A lot of people use air purifiers at home. A good number also use humidifiers. Some people even have both.

Both an air purifier and a humidifier do great things to improve indoor air. But it can be difficult to understand which option is best for your particular needs. For example, both products are great for people with sinus and respiratory issues; however, the way they offer relief is different.

But do you know what qualities make these devices the same and what makes them different?

In this post, we’re going to explore the air purifier vs humidifier question so you get a clear understanding of how each of these powerful machines works. By the end of this guide, you’ll know once and for all, do you need an air purifier or humidifier in your home, or both.

Air Purifier vs Humidifier

The main difference between an air purifier and a humidifier is that air purifiers are designed to clear the air of allergens, dust, mold and control odors. Humidifiers control the humidity level in a room and do nothing to control air quality or the numbers of particles in the air.

Comparison Chart

This chart will give you a quick overview and comparison between air purifiers and humidifiers. If you want a more in-depth and comprehensive answer, read on.

CriteriaAir PurifierHumidifier
ApplicationUses filters to trap and remove airborne contaminantsAdds moisture to the air to soothe irritation caused by dry conditions
BenefitsBeneficial for asthmatics and allergy sufferers, and people who want clean airBeneficial for asthmatics and people with irritated respiratory tracts due to dry air
RemovesAllergens, Dust, Pet Dander, Mold Spores, Bacteria, and SmokeDry Air
N/A30% to 50%

Note: Our site includes a ton of free resources on air purifiers. If an air purifier sounds like something you want, take a look at our top air purifier reviews page.

If you suffer from asthma, you may want to check out our best air purifier for asthma and allergies guide. If a humidifier is sounds like more your speed, see our best humidifier for allergies guide.

Difference Between Air Purifier and Humidifier

Although you may assume that air purifiers and humidifiers can be used interchangeably, this simply is not the case. Read on to find out why.

Air Purifier

What does an air purifier do? An air purifier’s purpose is to remove a variety of airborne contaminants from your indoor air. It traps and removes dust particles, bacteria, allergens, mold spores, pet dander, smoke odors, and other harmful particles. When your air purifier runs, it sucks your home’s air into the machine and through a series of filters.

One of these filters is often called a HEPA filter, and it can capture tiny particles down to 0.3 microns. The True HEPA version of this filter is 99.97% effective at removing airborne contaminants that irritate allergies, asthma, and other respiratory conditions.

If you’re wondering what are HEPA filters made of, then it’s a tightly woven set of plastic and fiberglass threads that allow air to pass through while trapping particles that are larger than the openings within the material.

Keep in mind that an air purifier doesn’t add any moisture back into the air. It only functions to clean and filter out the pollution.


What does a humidifier do? A humidifier’s main function is to add moisture back into your home’s air. It does this by pumping water vapor into a room that may or may not be visible. Compare that to a humidifier vs dehumidifier where the latter removes water vapor from the air.

To keep the humidifier running, you must continue to add water to a reservoir. It converts this water into a fine mist and expels it into the surrounding air.vHumidifiers are best used in dry areas because they add moisture back into the air. Humidifiers can help relieve dry skin, throat irritation, sinus issues, nosebleeds, and breathing problems you may experience by being in an arid climate.

It’s important to know that a humidifier raises a room’s relative humidity level. If you already have high humidity levels, this can encourage mold growth. Therefore, you want your indoor humidity levels to stay between 30% and 50%.

Below 30% is considered too dry and can cause the issues we mentioned in the last paragraph. Over 50% humidity can encourage mold growth, dust mite reproduction, and mildew.

If you can’t lower the humidity levels sufficiently, then it’s best to have a good air purifier for mold spores in the home to extract the fungi from the air.

Types of Air Purifiers

Air purifiers come in various types and each unit can contain one or more of the following air cleaning functions:

HEPA Filtration

This is a highly dense filter that traps airborne contaminants. A “True HEPA Filter” is the best kind to look for on an air purifier because it’s certified to remove 99.97% of all particles as small as 0.3 microns in size. It’s good for removing pollutants like allergens, particulate matter, dust, visible smoke, and pet dander.

Carbon Filtration

This filter contains a special form of activated carbon that traps gases, odors, chemicals, and volatile organic compounds (VOCs). It helps keep a home smelling fresh and reduces toxic substances that are in the air.

Negative Ionization

This air cleaning technology emits charged ions into the air that latch onto airborne contaminants. This process weights particles down so they can be more easily captured by the internal air filters as well as causes pollutants to fall onto the floor. This process can remove ultra-fine particles down to 0.01 microns in size.

Ultraviolet (UV) Light

This is a special light that kills airborne bacteria and viruses by destroying their molecular DNA structure. As air passes through the air purifier, the UV light zaps microorganisms and pathogens so that the air flowing back into the room is sterilized and clean.

Air purifiers also come in two forms: portable and whole house air purification systems. We primarily recommend portable air purifiers because of their cheaper cost and efficiency for single rooms. But if you want an air purifier that can clean the full volume of air that flows through your furnace, check out our best whole home air purifier guide for more details.

Types of Humidifiers

Humidifiers come in three common types:

Warm Mist

These humidifiers heat up water with a gentle boiling process to produce a warm mist that you can see and feel in the air.

Cool Mist

These humidifiers contain a filter that traps sediment, minerals, and other impurities while delivering a cool invisible mist that evaporates into the air.


