Although not all reviewers agree on their effectiveness, dryer balls work to separate clothes while they tumble, promoting continuous air exchange and hastening drying time. Manufacturers claim that dryer balls also reduce static and soften fabric, substituting for chemical-based fabric softeners.
The theory behind the use of dryer balls is that the balls protect laundry against clumping in a dryer. This makes the laundry dry more efficiently. Moreover, the balls retain heat, which they pass along, boosting the drying process.
Opinion is evenly divided on whether dryer balls actually work. MakesMomHappy.com states that the balls work, although they do not eliminate static as reported, while About.com holds that the balls reduce drying time and soften clothes. On Amazon.com, some buyers are very impressed while an equal number say they never work.
Some reviewers theorize that the reason dryer balls seem to work for some people and not others is due to the type of fabric dried, with dryer balls working well on some fabrics and not others. Load size may also affect the balls' performance. For example, dryer balls may have less of an effect on small loads of socks and underwear than on a blanket or other large item.