A Beginner's Guide To Air Purifiers: How It Works And Our Top Picks

During my formative years, I suffered horribly from airborne and pet allergies, with side effects as little as a runny nose up to itchy and swollen eyes, hives and trouble breathing. At the time, antihistamines like Claritin were only available from a prescription, so I’d just grab a Benadryl for the days it was severe and struggled not to fall asleep in math class.

I’m definitely not alone in my childhood suffering. According to the Asthma and Allergy Foundation of America (AAFA) and data from the Centers for Disease Control and Prevention (CDC), more than 100 million people in the U.S. experience some type of allergy each year, with allergies ranking as the sixth leading cause of chronic illness in the U.S. Don't forget to check out The Weather Channel's 15-day allergy forecast, especially when you're planning to be outdoors for any length of time..

And while outdoor air quality is certainly a trigger for seasonal allergies, indoor air quality is just as important when it comes to managing your symptoms. In the following guide, we’re taking a deeper look into how indoor air pollution can affect you, and why air purifiers may be able to help those suffering from allergies. We also researched some of the best air purifiers on the market today and narrowed down our choices based on multiple criteria, including room size, price and functionality.

What Is Indoor Air Pollution?

Indoor air pollution can appear in a variety of forms, from dust and mold to pet dander and smoke. Even cleaning supplies can introduce a number of different chemical compounds into the air. Indoor air pollution can cause a number of side effects, like irritation of the eyes, nose and throat, headaches, respiratory disease and even more serious illness, according to the U.S. Environmental Protection Agency (EPA).

How Do Air Purifiers Work?

Air purifiers, also known as portable air cleaners or air sanitizers, are designed to filter the air of a single room or area to reduce (but cannot completely eliminate) indoor air pollution.

You need to look at the “clean air delivery rate” (CADR) to determine if it's large enough for the size of the room you’ll be using it in. Portable air cleaners will get a higher CADR by using a “high-efficiency particulate air” (HEPA) filter.

CADR was established by the Association of Home Appliance Manufacturers (AHAM) to determine the effectiveness of an air cleaner. The higher the CADR, the faster the unit is filtering the air.

According to the AHAM, the CADR of your air cleaner should be equal to at least two-thirds of the room’s area, so in its example, a room with a dimension of 10x12 feet has an area of 120 square feet, and should have an air cleaner with a smoke CADR of at least 80.

Different Types Of Air Purifiers

There are three main types of air purifiers: Ozone-generating air cleaners, electronic air cleaners and filtering air cleaners.

1. Ozone-generating air cleaners (Not Recommended): These devices purposefully create ozone to clean the air through chemical interactions that will change the compounds of pollutants, but can cause other harmful chemical reactions. Ozone is considered a lung irritant.
2. Electronic air cleaners (Not Recommended): These can include ionizers and UV light, and are a type of air purification system that uses electrical fields to trap airborne particles, passing contaminated air through a series of charged plates or meshes, according to one source. They are not, however, effective at removing gases and odors, and may also produce ozone and other irritants as well, according to the EPA.
3. Filtering air cleaners (Recommended): Just as the name suggests, these work by passing air through a filter where pollutants are trapped, usually through carbon filters or HEPA filters.

HEPA filters do not remove gases from the air, but are generally accepted as the best at filtering particles (like dust or pollen). The effectiveness of a HEPA filter is tied to how tightly bound the fibers are, with ratings from MERV 12 to MERV 17, with MERV 13 considered the minimum you should be looking for according to Heathline.

To filter gases, it is suggested by the EPA that you choose a portable air cleaner with an activated carbon filter or other absorbent filter designed to remove gases.

It’s also important to note that neither the EPA nor Food and Drug Administration (FDA) recommend any particular air cleaning devices or manufacturers.

Can Air Purifiers Help With Allergies?

According to many sources, yes, air purifiers can help clear the air of allergens like dust, pet dander, pollen and other pollutants. Air purifiers only catch smaller particles and are usually only designed for one room, so it’s important to take other steps to keep your environment as clean as possible. Keeping your home well ventilated, clean and your HVAC filters also regularly swapped out can go a long way towards reducing your symptoms.