These humidifiers use a metal diaphragm that vibrates at an ultrasonic frequency.  This process creates water droplets that are pushed into the air with a fan to create a cool lighter mist that quickly disperses humidity into the room.

How Do Air Purifiers and Humidifiers Affect Your Health?

Air purifiers and humidifiers affect the air quality in our homes, therefore having an effect on our health. They both treat the air we breathe in but in very different ways.

So, what are the differences and which one will be most beneficial? That depends on what is causing the symptoms that need to be treated. Neither machine is a cure but still helpful.

Air purifiers pull small particles from the air and trap them in a series of filters. This helps reduce allergens in the air, including dust mites, pet dander, pollen, and mold spores. There are some purifiers on the market that can also remove Volatile Organic compounds or VOCs. These compounds are toxic and are found in many of the cleaning products we use in our homes daily.

Humidifiers do not clean the air and have no impact on the number of airborne allergens. Instead, these machines only add moisture to the air. Using a humidifier to add humidity to a room can help relieve a stuffy nose, itchy throat and eyes, dry skin and hair. If you maintain a humidity level of 40 to 60 percent, there can also be a reduction in the potency of the viruses that are in the air.

If the dry air in your bedroom is causing a snoring issue, adding a humidifier can also help stop the snoring or lesson it by adding moisture to the nasal cavities. Humidifiers can also help reduce nose bleeds caused by dry air.

Which is Better for You: An Air Purifier or Humidifier?

An air purifier might be best if:

  • You suffer from asthma, allergies, or a respiratory condition that’s irritated by polluted air.
  • You want to decrease the amount of pet dander or allergens present in your home’s air.
  • You want a good dust remover machine to reduce the amount of dust that accumulates indoors.
  • You want to get rid of household odors due to cooking, pets, smoke, or mold.
  • You want to reduce the level of toxic substances in the air you breathe.
  • You want to sleep better at night with less lung, throat, and nose irritation.
  • You want a cleaner, more sterilized home environment.

A humidifier might be best if:

See all of Amazon's Best Selling Air Purifiers

Frequently Asked Questions

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

You can use an air purifier and humidifier in the same room. You can also use them at the same time. Each device serves a different purpose. An air purifier cleans the air from pollutants while a humidifier adds moisture to the air for better comfort.

The air purifier will clean the air of pollutants while the humidifier adds moisture back into the air to make it more comfortable to live and breathe.

Do humidifiers clean the air?

A humidifier does not clean the air. However, it does serve a valuable function in the home. Instead of cleaning the air, humidifiers add moisture into the air to improve humidity levels. This can make the air more comfortable and easier to breathe compared to dry air.

Do humidifiers help with dust?

Humidifiers do not help with dust. A humidifier adds moisture into the air and has no effect on cleaning the air from dust particles. Moisturizing the air with a humidifier can create the perfect home for dust mites to live and prosper if you do not keep the humidity level between 30-50%.

Air purifier vs humidifier for baby?

You could use both. An air purifier will give your baby cleaner air in their room and help promote better health.

If the air is dry, a humidifier will add moisture back to help your baby breathe and feel more comfortable and help reduce cough and cold symptoms. Using a cool-mist humidifier may help to shrink the nasal passages allowing infants to breathe better. A warm mist humidifier can cause the opposite to happen (swelling of the nasal passages) and make breathing more difficult.

Placing an air purifier into the baby’s room will help keep the air clean and remove unwanted particles from the air. See our best air purifier for baby guide for the top product reviews. Air purifiers can reduce the number of contaminants that could cause cold and flu illnesses. They also pull particles out of the air from toxins in tobacco smoke, gasses emitted by some plastics, mold spores, pet dander, and pollen.

Air purifier or humidifier for asthma?

Both devices work well but an air purifier is the best choice.

An air purifier removes common asthma triggers from the air so you don’t inhale them. A humidifier won’t remove the triggers but can make the air more pleasant to breathe. For those with asthma, a humidifier can ease the symptoms if they are being caused by dry air. It does not affect asthma as in curing it or stopping an attack from happening.

One thing to keep in mind is that if you use a humidifier for a prolonged period of time and increase the humidity level above 60 percent, then these machines may make your asthma worse or trigger an attack. That’s because high humidity levels can increase the reproduction of harmful bacteria, dust mites, and mold. Therefore, an air purifier is best for asthmatics for long term use. When pollutants are taken out of the air, there is less chance for an attack to be triggered.

Air purifier or a humidifier for allergies?

An air purifier is the best option for allergies. Air purifiers remove dust, pollen, pet dander, mold spores, and more from the air so they don’t end up in your eyes, throat, or lungs. A humidifier doesn’t remove these items, and may actually increase them if the humidity level gets too high.

If reducing allergens is the goal behind the purchase, then an air purifier is what you’ll want. Using a high-quality True HEPA filter will help to trap allergen particles down to 0.3 microns in size.

Humidifiers, on the other hand, can make allergies worse. The added humidity can help dust mites survive and mold to grow. With a humidifier running, the air quality is the same with just more moisture added.

Bottom Line

By now, you should know which device will work better for your circumstances when you’re choosing between an air purifier vs humidifier. As you learned, both a humidifier and air purifier can be beneficial for your health and home. And in many instances, people choose to use both indoors to get the comfort and relief and they need.

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About David Morrison

David is an Air Quality & Comfort Technician. He has expert knowledge on the technology and design of air purification, air conditioning, and heating systems. His main role is to write content that helps people get the most value out of their air purifiers, air conditioners, and heating units. (See Full Bio)