Underwear, T-shirts and other white cottons are often washed in hot water because hot water is capable of killing bacteria as well as getting very soiled fabrics clean. White clothing items, linens and other items that can be washed in hot water can also be dried on the hottest dryer setting, usually a regular load at the heavy-high or cottons setting. White easy-care or permanent-press items are washed in cooler water and also dried at a lower setting, such as medium and permanent press. When in doubt, follow the label instructions.
If you need to wash both cottons and easy-care or permanent press white items, you have two choices. One option is to separate the pile into cottons and easy-care items and then wash and dry them accordingly, as two smaller, separate loads. Alternatively, you can wash cotton and easy-care white items together in a single load and also dry them together, which conserves both water and energy. It’s safe to wash and dry cottons and permanent press items together as long as you choose the lower temperature settings.
Drying a mixed load -- both permanent press and regular cottons together -- at the lower easy care setting means that the various laundry items will dry at different times, permanent press finishing first. Anticipate this and set your timer accordingly. Remove the easy-care items as soon as they are dry. Continue drying the remaining cotton items for 10 to 15 more minutes -- now at the cotton setting -- and remove them as soon as they are dry. Over drying fabrics increases wear and tear and can cause shrinkage.
Take your whites out of the dryer as soon as they are dry to prevent fabric wear and tear, shrinkage and unwanted wrinkles. The process of getting the timing tight is more art than science. If your laundry overcooks or stays in the dryer until it cools and gets thoroughly wrinkled, an easy fix is to toss in a clean, somewhat wet washcloth and run the dryer for an extra 15 to 20 minutes to re-dry it and remove the wrinkles.