Best Air Purifiers (2026): Coway, AirDoctor, IQAir, and More

Best Air Purifier for Mold

Courtesy of Air Doctor

AirDoctor

Smart 5500i

The AirDoctor 5500i is the second tower model I’ve used. (I’ve used IQAir’s standard GC MultiGas model for years.) Because of their power, tower models tend to be loud at their highest settings, so I was pleasantly surprised by the 5500i’s quiet hum. It captures both fine particulates—like mold spores—with its HEPA filters, and gases with its dual-action/carbon volatile organic compound (VOC) trap filters. The 5500i can exchange the air four times an hour in a 1,000-square-foot space, around the size of my New York apartment. And the purifier has an alert to let me know when it is time to change the filter.

It's the quietest and largest AirDoctor air purifier yet. It has a built-in sensor that has kept up with my cooking, turning its air quality indicator light red and automatically adjusting the fan speed to the highest setting. This also happens when construction in my building goes into overdrive. Yet it is quieter than the smaller AirDoctor 2000, the same model that once woke me up in the middle of the night. The 5500i caps at 50 decibels, quieter than a household refrigerator. It weighs 33 pounds, and I needed help getting the shipping box up the three flights of stairs to my apartment. Moving it around my apartment only took a slight nudge of the hand, as it has hidden casters that let it glide easily on my hardwood floor. It connects to the AirDoctor app, which allows for controlling remotely. And with AirDoctor’s hefty price tag, the disappointing one-year warranty seems short for the investment. While IQAir’s GC Multigas costs more than the 5500i, it offers a 10-year warranty option. As much as I liked AirDoctor’s performance, I might buy the more expensive and comparable IQAir model for the warranty alone. —Lisa Wood Shapiro

Smart appYesRemoteNoIdeal room sizeUp to 4,172 square feetWeightUnspecifiedNoise on highUnspecifiedFilter3-stage, dual-sided filtration uses UltraHEPA filters and dual-action carbon VOC filtersWarranty1-year limited

WIRED/TIRED

WIRED

Quiet for a tower model

Casters make it easy to move around

Connects to the AirDoctor app

TIRED

One-year warranty is scant for the price

Shipping box is unwieldy

Best Air Purifier for Wildfire Smoke

Courtesy of Rabbit Air

Rabbit Air

BioGS 2.0

The Rabbit Air is a sleek, disappears-in-a-room air purifier that punches above its weight thanks to its low price and five-year warranty. It has both a HEPA filter to trap common allergens like dust and pollen, plus that dangerous invisible PM 2.5, which can occur in wildfire smoke. It's also got an activated charcoal carbon filter to capture VOCs and odors and a negative ion generator that basically gives air molecules a static charge, making them easier to capture.

The BioGS 2.0 is able to clean 550 square feet at two air exchanges per hour and 275 square feet at four air exchanges per hour. I could clean my entire 1,000-square-foot apartment with two Rabbit Air BioGS 2.0s, and as the air purifiers are under $400 each, they're some of the more affordable options on the market. The Rabbit's built-in sensors adjust fan speeds, and the unit’s control panel illuminates in low-light settings. It also has a remote. I was disappointed that the BioGS 2.0 isn’t compatible with the Rabbit Air app, nor can it work with Amazon’s Alexa or Google Assistant like other Rabbit Air models. Still, because of its cost, quiet operation, ability, and style, this is one of my favorite air purifiers. —Lisa Wood Shapiro

Smart appNoRemoteYesIdeal room size550 square feetWeight16.8 lbsNoise on high25 dBFilterBioGS HEPA and charcoal-based activated carbon filtersWarranty5 years

