabel, which restricts the type and concentration of ingredients allowed based on a hazard-based approach — a constraint that can sometimes reduce a product's cleaning performance.

When "Green" Comes With a Performance Trade-off

Earlier research suggests that most consumers — somewhere between 75% and 80% — are unwilling to trade cleaning performance for a more "environmentally friendly" product. Consumers also tend to be skeptical of eco-labelled products, assuming they come at the cost of lower quality. Since the primary goal of doing laundry is still to get clothes clean, researchers hypothesized that a lower-performing detergent might push consumers toward compensatory behaviors — washing at higher temperatures, washing smaller loads, or using more detergent per load — all of which could increase the overall environmental footprint of the laundry process, potentially outweighing the benefits the "green" formulation was designed to provide.

Notably, industry survey data shows that earlier progress in encouraging cold-water washing across Europe has stalled. The average wash temperature in the EU fell from 48°C in 1997 to 41°C in 2011, but has since crept back up to 42.4°C by 2020 — suggesting that real barriers still stand in the way of consumers sustaining a cold-water washing habit.

Study Design: A Blind Trial With Real Households

To dig deeper into this question, a research team — including authors from Procter & Gamble's European operations and the University of Bonn in Germany — ran a months-long behavioral study with 118 French consumers who completed the full study.

All participants started out using a liquid-tablet detergent marketed as "high performance." After a four-week baseline period during which they used their own usual product, participants were randomly split into two groups of 59 each and given one of two products in unbranded, neutral packaging for eight weeks:

• Control group: continued using a standard "heavy duty" high-performance detergent, optimized for cleaning power.
• Test group: switched to a detergent meeting EU Ecolabel standards — which laboratory testing beforehand had already shown to clean noticeably less effectively, with lower whiteness and freshness, removing fewer stains in 12 of 14 standard test stains compared with the high-performance product.

Participants did not know which product they were using (a blinded design), to prevent expectations from biasing how they rated or used the detergent. Throughout the study, participants logged a short diary after every wash — recording temperature, cycle length, machine fill level, how soiled the load was, how much detergent they used, whether they used any additional products (fabric softener, stain removers, etc.), and how satisfied they were. They also completed more detailed surveys at weeks 4, 8, and 12, and a subset took part in in-depth interviews to help explain the reasoning behind any behavior changes.

Consumers Noticed the Performance Gap Immediately

The first clear result: participants could tell the difference in performance between the two products, even without knowing their brand or identity. Overall satisfaction with the eco-brand product declined noticeably over the course of the study, particularly for attributes like stain removal and whiteness, and even more sharply for scent — the sense of clothes being "clean and fresh-smelling."

This drop in satisfaction carried other consequences as well: participants using the eco-brand product said they were less likely to buy it again if it were sold commercially, and reported lower trust in the product, less pride in their laundry results, and less confidence that they would get the results they wanted — compared with participants using the high-performance product.

Two Compensatory Behaviors

The most notable part of the study is how consumers responded to that drop in performance. Diary data revealed two behaviors that changed significantly between the two groups, while other factors — machine fill level, soil level, cycle length, and use of additional products — showed no meaningful difference.

Increased detergent dosing. This was the most common compensatory behavior observed. While dosing in the control group stayed fairly stable across the eight weeks (after an initial uptick, likely because participants were receiving free product), dosing among the eco-brand group rose steadily throughout the study with no sign of leveling off — reaching a difference equivalent to roughly one extra tablet for every five washes by the later weeks. In interviews, several participants said they increased their dose because they worried their clothes weren't clean or fresh enough, and that using two tablets instead of one gave them more confidence in the result, regardless of what they were washing.

Higher wash temperatures. The temperature gap between the two groups also widened over time — from about 0.6°C in the first four weeks to roughly 1.1–1.5°C by the later weeks, with the eco-brand group washing at higher temperatures. That gap matters environmentally: industry estimates suggest that if everyone in Europe lowered their wash temperature by just 1°C, it would cut carbon emissions by roughly 350,000 tons a year. Interestingly, both groups washed a similar proportion of cold loads (30°C or below) during the first half of the study, but in the second half the control group kept increasing its share of cold washes while the eco-brand group's share stayed flat.

Follow-up interviews suggested that many participants make temperature decisions almost on "autopilot" — based on fabric type or purpose (for example, washing underwear or bedding hot to sanitize) rather than deliberate choice each time. Some participants who were unhappy with the eco-brand product's performance in cold washes chose not to raise the temperature at all, instead reaching for an extra stain remover — a workaround they themselves were not entirely happy with, since it meant relying on an additional product they hadn't intended to use.

Why This Matters for Emissions Goals

According to the researchers, these findings point to a real paradox in the laundry industry's sustainability strategy: cutting a detergent's ingredient footprint to reduce its own environmental impact can backfire if it pushes consumers to compensate by washing more and washing hotter. Earlier life-cycle analyses have shown that a detergent's chemical ingredients account for only a small share of the laundry process's total environmental impact — most of it comes from the energy used to heat water. In other words, if consumers end up using twice as much detergent and washing at higher temperatures, the overall environmental impact — including the added manufacturing, packaging, and shipping involved in producing more detergent — could offset or even outweigh the benefit of a "greener" formulation.

The researchers suggest a more effective approach may be developing detergents that combine strong cleaning performance with good results at low temperatures — encouraging consumers to adopt cold-water washing voluntarily and consistently, because they trust the outcome, rather than focusing solely on cutting ingredients at the cost of performance.

Limitations

The authors note that this study was conducted only in France, so further research is needed to confirm whether these findings hold across the broader European population. They also suggest that future studies should run over longer periods to see whether the behavioral gap between the two groups continues to widen over time, and should use formal life-cycle analysis (LCA) to quantify the overall environmental trade-off between using a high-performance detergent at lower doses and temperatures versus using an eco-brand product that ends up requiring higher doses and temperatures to compensate.

Source: Cortez, D.M., Ter Bekke, M., Liang, Z. & Stamminger, R. "The impact of detergent performance on sustainable consumer laundry behavior: a socio-technical challenge," Tenside, Surfactants, Detergents 61(3), 203–215 (2024). DOI: 10.1515/tsd-2023-2575. Published Open Access under a Creative Commons Attribution 4.0 license.