01/06/2021 09:01

Both Air Purifiers and Humidifiers improve indoor air quality in their own way. One filters the airborne pollutants, while the other adds moisture into the air. Many have questions about how they work, whether they can be used together, and so on. In this post, we discuss air purifiers and humidifiers, their types, which one you need, and can they be used in the same room?

Only Evaporative Humidifiers can be used with all types of air purifiers in the same room. You shouldn’t use visible mist (e.g., ultrasonic) humidifiers with any air purifiers. These humidifiers comparatively produce dense mist, which can dampen the fibrous filters of the air purifier.

Let’s see  how air purifiers and humidifiers work:

Air Purifier

The main purpose of an air purifier, as the name suggests, is to improve the indoor air quality by trapping and eliminating a range of airborne contaminants. It serves to remove particulates and/or odorous pollutants from the air.

When in operation, the air purifier sucks air from indoor environments into the machine through an array of filters before releasing the clean and fresh air. HEPA filter air purifiers are the most popular ones as they are capable of trapping particles as small as 0.3 microns with 99.97% efficiency.

Besides fibrous media filters, there are other air filtration techniques used in residential air purifiers like adsorption (activated carbon), ionization, electrostatic precipitation (ESP), Photocatalytic oxidation (PCO), ozone generation, and others.

HEPA-based air purifiers are entirely safe to use at home as they don’t release any ozone or other chemical byproducts into the air, unlike electronic air purifiers.

Air Purifiers:

  • Mechanical
    • Fibrous: High-Efficiency (HEPA) or low-dense filter, only trap particles.
    • Adsorption: Activated carbon media, remove odors.
  • Electronic
    • Ionizer: Release charged ions to bring down particles.
    • ESP: Attract particles, release byproducts.
    • PCO: Chemically breaks gases and VOCs, often release ozone.
    • UV-C: Kills microorganisms, don’t remove them from the air.

Please read our article on different air cleaning technologies.


As you can roughly tell by the name, a humidifier adds moisture into the air by pumping a regulated amount of water vapor into your room. It converts water into a cool or warm mist before expelling it into the air. According to EPA – “Humidifiers are commonly used in homes to relieve the physical discomforts of dry nose, throat, lips, and skin.”

Consumer humidifiers are mainly 3 types: evaporative, ultrasonic, and steam-based. Evaporative humidifier uses a wicking filter and a blowing fan to create invisible cool moisture.

An ultrasonic humidifier produces mist from water by applying ultrasonic waves by a transducer. The oscillating ultrasonic soundwave breaks the water molecules and produces dense cool mist.

Steam-based humidifiers produce warm visible mist by boiling the water using a heating element.

Humidity in the house should usually be between 30- 60 percent. A humidity level below 30% is unhealthy for humans and pets. Also, excessive moisture in the air can encourage the growth of mold, mildew, and the reproduction of dust mites.

Most of the humidifiers in the market have a humidistat to control the desired relative humidity.


  • Cool Mist
    • Evaporative: Invisible cool mist, less condensed, louder.
    • Ultrasonic: Visible cool mist, economical, release white dust.
  • Warm Mist
    • Steam: Warm visible mist, good for winter, high energy cost.

Air Purifiers vs. Humidifiers – Which is Useful to Whom?

Asthmatic Individuals

Both devices are great for a person with asthma, but air purifiers are a better option because they remove airborne contaminatts. Humidifiers make the indoor atmosphere pleasant to breathe.


Both devices are helpful for babies. An air purifier provides contaminant-free air while the humidifier moisturizes the dry air and make it physically comfortable for babies.

Allergic People

Air purifiers trap airborne allergens into their filters, which would be beneficial for allergy sufferers. Humidifiers cannot filter the air, and excessive moisture also can make the air worse.

Air Purifier versus Humidifier – Comparison

Parameter Air Purifier Humidifier
What does it do Removes a wide range of airborne pollutants Increases relative humidity by adding moisture to the air
How it Works Air purifiers have single or multiple filters to remove airborne pollutants. HEPA filter, activated carbon, ionizers, UV-C are the most common Humidifiers produce moisture in multiple ways: Evaporation, Ultrasonic, and Hot Steam are the most common
Who needs it? Allergy and asthma sufferer, when needs to remove allergens and asthma triggers from the air Those who have dry skin issues, for making the air comfortable, improve sleep with aromatherapy
When to use All year round, more beneficial in allergic seasons Only during dry air season
Cons Electronic air filters often release chemical byproducts Condense-mist humidifiers often dampen the floors
Price Comparatively expensive Inexpensive but operational costs are much higher for some types such as warm steam humidifier

Air Purifier vs. Humidifier – FAQs

Q. What are the factors I should consider when selecting an Air Purifier?
A. You should check the filtration efficiency, CADR for room coverage, noise level, built-in air quality sensor, and others. If the air purifier has any electronic filtration, check out the CARB approvals for ozone emission.

Q. What are the factors I should consider when selecting a Humidifier?
A. You should check the mist types, water tank sizes, built-in humidistat, auto mode, and others. Evaporative humidifiers are most effective in adding moisture to the air. The ultrasonic ones are economical, but they often depress minerals into the air. Hot steam humidifiers might not be safe for kids.


Air purifiers can be used throughout the year to remove household airborne pollutants, while humidifiers can only be used during the dry season. Both help increase the indoor air quality, and you can own both to use them when needed.