WIRED/TIRED

WIRED

Sleek looks

Five-year warranty

Has a remote

Charcoal filter removes odors and VOCs

TIRED

Doesn't work with the Rabbit Air app

Doesn't work with smart-home platforms

Compare Our Picks

WIREDTIREDSmart AppRemoteIdeal Room SizeWeightNoise on highFilterWarrantyIQAir Atem X10-year warranty; quiet; has app controlNo carbon filter to remove gasesYesYes1,650 square feet7.3 poundsNot specifiedHyperHEPA filter10 yearsCoway Airmega 450Quiet; has a control-panel lock; wheels and handle make it easy to move aroundNo app control or remote; air quality indicator lights are confusing; warranty is short for the priceNoNo300–400 square feet at lower setting for recommended 5 air exchanges per hour, or can exchange air in a 821 square-foot room every 15 minutes at the highest setting24.9 pounds57.7 decibelsThree-in-one filter with vacuumable prefilter, True Green HEPA, and activated carbonOne year for air purifier; three years for motor and electrical partsCoway Airmega Mighty2No Wi-Fi needed; purifies an impressive 1,800 square feet in one hour; compact design; filter set lasts up to 12 monthsNo connected app or remote; awkward to maneuver with no wheels; color-coded lights could be confusing; limited settingsNoNo1,800 square feet15.2 pounds70 decibelsWashable prefilter, Max2 filter of activated carbon, and HEPAOne year for air purifier; three years for motor and electrical partsLevoit Vital 200S-P Air PurifierPet mode designed to capture pet hair and dander; connected app grants ability to control from anywhere; connects to Amazon Alexa or Google Assistant; affordableHEPA-grade filter only in sleep mode; color-coding system is different than standard US AQI; slightly larger than models with similar powerYesNo1,862 square feet13.2 pounds75 decibelsThree-stage filtration: washable prefilter, an activated carbon filter, and a HEPA-grade filterTwo years limitedBrondell O2+ Horizon 5-Stage Air Purifier with HEPASlim, understated design; high-quality filters; great valueNo internal air sensor; no app; no auto mode; loud at the highest settingNoNo112 square feet11 pounds80 decibelsPrefilter, HEPA, carbon filter, cold catalystTwo yearsIQAir HealthPro Plus XE Air PurifierWheels and top handle for easier moving; connected app; quiet at highest testingMassive and heavy; high price pointYesNo1,125 square feet35 pounds65 dBPre-filter, HyperHEPA filter, activated carbon filter10 years (with registration, one without)Dyson HushJet Purifier CompactElectrostatic filter for extended filter life up to five years; has a connected app; auto settingLoud at highest setting; not CARB -certified; not HEPAYesNo200 square feet or less to achieve the recommended 5 air exchanges per hour7 pounds80 dB (on my consumer decibel meter)Electrostatic filter and activated charcoalTwo yearsIQAir Atem EarthHas a handle for easier moving; environmentally friendly; indicator light rings on the control panel that shows both indoor and outdoor airIndicator lights are hard to see on the flat-top surface; loud; steep priceYesNo225 square feet to achieve the recommended five air exchanges per hour.17 pounds80 dB (on my consumer decibel meter)HyperHEPA and activated charcoal10 years, 25 years replacement and repairability guaranteeAirDoctor Smart 5500iQuiet for a tower model; casters make it easy to move around; connects to the AirDoctor appOne-year warranty is scant for the price; shipping box is unwieldyYesNoUp to 4,172 square feetUnspecifiedUnspecifiedThree-stage, dual-sided filtration uses UltraHEPA filters and dual-action carbon VOC filtersOne year limitedRabbit Air BioGS 2.0Sleek design; five-year warranty; has a remote; charcoal filter removes odors and VOCsDoesn't work with the Rabbit Air app; doesn't work with smart-home platformNoYes550 square feet16.8 pounds25 decibelsBioGS HEPA and charcoal-based activated carbon filtersFive years

Others Tested

Shark BreatheClear Max for $360: This is Shark’s newest air purifier that launched in April (we've previously tested the Shark NeverChange Air Purifier and Shark NeverChange Air Purifier Max). With Shark’s BreatheClear technology, intelligent purification automatically adjusts fan speed in response to the air around it and scans the air 3,600 times per hour. The filter lasts up to a whopping six years, and it can clean up to 1,650 square feet in an hour. This model has an updated LCD screen that has tons of information about the air around you, including metrics with graphics about air insights; historical graphs on air quality, temperature, and humidity; and pollutant information, including measurements for PM 2.5 and 10, and VOCs. To be honest, though, this air purifier slightly annoyed me: The bottom never seemed to screw in right and often fell out, and the fan auto-detected seemingly any and every potential pollutant on auto mode—something as innocuous as my cat walking by would launch it into its highest level, at about 75 decibels until it got back to a safe air level. When I conducted a test with smoke pellets in a sealed tent, the purifier didn’t auto-adjust to the pollutants, I had to manually enter and hit the button to engage. Then the air quality was at zero percent on the screen for 15 minutes, the smoke didn’t visually clear, and it seemed as if it wasn’t actually purifying. When I went to check on what was happening, I accidentally restarted the purifier and it took almost five hours for the monitor to read that it was at a healthy level again.

