Washing underwear: 30, 40 or 60 °C? How to choose the right temperature

Underwear used to go straight into the boil wash. Today the dial usually sits at 30 or 40 °C, and many people wonder whether that is really clean enough. When washing underwear, the right temperature depends on three things: the fabric, the detergent and whether anyone in the household is ill.

The good news: for healthy people and everyday laundry, 60 °C is rarely needed. Five rules show when to choose 30, 40 or 60 degrees, what lace and microfibre can take, and why laundry sanitisers are usually unnecessary.

Why temperature matters when washing underwear

Underwear sits directly against the skin. It absorbs sweat, skin flakes and bodily secretions – and with them bacteria and fungi. Whether they disappear in the wash does not depend on heat alone. The detergent, enough water in the drum and complete drying are just as important.

Washing too hot comes at a price, though: elastane loses its stretch, lace turns rough, colours fade and microfibre loses its smooth surface. If you wash everything at 60 degrees, you will replace your underwear sooner than necessary. Then there is the electricity: every extra degree uses energy.

1. Read the care label

The number in the wash tub on the label is the maximum permitted temperature, not the recommended one. One bar underneath means a gentle cycle, two bars a very gentle one. The GINETEX care symbols index, run by the organisation behind the symbols, explains what each one means in practice. It also notes that hand washing means 40 °C at most, without rubbing or wringing.

For a full overview, see our guide to understanding laundry symbols. If a pair of knickers says 30 °C only, stick to it – even if you would prefer a hotter wash.

2. Everyday laundry: 40 °C with a good detergent

For the underwear of healthy adults, a 40-degree programme is usually enough. The detergent makes the difference: a heavy-duty powder detergent usually contains oxygen-based bleach, which works well against bacteria and odours even at medium temperatures. For coloured items, use a colour detergent and wash whites and colours separately.

Lower temperatures save energy. EnergieSchweiz, the Swiss federal energy programme, recommends washing at 20 to 30 °C where possible, on eco programmes and with a full drum – and not increasing the detergent dose at low temperatures. In practice: wash delicate items cool, everyday cotton at 40 degrees and go hotter only when needed.

3. During illness: 60 °C for washable cotton

Things are different when someone in the household is ill. With stomach bugs, fungal infections of the skin or intimate area, or when someone is being cared for at home, wash underwear, pyjamas and towels at 60 °C – provided the label allows it. Wash this laundry separately and do not overfill the drum.

The Federal Office of Public Health (FOPH) describes norovirus as highly infectious and spread via hands and contaminated objects; thorough hand washing with soap is the most important measure. Wear gloves when loading soiled laundry, or wash your hands straight afterwards.

4. Wash lace, microfibre and shapewear gently

Fine lingerie likes it cool and calm. Wash lace briefs, bodysuits and microfibre pieces at 30 °C on a delicates or hand-wash cycle, ideally in a mesh laundry bag. Fasten hooks so nothing snags, and fill the drum only halfway. A delicates detergent without bleach protects colours and fibres.

Bras have their own rules because of underwires and cups – see our guide on how to wash a bra. Period pants also need special treatment: rinse them in cold water before washing; details are in our article on washing period underwear.

Skip fabric softener for sports and technical underwear. It coats the fibres and can reduce their ability to wick moisture away.

5. Dry thoroughly and question laundry sanitisers

After washing, hang underwear on the line or airer straight away, spread out well rather than on top of each other. Cotton can go in the tumble dryer if the label allows; lace, elastane and shapewear are better air-dried, as heat ages the material.

Laundry sanitisers promise germ-free laundry even at low temperatures. In an ordinary household of healthy people, however, they are rarely needed: a suitable detergent, the right temperature and complete drying are enough. Their active ingredients burden wastewater and can irritate sensitive skin. A regular hot maintenance wash for the machine itself is more useful – our guide on cleaning the washing machine shows how.

Common mistakes when washing underwear

• Everything at 60 degrees: damages elastane and lace and, for healthy people, adds little hygiene compared with 40 °C and a good detergent.
• Colour detergent for white cotton: without bleach, whites turn grey over time and hold on to odours more easily.
• An overfilled drum: the laundry is not rinsed properly and detergent residue stays in the fabric.
• Damp laundry in the basket: underwear left damp for hours starts to smell before it has even been washed.

Priority Clean editorial teamOur cleaning team from Alberswil, Canton of Lucerne, shares hands-on experience from move-out, house, office and window cleaning across Central and Northwestern Switzerland.