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Humidifier vs. Air Purifier: What’s the Difference?

Updated on September 30, 2023
Written by
Danny Ashton
Danny is the founder of HouseFresh and has been writing about air purifiers and indoor air quality since 2010. He is our lead tester, conducting all the tests we use to evaluate air quality products. That is why you will always see his name attached to our reviews.

Our verdict

Humidifier or Air Purifier? The short answer to this question is, “It depends”. 

Air purifiers remove pollutants suspended in the air and humidifiers add moisture to the air to prevent health problems related to dry air. Think about your health issues and whether an air purifier or humidifier will help you deal with those issues.

Air Purifier or Humidifier: Which is right for you? Both air purifiers and humidifiers can impact the air inside your home, but each performs a different function along with distinctive benefits. 

The name tends to give it away. An air purifier is designed to purify the air in the home, while a humidifier adds humidity to the air.

An air purifier cleans the air, whereas a humidifier makes the air wetter.

The main elements of an air purifier are a filtration system and a fan. The fan pulls air into the unit, and although the size and power of the fan can vary from unit to unit, they all direct the air into the filtration mechanism where pollutants are trapped, and cleaner air is discharged back into the room. 

The filters used are usually pre-filters, HEPA filters and activated carbon filters. All are designed to purify contaminated air in the home but do not add any moisture to the air.

A humidifier will not clean or purify the air. It adds moisture or humidity to the air by boiling water, producing steam or water vapor and forcing it into the room. This vapor may or may not be visible depending on the type of humidifier. For the humidifier to work continuously, water must be periodically added to the reservoir to maintain the unit’s operation.

There are different types of humidifiers worth knowing about:

  • Evaporative humidifier – A reservoir stores cold water and empties it into a basin. A wicking filter is used to absorb water from the basin. It then blasts air through the wet filter with the help of a fan.
  • Ultrasonic humidifier – Generates water droplets by vibrating a metal diaphragm at an ultrasonic frequency, similar to the component in a high-frequency speaker. An ultrasonic humidifier is often quiet and emits a cool fog.
  • Steam humidifier – Also known as a vaporizer, it heats water and distributes it into the room as warm steam. This is the most basic, and hence least expensive, method of introducing moisture to the air.

Air Purifier Vs. Humidifier: Which One Do You Need?

As we stated at the beginning of this article, air purifiers and humidifiers don’t do the same job, so how do you know which one is right for you?

Here is how you can tell which device will be best based on your needs.

Use an air purifier if:Use a humidifier if:
You have allergies, are an asthma sufferer, or have a respiratory illness that worsens in contaminated air.You live in an area with a dry climate.
You have a pet and want to decrease the amount of pet dander in the air.You suffer from dry skin, eyes, or hair during the winter.
You need to reduce the amount of dust that accumulates in the home.Your sinuses get aggravated, or you have nosebleeds more often due to dry air.
Household odors from cooking, smoke, pets, or mold are becoming a problem.Dry air makes your breathing more difficult.
You want to lower the levels of VOCs present in the air in the home.Snoring becomes a serious issue because of the dry air in your home.
You would like to have better, cleaner air quality throughout the home.The humidity levels in your home are too low, causing health issues.

What Are the Benefits of an Air Purifier?

The benefits of having an air purifier are wide-ranging. Let’s explore some of them in detail. 

Benefit 1: Air purifiers can help alleviate triggers of asthma attacks

Research from Yonsei Medical Journal and the National Library of Medicine states that air purifiers can positively affect asthma patients’ health by filtering fine dust and microbes from indoor air. 

​​If you have asthma, you are at the highest risk of having an attack inside the home because this is where most triggers are found. 

Examples of asthma triggers are:

  • Dry skin cells
  • Dust
  • Carbon monoxide
  • Fresh paint
  • Household cleaners
  • Air-freshener sprays
  • Hairspray
  • Perfume

There may also be mold spores or cockroaches in the home, both triggers of an asthma attack. An air purifier will help remove most, if not all, contaminants that may cause an attack.

Benefit 2: An air purifier eliminates dust and pet dander

Allergens like dust, pet dander and tobacco smoke can all be reduced, making breathing easier and allergy sufferers may notice a decrease in their symptoms after the unit has been running for a few hours. 

According to the EPA, HEPA filters can remove at least 99.97% of airborne particles with a size of 0.3 microns (µm). This means they can remove pet dander and dust easily. We made sure to only include devices that use HEPA in our list of the best air purifiers.

Benefit 3: There will be fewer noticeable odors

Cooking smells may entice the appetite, but if they linger long after the meal is over, that could be annoying. If your home doesn’t have the necessary ventilation, an air purifier will minimize, if not completely remove, any lingering cooking smells with its activated carbon filter. 

