There isn’t a specific temperature that clothes shrink at in the washing machine or tumble dryer. Natural fibres such as wool can shrink even at cold temperatures of 30 degrees Celsius, whereas synthetic fibres should not shrink at all unless exposed to temperatures of at least 90 degrees Celsius.
Temperature isn’t the only thing that shrinks clothes. Agitation from the washing machine or dryer also contributes to shrinking, so whether or not your clothes will shrink can depend on how much they are agitated as well as the temperature.
Do Specific Temperatures Shrink Clothes?
40 degrees Celsius
Machine washing at 40 degrees Celsius is likely to shrink natural fibres such as cotton, wool and silk, unless they have been pre-shrunk. Once cotton clothes have been shrunk the first time, they will not shrink much in subsequent washes.
Synthetic fibres such as nylon and polyester should not shrink at 40 degrees Celsius.
50 degrees Celsius
50 degrees Celsius will give similar results to 40 degrees Celsius. Natural fibres like cotton, silk and wool are likely to shrink, whereas synthetic fibres won’t shrink.
60 degrees Celsius
60 degrees Celsius is a hot wash. Washing at this temperature increases the risk of shrinkage. Natural fibres like wool are likely to shrink even more at this temperature than they would at low temperatures. However, synthetic fibres such as nylon still shouldn’t shrink.
Tumble dryers can reach maximum temperatures of 70-75 °C, so tumble drying natural fibres is likely to shrink them as well.
90 degrees Celsius
90 degrees Celsius is a very hot wash. This temperature could shrink any kind of fabric, even synthetics.
Can Clothes Shrink at Cold Temperatures?
Yes, clothes made from natural fibres such as wool can shrink even at cold temperatures. This is because heat isn’t the only thing that contributes to shrinkage—they can also shrink from being agitated.
Agitation from the washing machine or moving the item of clothing around while hand washing can cause felting in natural fibres such as wool. This means that the protein scales on wool bind interlock with each other, pulling them closer together and shrinking the garment.
What Causes Clothes to Shrink?
There are three main reasons clothes shrink in the wash:
1. Felting shrinkage (heat and agitation)
This affects animal fibres such as wool. Hot water and agitation makes the scales on these fibres open and bind together, causing shrinkage.
2. Relaxation shrinkage (water)
Clothes made from cotton, silk and linen soak up water when they are washed. This releases tension from the fabric causing clothes to shrink.
3. Consolidation shrinkage (heat, water and agitation)
This type of shrinkage occurs when heat, water and agitation combine to release the tension from fibres, causing them to shrink. Fabrics are made tense during the manufacturing process. Consolidation reverses this, returning the fabrics to their original, smaller state.
How to Avoid Shrinking Clothes
Here are some tips to avoid shrinking clothes.
- Follow the care label carefully. It should tell you what temperature to wash the item at, and whether or not it can be tumble dried.
- When in doubt, use cool temperatures.
- Be extra careful with wool and silk. Hand wash them by letting them soak in water rather than putting them in the tumble dryer.
- Dry on a clothes airer or washing line rather than using the dryer.
- Use the gentle cycle on your washing machine.
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