IQAir GC MultiGas XE for $1,600: This Swiss-made air purifier is a heavy tower model (55 pounds), but it has wheels for easier rolling, and at its highest setting, it can clean 275 cubic feet per minute (CFM). I appreciate that the air sensor’s indicator light is in accordance with US AQI colors. And the built-in sensor and IQAir app make the CG XE easy to use—in fact, the app provides one of the most intuitive user experiences of all I’ve tested. The CG XE can also capture toxic gases and vapors, and on auto mode, the fan speeds auto-adjust. It can clean the air of a large space with multiple air exchanges in an hour. I’ve been using the CG XE in the main room of an A-frame cabin with double-height ceilings (around 3,000 cubic feet) for the past two months, and it has kept my indoor air quality healthy. But with great power comes great noise. At its highest setting, the CG XE runs at a loud 68 decibels—that's just 2 decibels shy of the sound of a consumer vacuum cleaner, though it’s quiet at its lower settings. At $1,600, this workhorse isn’t cheap, but it’s an investment that’s built to last. —Lisa Wood Shapiro

Airthings Renew for $240: I wasn’t expecting to like the unassuming minimalist Renew from Airthings as much as I did. Its gray box design is so understated, quiet, and powerful that it was easy to plug it in and forget about it. The Renew is also the first purifier I’ve tested that gives the user multiple placement options: It can stand up with the air output facing up and sideways, and the entire box can lie on the floor. The Airthings app not only shows data graph-style, but it also functions as a remote that can adjust the purifier settings, including setting the panel lock, which is handy for cat owners. The control panel and the indicator light are barely there, and it’s not easy to see the tiny light letting me know my indoor air quality. At first, I thought the main drawback was size. The Renew is made for a bedroom, home office, or nursery. If you place it in a larger room, it’s going to have to run at its highest setting. The main drawback that I noticed after several months of use was the exterior prefilter. It did its job capturing pollutants, but I wasn't able to clean it, even with my vacuum. —Lisa Wood Shapiro

Coway Airmega ProX for $900: The Coway Airmega ProX is a monolith any high-ceilinged home needs. Specifically, if you’re living in an A-frame, double-height ceiling loft, or any home with a ceiling higher than 8 feet, the Coway Aimega ProX is for you. It gives off the vibe of a TARS robot from Interstellar crossed with a giant stereo speaker. It has a nice blend-into-the-room-mocha beige aesthetic and can clean the air four times per hour in a 1,000-square-foot space when running at its highest setting. And even at its highest and therefore loudest setting, it hovers around 50 decibels, slightly louder than the sound of falling rain, making it one of the quieter large tower air purifiers I’ve tested. It also has a control panel lock that is a plus for parents and cat owners alike. However, even though the 50-pound ProX has hidden handles and built-in lockable wheels, it really is just too heavy for the home consumer. —Lisa Wood Shapiro

Coway Airmega 400S for $650: Coway has yet to make a bad air purifier, and the Airmega 400S is another banger from the air purifier innovators. The 400S checks all the boxes when it comes to features. It has a reliable auto mode that adjusts the fan speed according to the air quality using its built-in air quality sensor. It also has a timer to schedule one, four, or eight hours of running time. And while it has a serviceable app, its built-in air sensor and auto-adjust fan keep me from having to micromanage settings. The question is, can this air purifier do the job without me pushing buttons or checking the indoor air quality, and do it quietly? With the Airmega 400S, the answer is yes. I just wish its 15 x 23 x 15-inch dimensions didn't make it so hard to place in a room. —Lisa Wood Shapiro

