Both gas-powered and electric clothes dryers employ electric motors that cause the drum to spin during the drying cycle. Gas-powered models, however, use natural gas to heat the air that dries the clothes. Dryers powered fully by electricity make use of heating elements to heat the air. They both direct the heated air into the tumbling drum via a duct.
An automatic "cool-down" period---a timed interval at the end of the drying cycle--- helps prevent wrinkling. Another feature, called "after-cycle tumbling," uses periodic tumbling to help prevent wrinkles in clothes. A "tumble press" process can be used to remove wrinkles from clean, dry clothes. Some automatic dryers provide a signal when the drying cycle is over to prompt the removal of clothes before wrinkling occurs.
Automatic dryers have features that increase the efficiency of the process of drying clothes. This is accomplished in part by controlling the amount of time the drying cycle takes and by controlling the temperature of the air used for drying. User controls allow selecting drying time and temperature; top line models use electronic controls. Some modern automatic dryers can even provide an alert when the lint filter needs cleaning.
An interlock, or door switch, prevents the dryer from starting until the door is securely closed. Another feature starts a blower fan when drying is initiated. The blower fan starts prior to the heating element (or burner in gas models) is employed. This prevents dangerous heat buildup that can lead to a fire. A thermostatically controlled temperature system regulates the temperature in the drum, preventing scorched clothes and possible fires.
Electric automatic clothes dryers may be up to $100 less expensive than gas-powered models. However, gas models are cheaper and more efficient to operate over the long term. Consumer Reports tests indicate there is little performance difference between gas and electric versions of the same dryer. Experts recommend the "moisture sensor" feature in an automatic dryer because it not only saves energy but also prolongs the life of clothing. This feature is available on lower-priced automatic dryers.
