What is the Difference Between Air Purifier and Humidifier?

Both air purifiers and humidifiers have their own function when it comes to improving air quality, but what sets them apart? To help you decide which one you might need, we will explain the differences between the two.

Since they have entirely different functions, both can be used simultaneously. But, before we dive deeper, let’s take a glance at their purpose:

Air purifiers:

  • Remove dust and allergens
  • Reduce mold and germs
  • Eliminate bad odors
  • Should run constantly


  • Control air humidity
  • Help with congestion
  • Moisturize skin
  • Shouldn’t run constantly

Now that we can distinguish the two, let’s take a better look at how they work.

Air Purifier

The purpose of these devices is to remove the airborne contaminants from the air indoors. They do so by trapping or neutralizing allergens, dust, mold, pet dander, bacteria, and viruses, etc.

Air purifiers are also very efficient in removing smoke. Should you find yourself looking to eliminate smoke in your room, car, or workplace, check out our reviews of the best air purifiers for cigarette smoke.

They use different techniques but are mainly based on air filters. The most common one is the true HEPA filter, whose build tends to vary from device to device. The HEPA filter is up to 99.97% effective at airborne contaminant elimination, depending on its quality. Some air purifiers also might include ionizers or ozonators, which produce negative ions and safe amounts of ozone respectively – all towards the same goal: fewer pollutants and better air quality.

Thus, air purifiers are meant only to reduce the number of harmful particles in the air and don’t control air humidity.


The main function of a humidifier is to add moisture to the air in an enclosed space. The recommended air humidity levels indoors are between 30% and 50%. Added air moisture can help with conditions such as asthma, improve skin texture, and relieve respiratory irritations.

To keep the air moisture at an ideal level, humidifiers discharge water vapor in the air when necessary. Though, if you keep them on for too long, they can overly increase air humidity and cause issues such as increased mold and mildew growth and enhanced dust mite reproduction.

In order to keep a humidifier running, you’d need to add and replace the water in the device. To keep them running at maximum efficiency you’d also need to clean them regularly. In some instances, the use of demineralized or distilled water might be better than ordinary water, but that depends on the humidifier type.

The two most common types of humidifiers are ultrasonic humidifiers and evaporative humidifiers. The ultrasonic ones use vibrating metal or ceramic plates to create water vapor, while evaporative humidifiers use a wick filter that absorbs water from the tank, which is then pumped out in the room in a gaseous state.


We hope that you found this article informative and that you now have the knowledge to make an informed decision about what kind of device would work best for you.

If we piqued your interest in air quality and how to improve it, make sure to check the other articles available on our blog.