A hairdryer is an object we use almost daily in our life. But have you ever stopped to think about how a hair dryer works? First introduced in the 1920s, this device helps evaporate water quickly from wet tresses by blowing hot or cold air over them. So it’s not a surprise that a hair dryer is also called a blow dryer sometimes.
Your hair dryer works on the principle of evaporation and relative humidity. Confused? It’s simple really. Relative humidity is the number of water particles or moisture that is present in the air.
When the air around us is heated, it can hold a larger percentage of water vapor (this is why those hot summer months feel so claustrophobic and sticky). And as it can hold more moisture, water tends to evaporate faster.
But what has this got to do with your hair dryer? It helps heat the air surrounding the wet strands of your tresses. So its capacity to hold moisture increases, and therefore, the water from your hair evaporates quickly.
How a hair dryer works
Before we get to a detailed guide on how a blow dryer works on hair, we need to understand what this device contains.
Hair dryer parts and function
In theory, several large and small parts go into the making of a hair dryer. But the two most important ones are the heating component and the fan.
In most hair dryers, the heating element is the nichrome wire. Nichrome is an alloy (a mixture of two metals) of nickel and chromium. Now, this heating element has the most crucial job of heating up the air inside the dryer.
It functions as a resistor or a device that converts electrical energy to heat energy. Even a few years ago, hair dryers contained copper wires. But Nichrome is a much better material, not to mention much safer.
This alloy doesn’t conduct electricity very well, which means all the energy passing through the dryer is used up to heat up the air.
Nichrome is safe from oxidization too. If you use another material like iron for the resistor, it’s prone to rusting at high temperatures. But you don’t have to worry about that with Nichrome.
The next most important part of a hair dryer is the electric fan. This fan mostly looks like one of the water turbines used to generate electricity, but smaller. Most dryers use a simple, motor-based model, and frankly, that’s enough.
When you switch on your hair dryer, the electricity helps move the motor attached to the fan. This helps the fan turn and draw in air from the inlets given in the dryer. The centrifugal force helps drive the air, towards the heating elements.
Now that you know the two main components responsible for making your hair dryer work, let’s see how the process goes.
Step 1: Switching on the dryer
When you switch on the dryer, it makes electricity pass through the device. Hair dryers come with a circuit made of either coiled wire or materials like ceramic-coated tourmaline. This circuit helps pass the electricity to the resistor.
Step 2: Fan starts rotating
The electricity supplied also reached the fan at the same time. It kickstarts the motor and makes the fan spin. There is a lot of centrifugal force generated due to this action.
Step 3: Movement of air
This centrifugal force generated by the fan helps suck in air from the outside and pushes it towards the heating element. Hair dryers come with grills or vents to control the movement of air. There is also a safety screen in a lot of models that help prevent dust, small objects, or even your locks from getting tangled in the dryer.
Step 4: Heating
The Nichrome resistor now heats up the room temperature air around it. According to the laws of physics, hot air is lighter and rises up. And due to this simple convection, the hot air blows out through the end of your dryer and cold air (pushed by the fan) replaces it, repeating the process.
Did you know?
Ever wondered about the slow and fast setting on your blow dryer. This is accomplished by altering the current flowing through the circuit and towards the fan. At low-speed settings, lesser current flows through the fan, and therefore, it spins slowly. At higher settings, more current flows making the fan spin faster and sending out a larger blast of air.
Are hair dryers good for your hair?
The hair dryer is definitely a convenient device. But whether it’s good for your hair is another thing altogether. A simple answer to this question is that a hair dryer is good for your hair, given you use it properly and not every often.
- Hot air or heat, in general, can cause the cuticles on your hair strands to open up. This can leave your hair frizzy and damaged. But most hairdryers now come with negative ion technology to prevent this from happening.
- Another important thing to remember is to dry your tresses evenly. Some dryers in the past created heat pockets where one area of air heated up more than others. But today, blow dryers come with ceramic (or ceramic-tourmaline) circuits that ensure even heat dissipation.
- No matter how great your hair dryer is, it can hurt your tresses if you use it too much. Just like your straighteners and curling irons, it’s advisable to use hot air blow dryers only 3-4 times a week.
Did you know?
Nowadays, hair dryers come with negative ion technology. These not only dissipate heated air onto your tresses but also give out a blast of negatively-charged ions. This is done by placing a small ion generating device near the fan. Negative ions can help control frizz by preventing the build-up of static.
Types of hair dryers
Most hair dryers work in similar ways. But few modifications make them very different from one another. The most popular types of hair dryers are:
Ionic hair dryers
As we’ve discussed before, ionic hair dryers contain a negative ion generating device that helps smoothen frizz and keep your tresses silky straight. If your locks are more prone to frizz, then this is the best type of dryer for you.
Ceramic hair dryers
Ceramic hair dryers are those that contain ceramic or ceramic-coated tourmaline circuits. This material helps regulate the heat levels inside the dryer, making sure your tresses don’t get a blast of very hot air at once. It’s most useful for people with thin, limp hair looking to add volume to their tresses.
Diffuser hair dryers
To get technical, this type of blow dryer isn’t really mechanically different from others. The only difference is that the end of the dryer comes with a diffuser attachment. This wide and round nozzle helps blow out air in a larger area and prevents heat from being directed at one tiny area of your locks.
This type of dryer is the best for curly, afro hair types as those textures tend to be more brittle and coarser. Sometimes, it also comes with separators to help define your curls.
FAQs about how hair dryer works
Is it better to towel dry or use a hair dryer?
Both towel drying and hair drying are essential to get perfect-looking hair. And likewise, both can be really damaging to your tresses if not done correctly. The perfect formula is to use a microfiber towel to gently remove excess water from your hair till it’s 50-70 percent dry. And then, using a blow dryer, you can style your hair.
Who invented the hair dryer?
The first hair dryer was invented by Alexandre-Ferdinand Godefroy in 1888. But this was a stationary model and couldn’t be carried in your hands. The handheld version came out later in 1920.
Can you use a hair dryer after it gets wet?
While most hair dryers today come with Ground Fault Circuit Interrupters (GFCI) to protect against electrocution, it’s still best to discard the wet hair dryer. If you really want to salvage it, you can wait for the water inside to dry completely. But it won’t be 100 percent safe to use.
Why did my hair dryer stop working?
If your hair dryer has stopped working, check the air inlets at the back to see if any dust has gathered there. Dust particles can block the airflow and prevent the dryer from working properly.
But if your blow dryer suddenly gets switched off during use, it might be due to overheating. This happens if you’re using it for more than 10 minutes at a stretch. In this case, simply switch off the device and let it cool down for a few minutes. It should be up and running after 3-5 minutes.
What plastic is a hair dryer made of?
The plastic commonly used in the manufacturing of a hair dryer is ABS or Acrylonitrile butadiene styrene.
The idea behind this innovative device is simple, and it’s been unchanged for the past few years. Yes, hair dryers now come with more safety features such as screens, thermal fuses, insulation, and cut-off switches. But the principle of the fan moving hot air and the resistor heating it up and sending it out is largely the same.
Leah LOVES hair. So much so, she dedicated an entire website to it! One of the founders of Hair Everyday and Chief Editor, Leah enjoys reviewing all the hair products and showcasing the best. She believes her most underrated articles are her hair care tips!