Other variables can influence drying besides the temperature. You could also consider the amount of moisture or dampness in the clothes, the size of the load to be dried and even the steady flow or path of the hot air in the appliance. These variables are easy to fix. You can avoid overloading the drum and making sure you periodically clean the lint filter. However, even after remedying everything else, the internal temperature of the dryer is still an overarching factor. Most people's simple solution to this remaining variable is to determine and use the maximum drying temperature available. However, the basics of temperature become increasingly complex based on the design and features of your dryer.
Dryers that use Energy Star's "Energy Guide" might have lower maximum temperatures.
After the early 1990s, some dryer manufacturers actually reduced the internal temperature. Modern dryers have at least three general cycles: low heat for delicates, medium heat for permanent press and high heat for regular clothes. The temperature range is 125 to 135 F across these cycles. As a reference, the U.S. Consumer Product Safety Commission states that an adult can suffer third-degree burns after five minutes, if his skin is exposed to hot tap water at 120 F. Obviously, for your safety, companies want to make sure that the dryer cannot cause harm as you are interrupting a cycle or unloading clothes after drying is complete.
Some dryer brands and models can reach as high as 176 F. These extreme temperatures might be common in commercial and professional grade dryers that are used in large households, uniform cleaning services and laundromats. To reach these scorching temperatures, the heating element itself might need to top out at 210 F (water boils at 212 F). The maximum temperature on the inside of the drum in your dryer is relative to the heating element that lies on the outside of the drum. That's why you should be careful about touching the metallic walls and casing of the dryer during and after it has been through a cycle.
Many high-tech appliances can automatically sense the temperature — and the moisture level — in a load of clothes. This is akin to the temperature probe that you place in meat and poultry while cooking in your oven. So measuring moisture levels is a variable that can automatically affect the maximum temperature of the dryer.
Leaving the clothes in the tumbler too long can create wrinkles. Dryer manufacturers conceived of these temperature and moisture sensors to reduce wrinkling — potentially minimizing your ironing chores. The "Steam Cycle," as it is sometimes labeled, will spray water through a nozzle into the tumbling drum after it is heated, and the contact with the hot air produces steam.
Another way to think about maximum temperature is the dryer's ability to completely and utterly eliminate harmful organisms from your garments. Typically, the scalding hot water in the washing machine kills germs and bacteria long before you transition to the dryer. However, there are some materials, such as feathers, that are too delicate to go in the washer, no matter how minimally the tumbler agitates. Dryer manufacturers use sanitation standards put forth by the National Science Foundation, and the goal is to kill 99.9 percent of the bacteria using high temperature heat. Consult your user's manual on how to properly use this alternative drying method.