Best Air Purifiers Of 2024

1. Best Overall: LEVOIT Air Purifier Core 300S-P (Wi-Fi Enabled and HEPA)

Price: $149.99 at Amazon; $149.99 at Levoit.com

Best Budget Pick: LEVOIT Air Purifier Core 300-P (Basic Purifier) - $84.93, was $99.98 at Amazon

Filter Type: HEPA & Carbon | Effective Range: 219 sq. ft. (up to 1,000 sq. ft./1 hour) | CADR: 140 CFM | App: Yes

Other features:

• 3-in-1 filtration system: Pre-filter, multi-layer filter and activated carbon filter
• Multiple filter options: Pet allergy, toxin absorber, or smoke remover filter
• Sleep mode turns off display and reduces noise level
• App and voice assistant compatible
• Company claims Energy Star Certified, FCC Certified, ETL Certified, CARB Certified

The Levoit Core 300S has over 101,000+ ratings, 4.7-stars and is the best seller on Amazon, with over 2,000 Levoit products purchased in the past month. There are a number of different packages available, starting with just the basic purifier, different filters and the Wi-Fi-enabled purifier (which is what we’ve listed).

In Auto mode, the Core 300S will sense changes in the particle pollution and adjust fan speeds, according to the company. In Sleep mode, the air purifier will also work more quietly, which is ideal for light sleepers.

There are over 79,000 5-star ratings alone on Amazon, with the reviews glowing. One reviewer said, “This unit cleans very well for its size. [It] is quiet and it sets up very easily, the Bluetooth connection and functionality are very well laid out and easy to manage.”

Another said, “This air purifier has made a significant difference in the quality of air in my apartment. No cigarette smoke, less disgusting odors from neighbors that I share walls with. I would recommend this item.” One mentioned, “[I] haven’t had indoor allergies bothering me with it running.”

For pet owners, multiple reviewers mentioned it is very handy at eliminating odors, “I never seriously considered using an air purifier before, but as a cat owner, I was curious about how it could help combat the persistent smells. I’m happy to report that this device has eliminated almost all of the odors and kept my bedroom feeling clean and fresh.”

The main complaints from users were how loud it could be, concerns about the longevity of the product, and some mentioned there was a bad smell with their products and that it didn’t clean the odors air as much as they had expected.

2. Best Air Purifier For Large Rooms: Medify MA-50 Air Purifier With True HEPA H13 Filter

Price: $242.99 at Amazon

Filter Type: HEPA & Carbon | Effective Range: 2,640 sq. ft./1 hour | CADR: 598 | App: No

Other features:

• 3-in-1 filtration system: Pre-filter, True HEPA H13 filter, and activated carbon filter
• HEPA H13 Filtration: captures finer particles than HEPA H11, and is trusted to remove particles, allergens, odors, smoke, pollen, pet dander, smog and more, according to the company page
• Touch screen with up to 12-hour timer, four fan speeds, sleep mode, filter replacement indicator and child lock
• Filter lasts 2,500 hours (approximately 3-4 months)
• Company claims Energy Star Certified, ETL Certified, CARB Certified in 2023

T​he Medify MA50-Air Purifier currently has 4.6-stars and over 21,000 ratings on Amazon for all of their air purifier options. With HEPA H13 filtration, you'll be getting some of the smallest particles trapped in this air purifier, especially when compared with other air purifiers which use lower quality filters. One of the reasons we picked the MA-50 version (rather than a smaller option like the MA-40) is that this product version came without the UV light and ionizer option, which according to some of our research may be more likely to produce ozone.

Most reviewers that use the Medify MA-50 Air Purifier in their home say they keep it at the lowest setting for the quietest results - once you start getting into the higher fan settings, you’ll notice it can get loud and vibrate a little. Using it at a higher fan setting for a shorter period of time, however, is recommended if you’re trying to reduce some odors in the room (especially after cooking, according to one reviewer).