Benefit 4: Elimination of VOCs and harmful chemicals

Volatile organic compounds (VOCs) are gases produced by certain types of equipment and materials and can include carbon dioxide and nitrogen dioxide, along with many other VOCs common in our lives today. The main way that air purifiers remove VOCs is through the use of activated charcoal filters, as these trap gasses and VOCs. 

Benefit 5: Seasonal allergies can be reduced

When pollen levels are at their highest, anyone with seasonal allergies may suffer greatly from hay fever, leading to respiratory problems. A quality air purifier can eliminate any pollen that manages to enter the home.

Benefit 6: Reduction in the spread of airborne diseases

Microscopic airborne pathogens spread airborne diseases. If one family member becomes ill with the flu, the rest of the family will also catch the flu. The reason is everyone is breathing infected air. A HEPA filter air purifier can capture bacteria and viruses, helping to reduce the chances of infection.

Benefit 7: A better night’s sleep

If you wake up a few times in the night coughing or sneezing, an air purifier can help you get a good night’s sleep. It will emit cleaner air, trapping any allergens that may be present in the room and helping to remove the cause of the sneezing or coughing.

Benefit 8: Household cleaning is made easier

Because an air purifier traps a significant amount of dust in the home; the floors, furniture and many other surfaces might stay cleaner longer. In particular, surfaces such as the tops of kitchen cupboards which people probably never think about, will be cleaner.

Benefit 9: Reduce mold

If you notice some black spots in the bathroom, they could be mold. Mold spores can travel throughout the house, carried in the air as it circulates the rooms, triggering serious symptoms in people prone to allergy and respiratory problems. An air purifier can capture some of the spores, but the source of the mold should be investigated and remedied.

What Are The Benefits of a Humidifier?

A humidifier may be of benefit to your family while sleeping. Sleep helps to bolster, rejuvenate and repair the immune system.

Benefit 1: Fewer cold and flu symptoms

In a dry air environment, you are more susceptible to colds and flu, so having a humidifier raise the humidity levels in your home allows viruses to attach to the water vapor particles and fall out of the air, rather than attaching to our bodies and infecting us.

Benefit 2: Helps loosen congestion

Dry air can cause the nasal passages to become clogged due to mucus becoming dry and thick. This can make your nose feel stuffy and give you sinus pain and a sore throat. Adding moisture to the air with a humidifier may help remove the congestion.

Benefit 3: Flu and cold recovery time will be reduced

If you or a family member catches a cold or flu, a humidifier in the bedroom may reduce recovery time. Not only will the increased humidity help to loosen congestion, but it may moisten the nasal passages, allowing for easier breathing.

Benefit 4: Helps prevent dry skin

If the air in your home is dry, it may cause dry skin, which could crack easily and be prone to wrinkling. Using lotions and creams to combat the problem may not rehydrate your skin. More moisture in the air may help, as your skin can constantly absorb it.

Benefit 5: Overall air quality improvement

A humidifier can improve the overall quality of the air in the home. Moist air is more beneficial to your health, particularly if you suffer from respiratory illnesses or allergies. Contaminants in dry air make breathing harder; if you become ill, the symptoms last longer.

Frequently Asked Questions About Humidifiers and Air Purifiers

🤔 Can I use a humidifier and air purifier in the same room?

Yes, a humidifier and an air purifier can be in use simultaneously. Each performs a different function. One adds moisture to the air, while the other cleans the air, so you get the best of both worlds. Clean, moist air in the room where they are situated.

🤔 Do humidifiers clean the air?

No. Humidifiers do not improve the air quality in the home. They neither enhance the quality of air nor remove any pollutants from the air in the home. Humidifiers only add water vapor to the air, increasing the overall humidity.

Final Thoughts 

You should now be aware of how each device will suit your needs when you are undecided about choosing a humidifier or an air purifier. As you will have gathered, both units can have a beneficial effect on your health. Many homeowners install both to achieve the level of relief and comfort they require.


Ashton, D. (2022). 53 Indoor Air Quality Statistics.
Park, K.H. (2020). Effects of Air Purifiers on Patients with Allergic Rhinitis: a Multicenter, Randomized, Double-Blind, and Placebo-Controlled Study.
Unites States Environmental Protection Agency. (2022).What is a HEPA filter? epa.govMcDonald, E et al. (2002). Effect of air filtration systems on asthma: a systematic review of randomized trials.
About the author

Danny Ashton

Danny is the founder of HouseFresh and has been writing about air purifiers and indoor air quality since 2010. He is our lead tester, conducting all the tests we use to evaluate air quality products. That is why you will always see his name attached to our reviews.