Clothes shrink when certain fibers change structure because of heat, water, agitation, or tension released during washing and drying. Cotton, wool, and blended fabrics behave differently, so the care label matters more than any universal temperature rule.
Heat accelerates shrinkage in many fibers
Hot water and high dryer heat can release manufacturing tension or compact fibers. If a garment allows cool or warm washing and low drying heat, those settings generally reduce dimensional change compared with hotter cycles.
Wool can felt from agitation and temperature
Fiber scales can lock together when heat, moisture, and agitation are combined. A wool cycle or hand wash according to the label reduces that friction; stretching afterward does not reliably reverse felting.
The dryer often adds more heat than the washer
A garment that survived washing without change can still shrink in a high-heat or overly long drying cycle. Remove it when dry and use air or low heat when the care label calls for it.
Some shrinkage can be permanent
Some garments regain a little shape when dampened and gently reshaped, but felted fibers or heat-distorted material may not return to their original size. Avoid stressing seams and check the care label before attempting stretching treatments.
Sources
- American Cleaning Institute — Cleaning Tips — General household-cleaning practices and responsible product use.