Graphic of air purifier vs dehumidifier

Are you wondering what makes an air purifier and dehumidifier different?

Or how about what makes them similar?

In this post, we’re going settle the air purifier vs dehumidifier debate.

While both devices are great for people who have allergies or asthma it can be hard to figure out which is the better buy for your own health.

That’s because both air purifiers and dehumidifiers work to minimize allergens that are present in a room.

When it comes to how these products accomplish this shared goal, there are differences.

An air purifier cleans the air by circulating the room’s air through a series of filters. Airborne allergens and contaminants like dust, mold spores, pollen, and smoke get caught in the filter.

A dehumidifier pulls moisture in and lowers the room’s humidity levels. In turn, microbes and mold that thrive in damp and humid environments cannot survive.

By the end of this guide, you’ll know the know for sure, do you need an air purifier or dehumidifier for your home, or both.

Air Purifier vs Dehumidifier

The main difference between an air purifier vs dehumidifier is that air purifiers circulate air through a filter while a dehumidifier sucks in moisture. Air purifiers trap harmful pollutants in the air such as bacteria, dust, pollen, dander, and mold spores. Dehumidifiers draw moisture out of the air.

Comparison Chart

The chart below gives you a quick glance at how these two products compare. For a more in-depth answer to this topic, as well as tips on how to choose the best device for your needs, read on.

CriteriaAir PurifierDehumidifier
ApplicationRemoves airborne contaminants through the use of air filtersPulls moisture from the air and lowers the room’s humidity levels
BenefitsHelps asthmatics and allergy sufferersHelps allergy sufferers and reduces damp odors
RemovesAllergens, Dust, Pet Dander, Mold Spores, Bacteria, and SmokeMold, Mildew, and Dust Mites
N/AOver 50%

Note: If an air purifier sounds like something you need, take a look at our post on the best air purifier to see what’s available. We also have a guide on the best air purifier with washable filter if you’re looking to save the most money.

Basic Functions of Each Device

Some people think that air purifiers and dehumidifiers are interchangeable, but they’re really not.

We’ll outline why this is the case below.

Air Purifier

An air purifier’s job is to remove harmful airborne contaminants that are present in your home’s air.

This includes particles such as dust, allergens, bacteria, smoke, pet dander, and mold spores.

Air purifiers remove these contaminants by circulating your home’s air through a series of internal filters.

An air purifier with a HEPA filter can trap and lock up to 99.97% of airborne contaminants down to 0.3 microns in size. And it’s the top type of filter you’ll find in the best air cleaner for allergies.

The basic science behind what are HEPA filters made of is a material with thousands of small fibers interwoven together. This design allows air to pass through but not particles.

If your air purifier has an Activated Carbon Filter, then it can remove damp and musty smells that are caused by mold and mildew.

It’s important to note that an air purifier doesn’t reduce or control your home’s humidity levels. It only recirculates the air inside a room while removing the pollutants.


A dehumidifier’s job is to reduce the excess moisture that may be present in your home’s air.

The ideal range is to be below 50%. It does this by sucking moisture out of the air and collecting in inside an internal bucket.

Dehumidifiers don’t filter or clean your home’s air like an air purifier.

They just reduce moisture levels.

Compare that to a humidifier vs dehumidifier where the former increases moisture in a room.

However, as humidity goes down, you should notice a less damp feeling indoors as well as any musty smells that come from mold and mildew.

If you have trouble with dust mites, lower humidity can also get rid of these pests too, since they need moisture to grow and thrive.

Additionally, homes with less humidity feel cooler. The more moisture present in the air, the hotter it feels.

Types of Air Purifiers

Air purifiers come in a variety of 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 type because it removes 99.97% of particles as small as 0.3 microns in size, including dust, allergens, particulate matter, smoke, mold spores, and pet dander.
  • Carbon Filtration: This filter is made up of highly adsorbent activated carbon material that traps gases, odors, chemicals, and volatile organic compounds (VOCs). It’s especially useful for making a room smell fresh and to remove toxic substances from the air.
  • Negative Ionization: This air cleaning technology emits charged ions into the air that latch onto airborne pollutants. This process weights particles down so they can be more easily captured by the internal air filters. It also causes contaminants to stick to surrounding surfaces and fall onto the floor. This air cleaning process can remove ultra-fine particles down to 0.01 microns in size.
  • Ultraviolet (UV) Light: This light kills airborne mold, bacteria, and viruses by destroying their molecular DNA structure. As air passes through the air purifier, the UV light breaks apart fungi, microorganisms, and pathogens so that the air is sterilized and clean. A good air purifier for mold and mildew will always have this feature.

Additionally, air purifiers can be portable or whole home air purification systems. The portable units are the most popular type because they’re inexpensive and can be used anywhere inside the house without being fixed in a permanent location.

However, if you want the entire air inside your house purified without any limitations, then check out our best whole home air purifier guide to see what’s available. These units attached to the central heating and air conditioning system to filter all of the air that travels through the system.

