T-shirts are generally made from cotton because of its many positive qualities. Cotton is inexpensive, it is a natural fiber that breathes well and allows moisture to escape instead of stay on the skin. It is also incredibly soft to the touch. Many consider it to be the most comfortable fabric in the world. The use of cotton in t-shirts, however, means that they will shrink slightly if there is a high percentage of cotton in the shirt.
Cotton shrinks when it is exposed to heat for any length of time. The way that many people wash their clothes will usually expose the clothing to a great deal of heat. The clothes are often washed in warm or hot water, exposing t-shirts and other items to hot water for a prolonged period of time. When washing t-shirts, they can be kept from shrinking during the washing stage by washing them in cold water instead.
The second part of the laundry cycle, drying the clothes, is another source of heat exposure. The heat from dryer cycles is what causes a great deal of cotton shrinkage. This happens because the heat of a dryer is intense and prolonged. A complete dryer cycle may take an hour or longer, exposing the t-shirt and other items to a very long period of heat. This can be avoided if needed by using a different dryer cycle. Most dryers have a tumble dry cycle that dries clothes without heat. The tumble dry setting does just what the name implies- it tumbles the clothes over and over again, keeping them moving through the air in the dryer. This dries the clothes without the use of heat, though it may take longer for the clothing to become thoroughly dry.
There are other occasions when a t-shirt can become hot while not being washed or dried. There are many people who wear a t-shirt swimming or doing other outdoor activities that cause the shirt to become wet. This can include washing the car, watering plants, etc. Staying outdoors to warm yourself in the sun is a quick way to dry off, but it can also cause the t-shirt to heat up, causing it to shrink. To avoid this type of shrinkage, go indoors when you want to dry the shirt. It can be taken off and placed on a flat surface to dry. This will keep it cool and avoid any heat that will shrink it.
Line drying clothes is a good way to cut down on electricity and to give clothes a fresh, natural smell. However, line drying clothes on a hot day can also cause cotton clothing to shrink. The heat from the sun will act on the water in the shirt, heating it up and causing the natural shrinking of cotton. To avoid this reaction, laundry can be dried indoors in a bathroom. Simply hang the clothing over a shower curtain rod or lay the items flat in a bathtub. Or, wait for cool, overcast days to line-dry the shirt.