After taking off a sweater, do you put it straight into the laundry basket, or check its smell and dirt before wearing it again? A study of Nordic consumers found that wool garments were used longer between washes than similar cotton garments. For wool, decisions also appeared to depend on the garment’s current condition rather than a fixed rule to wash it after wearing.
Published in 2016, the paper examined not only washing frequency but also temperature, detergent, drying, and concerns about care. Its aim was to consider wool’s properties alongside actual everyday habits and explore opportunities to reduce the environmental burden of clothing care.
Two questionnaires and interviews with 30 people
The researchers used Norwegian survey A, with 1,124 respondents, and survey B, with 546. Survey A was weighted to reflect the population’s composition. Survey B recruited through several channels and included disproportionately many women and highly educated people, so it was not treated as nationally representative.
From 131 people recruited separately, they also selected 30 for interviews to capture varied experiences with wool and other characteristics. Fifteen were from Norway and fifteen from Sweden; 25 were women and five were men. The interviews followed selected themes while allowing conversation to develop, addressing everyday garments as well as views on wool underwear and bedding.
The new data concerned consumers’ reported habits and perceptions. Later in the paper, these were compared with existing experimental research on textiles and laundering. The study did not measure odor components or bacterial counts on participants’ clothes, so reported lengths of wear should be read as measures of real-life decisions.
Wool sweaters were used longer between washes than cotton sweaters
In survey A, the mean number of uses between washes was 8.9 for wool sweaters and 4.7 for cotton sweaters. Wool underwear averaged 3.9 uses and cotton T-shirts 2.8, again indicating longer use for wool.
The original table labels these values as “days,” but the questionnaire in the appendix asks how many times the garments are used. They are therefore best understood as responses about wear between washes, not exact durations such as wearing a sweater for 8.9 consecutive days. Survey A also excluded extreme responses of 100 or more, and median sweater values were 5 for wool and 3 for cotton. The means alone do not describe everyone’s habits.
Many respondents reported washing cotton T-shirts, underwear, and synthetic sportswear after few wears, whereas practices for wool varied more widely. Interviewees also described context-dependent decisions, such as washing immediately after sweaty exercise but reusing garments worn only briefly for commuting.
Checking odor and refreshing clothes by airing
In survey B, airing to refresh garments was more common for wool than for other materials. Interviews included examples of reusing sweat-exposed clothing in places where washing was difficult, such as mountain cabins, by spreading it out to dry rather than leaving it piled up.
Interestingly, some people knew about these methods without making full use of them in everyday life. Some believed they needed an outdoor airing space, while others remained unsure about cleanliness even when odor was not a concern. Living space and reassurance can therefore stand between knowing a material’s properties and changing daily care habits.
The authors cited previous findings that airing reduces sweat odor in wool and discussed replacing some washing with spot cleaning or airing. What the present survey directly revealed was a gap between understanding these methods and practicing them. How low odor, visible dirt, and microbial cleanliness relate remains a question for further research.
Low-temperature washing does not always provide reassurance
In survey B, wool garments were washed at lower temperatures than similar cotton garments, often at 30°C. In survey A, 70% mainly machine-washed wool and 19% hand-washed it. At least in this Norwegian survey, wool care did not rely solely on hand washing.
For underwear and bedding, however, concern about whether low temperatures could achieve adequate cleanliness was prominent. Norwegian interviewees described dedicated detergent and wool programs as a common procedure, while some Swedish interviewees did not know about or own dedicated detergent. These differences are qualitative findings from the selected groups of fifteen people each.
In addition, 73% of survey B respondents washed wool separately. When people own only a few wool garments, accumulating a load can be difficult, leaving them to wait longer or wash a small load. There were also complaints about stain removal. Difficulties with wool thus involved not only the fiber itself, but also laundry sorting and the number of garments owned.
Frequent shrinkage was reported by 7.7% in survey A. Although people without shrinkage problems were more likely to use a washing machine, this alone does not establish hand washing as the cause of shrinkage. People may have switched to hand washing after garments shrank, and garment differences such as shrink-resistant treatments could also matter.
Consider consumers’ practices alongside machine and detergent development
The discussion does not stop at asking consumers to wash less often. It also identifies technical challenges: wool detergents and programs that deliver convincing stain removal, spinning that shortens drying without damaging garments, and systems that make small quantities of wool easier to handle.
For example, the authors cite earlier findings that higher spin speeds reduce residual moisture, while explaining that acceleration and deceleration matter as well as speed because wet fibers can shrink when movement causes them to interlock. Discussion of high-temperature treatment and washing mixed materials also concerns development possibilities based on limited earlier tests. It does not provide a universal procedure for overriding individual garments’ care labels.
Nor did this study perform a new life-cycle assessment calculating the total environmental burden of wool products. It shows the need to consider materials, machines, knowledge, and habits together when understanding actual washing frequency and temperature and reducing care-related impacts.
Summary
In the Norwegian surveys, wool sweaters and underwear were used longer between washes and washed at lower temperatures than similar cotton garments. Wool care included checking the garment’s condition after wear and airing, while concerns about cleanliness, dissatisfaction with stain removal, and the inconvenience of separately washing small loads also emerged.
The study shows that washing frequency is not automatically determined by odor and dirt alone. Experience with a material, confidence in its cleanliness, and the convenience of washing machines all help shape when the next wash occurs. Opportunities to reduce environmental impacts lie in both these everyday judgments and the technology supporting garment care.
At publication, both authors were affiliated with the Norwegian consumer research institute SIFO. No separate research-funding or competing-interest statement was found in the original paper examined.
Reference
Laitala, K., & Klepp, I. G. (2016). Wool Wash: Technical Performance and Consumer Habits. Tenside Surfactants Detergents, 53(5), 458–469. Original paper / Author-shared full text
