How Hair Dryer Works?

how hair dryer works

Hairdryers were invented in the 19th Century. They first appeared in 1920. Now millions of people are using hair dryers on daily basis. Although hair dry at their own time but some folks want quick dryness and this is where they use a hairdryer, especially in winters. A hairdryer is manufactured to provide normal or hot air for wet & damp hair.

Therefore, this electromechanical device will evaporate the water from the hair. Basic models hold two switches, one for turning on and the other for turning off. Another switch is also given to speed up the fan or for controlling airflow. Some high-end models have one more switch to regulate the temperature.

The Working Principle

The hairdryer or blow dryer works on the principle of evaporation and humidity. The evaporation is controlled by relative humidity. For instance, if the humidity is 90% then it means that air is holding 90% of its maximum water volume. Heated air reduces the relative humidity as it has the same volume of water but it can hold more water. Lower relative humidity will result in more water evaporation. So, according to this principle, hot air will make your hair dry quickly by evaporating water faster

How Hair Dryer Work?

how hair dryer work

Heating elements & electric fans combine and make a hairdryer. A resistor named nichrome wire is used in the making of the heating element. This resistor plays its role by resisting the electric flow, which is then turned into heat energy. The hairdryer works on passing the air blows resistor & absorbing heat while passing.

Electric hair dryers use room temperature in the air blowing by its vents. Then the air passes through the nichrome wire, where it is heated. That makes the air hot for hair drying. This process of air blowing fastens the water evaporation. When power is applied then it spins the hairdryer motor fastly which results in faster inside fan speed. This is the point where air draws through small holes on the dryer sides.

In simple words, hairdryers utilize their heating element & motor-driven fan to convert electric energy into heat energy. The whole process is mentioned below in point for better understanding.

  • Current flows in a hairdryer when turning on.
  • Then it flows towards the heating element.
  • Electric motor starts to spin that turns on the inside fan.
  • The generated airflow is directed toward the hairdryer barrel, after passing through the heating element.
  • The air gets hot after passing from the heating element. Here it’s get converted into heat energy from electric energy.
  • The hot hair starts getting out of the barrel.

How Hairdryer Makes Flow?

how hair dryer makes flow

Sometimes we feel a strong thrust of airflow from a small hairdryer model. Here we are going to discuss how a hairdryer makes a strong flow with a small fan? It uses a water wheel (hydraulic turbine). The hairdryer fan consumes electrical energy to develop airflow. Whereas, water wheel generates energy from flowing water.

The small inside fan is attached to the tip of the motor that starts spinning when you turn on the supply. It starts a centrifugal movement with the help of spinning fan blades, which are drawn through small air inlets inside the hairdryer body. These are covered in a safety screen that restricts the sucking of other objects like hair strands etc. Then the air moves towards the downside of the hairdryer barrel.

Many hair dryers have combo settings of low & high airflow. You will also find this written on product boxes. This function involves speed modulating at which the motor is spinning. It is achieved by changing the current flow through the circuit feeding motor part. With the low supply power, the fan movement will also low and it pushes less air from the hairdryer and vice versa.

Coming towards the latest hair dryers, they produce hot air ions in the shape of charged particles. This is an advanced step from only producing hot air hair dryers. This new mechanism helps in getting quick, shiny, smooth, and silky hair. Besides, it also makes hair static by making them less prone to dust & dirt.

Heating a Hair Dryer

Most of the hairdryers use a nichrome wire heating element, which is wrapped around mica insulating boards. It is composed of two materials chromium and nickel. The majority of the household products use this material as a heating element. For example curlers and toasters etc. Features of nichrome are given below that makes it the best heating element.

  • When heated, it doesn’t get oxidized. Some other products like iron rust get heat bit faster when temperature arises similar to hairdryer & toasters.
  • Nichrome is a poor conductor of electricity as compared to copper. Due to this quality, it provides enough resistance to the alloy to get properly hot from the flowing current.
  • Fan generated airflow is pushed towards the heating element. While entering the air is pretty much cool as compared to nichrome wire. Therefore, the heat flows into the air from the wire. But when the air is pushed by the fan and convection, it becomes hot and this cycle goes on

Hot Air Mechanism

  • The heating element & power is directly related to each other. More power will generate more heat. Now advanced dryers can produce heat at about 2000 watts whereas, in the early time, it was limited to 100 watts only. Dryers producing high heath at low settings vary the power supply to manage the airflow temperature.
  • The traveling time of air inside the dryer barrel and get heated by the nichrome is limited up to two seconds. This is done to prevent the temperature from reaching a high level.

You may have observed a ceramic coating on the heating element of dryers. It comes in different contours, depending on model specifications. This coating is said to be better because it distributes effectively & even heats. Moreover, it makes the best compatibility with perfect heat flow and ions creation


Here we will discuss some safety features that are mandatory for avoiding any functioning error or misuse.

  • Overheating may burn your scalp if the temperature arises up to 60 degrees Celsius. The heat sensor may trip with the rising temperature. The motor will shut down at the same time. Hairdryers have safety switches for this purpose. Mostly hair dryers use a bi-metallic strip as a cutoff switch.
  • The bi-metallic strip is composed of two metals that expand on heating. The strip bends on heating up because one metal became larger than the other. On reaching a certain point it trips the power supplying switch.
  • Proper insulation is also done for protecting the hairdryer from outside. Without insulation, the outside gets too much heat that can burn your hand on touching. For safety purposes, heat insulation is provided.
  • Thermal fuse presence is also provided that protects against catching fire or overheating. It will be blown up and break the circuit when the hairdryer gets overheated. The thermal fuse is included in the heating element.
  • The hairdryer barrel is covered with the front grill. This grill is made up of a heat resistant material that provides safety. It makes the barrel end away from heat.

Leave a Comment

Your email address will not be published. Required fields are marked *