How to Know if You Need an Air Purifier, a Humidifier, or a Dehumidifier


Living With Allergies

How to Know if You Need an Air Purifier, a Humidifier, or a Dehumidifier

Photo of a person in soft focus sitting at a desk in their home with a plant in the foreground.

Photo by Allie Lehman via Death to Stock

Have you tried an air purifier? What about a humidifier?

If you deal with allergies, you’ve probably been told to buy something that could help you improve the air quality in your home (and, as a result, your allergy symptoms).

But if you’ve previously rolled your eyes and avoided making this type of purchase, it’s time to reconsider. Systems like HEPA filters, air purifiers, humidifiers, and dehumidifiers can help you manage your allergies by reducing allergy triggers or even changing the composition of the air.

All of them can be effective, but in different ways. Let’s talk about what each of them does and how you can choose the best option for you.

What are the different types of air filtering devices?

Take a stroll down the right aisle of your pharmacy or home improvement store and you’ll find shelves full of devices that promise to quite literally have you breathing easier. Some of the most common? Humidifiers, dehumidifiers, air purifiers, and HEPA filters.


A humidifier’s only job is to increase the level of moisture in the air. As the U.S. National Library of Medicine explains, dry air can cause your nasal passages and airways to become inflamed, which worsens your allergy symptoms. The humidifier works against that by increasing the humidity level.

Is a humidifier good for allergies? Well, yes and no. This device won’t actually minimize or eliminate any allergy triggers in the air. However, pumping out more moisture can help relieve and improve your congestion and sore throat.

Plus, if you notice that your skin is dry, your lips are cracked, and you’re frequently experiencing shocks from static electricity, that’s a good sign that a humidifier will make your whole house a lot more comfortable beyond your allergy symptoms.


Just like the name implies, a dehumidifier does the exact opposite of a humidifier: it removes moisture from the air.

But wait...if dry air is hard on your nasal passages, why would you want to take down the moisture level in your home? Well, the Asthma and Allergy Foundation of America explains that certain allergy triggers—especially dust mites and mold—thrive in damp and moist environments.

If you know that one (or both) of those kickstarts your allergy symptoms, then the last thing you’ll want to do is increase humidity. Instead, a dehumidifier will likely be a better option.

Air purifier

While humidifiers and dehumidifiers are focused on the composition of the air, an air purifier sets its sight on the contaminants that are floating around.

Again, the answer is in the name of this one: An air purifier cleans the air in your home by passing it through a series of filters. An air purifier for your whole home will be installed in the ductwork of your existing HVAC system, while a portable air purifier is a smaller unit that will filter the air in a specific area.

Do air purifiers work for allergies? The short answer is yes. The American College of Allergy, Asthma, and Immunology says that these air cleaning systems can reduce the airborne allergens present in your home, especially pollen, mold spores, and animal dander.

HEPA filter

As you peruse different air purifiers and cleaners, you’re bound to see the term “HEPA filter” crop up. This is an acronym for “high efficiency particulate air.”

To put it simply, it’s a fancy term for a super effective type of air filter—in fact, the Environmental Protection Agency (EPA) says that it can remove at least 99.97% of dust, pollen, mold bacteria, and other airborne particles of a certain size.

Unlike the other options on this list, a HEPA filter isn’t something you’ll purchase and use on its own. Instead, it’s a specific type of filter that you can use in a variety of appliances, including air purifiers (whether they’re portable or whole-home units) and vacuum cleaners.

How can you decide which is right for you?

There’s no shortage of options available to you, and we’ll admit that choosing can feel a little overwhelming. We won’t leave you to throw a dart at a board. Here’s a handy guide you can use to figure out which route you should go:

Go with a humidifier if…

  • You live in a particularly dry or cold climate.
  • You’re experiencing symptoms of extremely dry air, such as chapped lips, bloody noses, a wheezy cough, or frequent static electricity shocks.

Go with a dehumidifier if…

  • You live in a particularly damp climate.
  • You have an area of your home that sees a lot of extreme moisture, such as a basement or a bathroom.
  • You know that dust mites or mold are allergy triggers for you, as they thrive in moist environments.

Go with an air purifier if…

  • You know that you have allergy triggers present in your home (such as dust or dander from your roommate’s cat).

If you do decide to go with an air purifier for allergies, make sure to look for one with a HEPA filter to experience the most benefit.

Still struggling to decide or wondering which is better for allergies: an air purifier, humidifier, or dehumidifier? Don’t be afraid to use a combination. While you shouldn’t use a humidifier and dehumidifier together (since they’d only work against each other), either one can be used simultaneously with an air purifier (with a HEPA filter, of course) for maximum effectiveness.

Can one of these purchases ever make allergies worse?

When your goal is to relieve your allergy symptoms, the last thing you want is to realize that the brand new purchase you just unboxed and set up is making your sniffling and sneezing worse.

Unfortunately, that can happen—but you can avoid it. To do so, make sure that you:

  • Choose the right system for you: If you’re experiencing congestion because dry air is causing inflammation of your nasal passages, setting up a dehumidifier will only kick your symptoms into high gear.
  • Commit to proper cleaning and maintenance: All of these systems are ripe for bacteria if you don’t clean them properly and regularly. Follow the instructions to clean and disinfect your equipment so that you don’t spread mold or other irritants around your home.

Doing so will help you ensure that whatever air improvement device you go with actually helps you rather than hurts you.

Take steps toward an allergen-free home

An allergen-free home can be tough to achieve, but it’s definitely easier if you have the right tools to help. Fortunately, the above products can help you minimize allergens and improve air quality.

However, they don’t have to go it alone. In fact, they work best when they’re used alongside other changes like thorough, regular cleaning and finding a medication or treatment plan that helps keep your allergy symptoms at bay and get some much-needed relief.

Article Reviewed By

Amina H. Abdeldaim, MD MPH, Picnic Medical Director

Picnic Medication

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