Types of Dehumidifiers

Dehumidifiers come in three common types:

  • Refrigerant: This type of dehumidifier uses a refrigeration process to cool a metal plate where moisture from the air condenses. A fan draws air through the dehumidifier and the moisture drips into a water collection tank.
  • Desiccant: This type of dehumidifier uses a special material that absorbs water. It’s kind of like silica gel that you find packaged with electronic products. Inside the dehumidifier, a wheel consisting of desiccant turns slowly through the incoming air stream and absorbs moisture.
  • Electronic: This type of dehumidifier uses a Peltier heat pump to generate a cool surface for condensing the water vapor from the air. The condensed water is drained outside.

Which is Best for You: An Air Purifier or Dehumidifier?

An air purifier may be best for you if:

  • You have a health condition like allergies, asthma, or other respiratory issues and you need the cleanest air possible to breathe.
  • You want to reduce the number of allergens and/or pet dander in your home.
  • You want a good dust remover machine to reduce dust and have an overall healthier living environment.
  • You want to get rid of odors caused by mold, pets, smoke, etc.

A dehumidifier may be best for you if:

  • You want to get rid of a musty smell in a certain room.
  • You want to kill off or prevent the spread of dust mites.
  • You have a respiratory condition that’s aggravated by excess humidity.
  • You live in a humid area and want to lower your home’s temperature without running the air conditioner.
  • You want to reduce mold growth in a basement.

See all of Amazon's Best Selling Air Purifiers

Common Questions About Air Purifiers and Dehumidifiers

Do dehumidifiers improve air quality?

Yes, dehumidifiers can improve indoor air quality. By reducing the humidity level (i.e. moisture), you can stop mold growth, inhibit dust mite reproduction, and slow down the spread of bacteria and viruses.

For the best results, maintain an indoor humidity level of 35% to 50%.

Should you use an air purifier or a dehumidifier in your basement?

You should use both an air purifier and dehumidifier in your basement.

If you want to get rid of dampness and a musty odor, then it’s best to use a dehumidifier.

If you want to have clean, fresh air to breathe, then use an air purifier. This unit can remove dust, allergens, mold spores, bacteria, and other contaminants that are commonly found in basement areas.

Will a dehumidifier cool down a room?

Yes, dehumidifiers can cool a room because they reduce the relative humidity. High levels of humidity can make a room feel hotter because of the excess moisture in the air. Dehumidifiers can dry out the air by removing water vapor and make it feel cooler.

Do dehumidifiers clean the air?

Dehumidifiers do not clean the air. These appliances help maintain the humidity levels within your space by removing excess moisture. However, a dehumidifier can indirectly clean the air by preventing mold, bacteria and other particulates from growing, all of which could lead to a variety of health issues.

Air purifier or dehumidifier for asthma?

An air purifier is better for asthmatics because it removes the airborne contaminants that cause asthma attacks and difficulty breathing.

With an air purifier, you’ll cut down on the indoor triggers that irritate your respiratory system.

Air purifier or a dehumidifier for allergies?

While both devices can help allergy sufferers, an air purifier is the best choice. Air purifiers clean the air of allergens, mold spores, dust, bacteria, and pet dander.

A dehumidifier can only reduce the spread of dust mites and mold growth.

Air purifier or dehumidifier for mold?

While both devices can help with mold, a dehumidifier is the best choice.

Dehumidifiers remove excess moisture from the air that enables mold to reproduce and grow.

An air purifier can only remove the mold spores in the air and not fix the root cause of the problem.

Air purifier or dehumidifier for dust mites?

Both devices can help with dust mites.

An air purifier will trap and remove dust from a room, which eliminates the food source that dust mites need.

A dehumidifier will lower the humidity levels so dust mites have trouble thriving in the first place.

If you have humidity issues indoors, it’s best to use both an air purifier and dehumidifier for maximum protection against dust mites.

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

Yes, you can use both devices in the same room.

The air purifier will clean your room’s air of contaminants like dust, allergens, mold spores, bacteria, and more.

The dehumidifier will pull excess moisture out of the air which makes it harder for these contaminants to survive or come back.

Where should you place a dehumidifier?

The best place for a dehumidifier is in the room that has moisture problems. As for the specific placement of the unit, it’s best to put a dehumidifier as close to the center of the room as possible. That way it can draw extract the water vapor from all areas of the room.

Does an air purifier dry out the air?

No, an air purifier does not dry out the air. An air purifier does not remove moisture from the air. It only traps pollutant particles inside a set of filters. The relative humidity of the air does not go up or down with an air purifier running.

To learn more, check out our page on do air purifiers dry out the air.


By now, you should have a good idea on which side you’re on with the air purifier vs dehumidifier debate.

We hope you find the right product for your specific needs after reading this guide.

As you discovered, both a dehumidifier and air purifier can be beneficial in your home. And some people choose to have both for added comfort and relief.

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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)