As one reviewer puts it, “We have a bunch of Medify air purifiers - the small ones for rooms and big ones for bigger areas - and I wish I had this unit just a little earlier.” Another said, “This air purifier is the definition of ‘you get what you pay for.’ In that I mean both the unit and the replacement filters are ridiculously expensive...but they actually work! I am simply amazed by how much better I feel when I'm in the same room as this filter.”

Some complaints were that the MA-50 unit didn’t last beyond two years, and the noise level at the higher settings is disruptive. Others felt that the replacement filters were too expensive.

3. Best Air Purifier For Medium Rooms: Clorox Air Purifier

Filter Type: HEPA & Carbon | Effective Range: 225 sq. ft. (up to 1,000 sq. ft./1 hour) | CADR: ~142 CFM | App: Yes

Other features:

• 3-in-1 filtration system: Pre-filter, True HEPA filter, and activated carbon filter
• Comes with air quality sensor with real-time digital display
• 1, 4 or 8-hour timer, four fan speeds, auto and sleep mode, child lock
• Filter lasts approximately 6 months
• C​ompany claims Energy Star Certified

If you’ve decided the Levoit isn’t quite right for you, and you want to save a few bucks, take a look at the Clorox Air Purifier as a competitive alternative. This size is ideal for medium rooms and depending on the size of your ceilings it can circulate air up to 225 square feet of space five times an hour, according to the company page.

It has over 1,000 total ratings (an average of 4.6 stars), 800+ which are 5-star ratings on Amazon. Most of the reviews are also very straightforward, with many saying they are happy with the overall performance, effectiveness and price of the model.

As one stated, “I am very happy with this air purifier. The reviews were good, the cost was reasonable, and it works. I have definitely noticed a reduction in stale odor as well as dust since purchasing this. It’s also extremely quiet. It’s also small enough to tuck into an unobtrusive yet functional space. My neighbor purchased two as a result of my recommendation.”

Another said, “This purifier runs silent and is perfect for a dusty environment like a work office. Practically no set up required. Just plug it in and turn it on. [The] filter can be removed and be blown out with an air hose and be reused so that you don’t need to buy expensive replacement filters like so many other models. Recommend!”

As for complaints, it was largely around the longevity of the product, the filters not lasting as long as the company says they should, and not getting as much square footage coverage as expected. The square footage stated is based on eight-foot ceilings.

4. Best Air Purifier For Pets: Shark HP201 & HP202 Clean Sense Air Purifier MAX

Price: $248.99, was $329.99 at Amazon (HP201); $279.99 at SharkClean.com (HP202)

Filter Type: HEPA & Carbon | Effective Range: 256 sq. ft. (up to 1,000 sq. ft / 1 hour) | CADR: ~165 CFM | App: No

Other features:

• True HEPA Multi-Filter with Microban® antimicrobial coating

• Clean Sense IQ: Monitors air quality, adjusts power and reports results
• Four fan speeds, eco mode, auto and sleep mode with dimmable lights
• Filter lasts approximately 6-12 months
• Company claims UL Certified, Energy Star Certified, CARB Certified

I've tested a number of Shark products over the past few years, and have been a long-time fan of their variety of high-performing vacuums, robot vacuums and mops, grills and more. This Shark HP201 Clean Sense Air Purifier Max claims to clean up to 1,000 square foot rooms in up to one hour, and is ideal for targeting common allergens like dust, dander and smoke. This air cleaner has a proprietary filter that the company claims to exceed normal HEPA standards, and it's most ideal to use in bedrooms, living rooms, dining rooms and even basements.

The HP201 model currently has 4.6-stars and over 1,100 ratings on Amazon, while the HP202 model on SharkClean.com has 4.7-stars and 184 reviews. As one reviewer said, "My daughter has allergies and we have two cats. This cleaned up the air in a large room. [It] was so quick and easy to set up and turn on. Iti s super quiet, which I love." Another said, "We have two dogs who are over 100 pounds and have long hair. They bring in all kinds of dust, dirt and dander...we got this for the bedroom. I noticed a sudden decrease in dust in our bedroom. I also like the white noise it provides."

