The hair dryer that can be used in university dormitory is generally below 300W W. According to the regulations of the school, you should pay attention to safety when using it.
The hair dryer is a combination of a set of electric heating wires and a high-speed small electric fan. When electrified, the heating wire will generate heat, and the wind from the electric fan will turn into hot air after passing through the heating wire. If only the small electric fan rotates and the heating wire is not hot, then the wind will blow out, not hot.