Help save the planet, one laundry load at a time

Jeans-cleaning study confirms measurable downsides to washing too often

Helen Metella - 10 January 2017

If you've already broken your early 2017 promise to eat less, spend less and be less of a sloth, try this much easier pledge to help improve your world-do less laundry.

Textile scientist Rachel McQueen hopes people will embrace that challenge after hearing the results of her recently published study on the downside of washing denim jeans too often.

Her study shows that throwing jeans in the washing machine after just two days of wear, compared to after 20 days, significantly degrades the fabric. McQueen and fellow researchers found double the loss of fibre mass-four per cent instead of two per cent-in the more frequently washed jeans.

That means your jeans will wear out faster, but it also means that you are using up water and electricity needlessly, driven by habit and routine, due to a mere perception that your clothing is dirty because it's been in contact with your body, said McQueen, an associate professor in the Department of Human Ecology.

The types of easy-care clothes we now own (more synthetics instead of wools and linens), coupled with the convenience of just throwing something into an in-home washing machine, means we are accustomed to washing after just one day's wear, said McQueen.

"That's much different behaviour compared to 60 or more years go, when the laundering process was very manual and labour intensive," she said.

"In a highly populated world, where resources are scarce and energy is needed to use washing machines and dryers, we need to rethink this," she said.

While it's not news to textile scientists that fabrics break down the more they are washed, McQueen wanted a real-world study, and not a lab experiment, to make clear to consumers how they are depreciating their clothes because "people are not always driven by the environmental argument alone," she said.

Jeans were chosen because they're a commonly worn clothing globally, and are often worn for more than one day. Study participants were each given two pairs of test jeans to wear during normal daily activities over six months, with each pair being worn for 60 days. One pair was washed 30 times over the test period (every two days), the other was washed only three times (every 20 days).

Participants used their own washing machines and methods, but even with some possible variation in handling-wash cycles may have differed, front-load washers are reputed to be gentler on clothes, and some people air-dried their jeans instead of machine-drying-McQueen's results were consistent across the 52 people, aged 18 to 45, who completed the study.

That's a compelling argument for pausing before automatically tossing any item of clothing into the wash after light wear, said McQueen. Even if consumers think they'll be tired of a garment by the time it wears out, prolonging its life can delay when it's put into a landfill or an incinerator (both environmentally taxing), because if its fabric is still OK it is more likely to be passed on for others to wear.

"I hope people will start thinking more consciously about these small practices," said McQueen. "Are they doing it out of convenience or necessity? Can they alter their frame of mind and alter the bigger picture?"

The study, Reducing laundering frequency to prolong the life of denim jeans, is published in the International Journal of Consumer Studies.