F​or complaints, some reviewers didn't really like the auto features, as it would kick on even when displaying good air quality, they felt the air quality sensor wasn't reliable, and the replacement filters are expensive.

5. Best Air Purifier For Small Rooms: Blueair Pure Mini Max

Price: $69.99 at Amazon, Bundle: $125.99, was $139.99 at Blueair

Filter Type: Carbon | Effective Range: 93 sq. ft. | CADR: 60 CFM | App: No

Other features:

• HEPASilent™ filtration system: Fabric pre-filter, main filter and activated carbon filter
• Three fan modes
• Washable fabric pre-filter

The Blue Pure Mini Max is our pick if you’re looking for an air purifier for a small room on a decently low budget. If you have a small bedroom or office, this could be all the air purifying power you really need.

One of my colleagues has multiple sizes of the Blueair purifiers, and said “I’ve noticed a significant change in the air quality of my home. The air is cleaner, less allergens - and even my pets are sneezing less. There are three settings, so if you like white noise you can set it louder, while I prefer it to be quiet. The light sensor that lets you know when the filter needs to be cleaned is also very handy.”

There are no air sensors, app or smart assistant options like the Levoit, but if you don’t need any of those extra features, why pay for it? The other Blueair models, like the 411 Max, also have high reviews with a few extra bells and whistles if you don’t mind paying a little more. No matter the model, though, you should plan to replace the filter every 6 months.

Many of the reviews are pleased with how quiet the Blueair products are, with one saying, “We have been users of Blue Air filters for years…We have noticed an improvement in the amount of dust and the air quality in our home.” Another one said, “It is extremely quiet and I noticed a difference in air quality in record time. I suffer [from] allergies this time of year and having this device in my office has been a game changer!”

However, other reviewers complained about a plastic smell from their air purifier and slow customer service times. Some of the Blueair products have been reported to have some ozone emissions though the company does claim its within safe limits.

M​ore Reading On Air Purifiers

I've been spending a lot of time researching various air purifiers, from performance and features, first-hand testing, positive reviews and complaints. If you didn't find exactly what you were looking for, whether it was room size, price point or safety features, be sure to check out some of our reviews and deal guides as you continue your research.

• Best Budget Air Purifiers of 2024
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M​ore Reading On Home Products

T​his season is going to be hot, humid and stormy according to the Weather.com summer forecasts. Stay cool - and dry - with some of these highly rated products. Not sure what portable air conditioner size you need for your garage, workspace or bedroom? We've got you covered. If you're suffering from terrible humidity in your basement or crawl spaces, we detail how to determine when, and what, dehumidifier might be right for you.

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How We Made Our Decision

Safety

During our research on these products, we attempted to ensure that we avoided ozone and ionizer air purifiers specifically due to the guidance from the EPA. One company on our list, Blueair, has somewhat questionable documentation out there, though has claimed the product is within acceptable standards. While we recommended the Blueair Pure Mini Max because of the general quality of the performance and reviews, if budget and room sizes aren’t an issue, we might suggest upgrading to the Levoit.

First-hand testing

One of our top picks included Blueair because of the very positive feedback and extensive use. My colleague has multiple sizes throughout the house, and highly recommended the selection. As mentioned in the review, they saw a noticeable difference in air quality after purchasing this product.

Functionality

When pulling together our best-selling list of air purifiers, we were looking at a few different performance criteria: multi-option filtration, CADR metrics and square footage, smart home or touchscreen features, and filter lifespan. We also visited AHAM Verifide and EnergyStar.gov to cross check performance claims when applicable.

Price

We love a good deal, but when it comes to your health, sometimes the age-old adage “you get what you pay for” is all too true. We wanted to keep our picks below $300 while still providing valuable performance.

Reviews

We let the reviewers speak for themselves when it comes to hands-on testing. We strive to highlight the pros and cons of each product based on user feedback and the feature list. If a product has few (or no) verified reviewers, or the complaints outweigh the purpose and price of the product, we won’t feature it in our lists.

P​rices are accurate and items in stock at publish.