The obvious reason why we don’t want to tumble dry our clothes is the negative environmental impact. There are other reasons why you may want to think about putting your washing line back up though.
Firstly, as we already know, dryers shrink clothing. A recent study confirmed that dryers shrink clothing twice as much as washing alone. The study says that the temperature of the tumble dryer is not related to the degree of shrinkage — it is the agitation and forced air that changes the size of the fabric.
The agitation of tumble drying also produces microscopic wear to clothing - you can see this just by looking at the filter in your dryer. There you will find tiny pieces of fabric that have been worn off your clothes during drying - this reduces the longevity of garments. The study found that towels washed and dried 20 times lost 50% of their tensile strength.
On the other hand, particularly for white garments, sunlight has benefits that your dryer can never hope to match. Sunlight bleaches beautifully - if you would like the whitest of whites then there is nothing so effective as hanging them out in the sun. Sunlight also has a strong anti-bacterial effect. UV light kills bacteria that may survive a cool wash, not only those that are potentially harmful but also those that make clothes smell.
It is strange to think that our grandparents had much whiter whites than we do!