Air Doctor AD4000 Air Purifier for $429: Air Doctor makes sturdy and reliable purifiers, but as I went to pair the AD4000, I realized it had no Wi-Fi button on the control panel. At 15 pounds and nearly $800, the AD4000 should be Wi-Fi compatible, especially since it has an internal air quality sensor. Users should have the option to view indoor air quality on the Air Doctor app dashboard. And while the AD4000 is made for larger spaces, if one wanted to achieve the four air exchanges per hour that the AD4000 supposedly can do, then it would have its fan at the highest setting. My consumer sound level meter registered 100 decibels at full blast. It sounded to me like a hair dryer on a low setting. For context, the CDC’s recommendation for noise levels for workers is that they are not exposed to 100 decibels for more than 15 minutes. It’s for that reason that all air purifiers need to be in a space where they can run the fan at the lowest (or reasonably quiet) setting. The AD4000 would do well in a 200- to 300-square-foot room, where it could run on a lower setting. Also, be careful when unboxing: When I was setting up the AD4000, the sticker with instructions to take the filters out of their plastic bags pulled off the control panel when I went to remove it. —Lisa Wood Shapiro

Airdog X5 for $649: The Airdog X5 is the first washable-filter air purifier I’ve tested. And while it doesn’t use a HEPA, it is California Air Resources Board–certified. CARB lists it as electronic filtration instead of a HEPA filter; that would be listed as mechanical. As I’ve written before, if an air purifier isn’t CARB-certified, it's likely not worth buying. I tested the Airdog in a large room, and it even came with a limited-edition pet plate. That is exactly what it sounds like—a plate that fits over the Airdog meant for a cat to perch on. Neither of my cats took to it. The Airdog has a responsive built-in sensor that was in sync with my other air quality monitors. And its electronic air filters, by way of their patented TPA technology, charge particles and then capture them. The best way I can describe it is to imagine that the PM 2.5 are mosquitoes and the Airdog is like an old-time mosquito zapper. It works a little like that, and if the filter gets dirty enough, it will make zap sounds. —Lisa Wood Shapiro

Mila Air 3 Critter Cuddler for $399: Mila makes a line of filters designed specifically for pregnant people, allergy sufferers, pet owners, etc. With its built-in sensor and easy-to-use app dashboard, along with its wooden-legged modern box design, Mila is easy to love. The more I cover air purifiers, the more go big to go quiet comes to mind. Smaller models tend to run loud on their highest settings. The Mila was not as quiet as I hoped. At full blast, the Mila hit 70 decibels on my consumer decibel reader. At a CADR rating of 447 m3/hr, the Mila would do nicely in the average American 200-square-foot bedroom. You could run the Mila at its highest setting for CDC’s recommended five air exchanges an hour in a 400-square-foot room, but doing so is quite noisy. I ran the Mila in my sons’ 200-square-foot bedroom, and its auto setting adjusted correctly to the room’s air quality. And while Mila gets its outdoor AQI from PurpleAir, it couldn’t seem to find my PurpleAir outdoor monitor. —Lisa Wood Shapiro

Windmill Air Purifier for $299: I like the Scandinavian look of this bamboo purifier, and it’s more furniture-esque than other models. Still, with the blue model, the nicks in the veneer show up as white. It’s possible the bamboo finish might wear better. I really like this brand and reviewed its desk fan and air conditioner, the latter of which pairs with the Windmill Air app, and I'm equally happy using the app with its air purifier. The Windmill has an internal sensor and indicator light: green for good, yellow for moderate, pink for bad, and red for unhealthy. And while the “boost” setting is the loudest, it is still relatively quiet at its lower setting. I prefer to run it on the auto-adjusting eco mode. —Lisa Wood Shapiro

Coway Airmega 50 for $80: A mini version of the brand's Airmega 100, the Airmega 50 (see the full review) has many of the features of Coway’s larger and more expensive models and is notably affordable. The Airmega 50 was surprisingly effective for an air purifier the size of a roll of paper towels. The built-in sensor triggers both auto mode and the air quality indicator light, which gives the user instant information with nightlight vibes. One issue I have with all Coway air purifiers is the fact the custom color air quality indicator lights are different from the US AQI's six color-coded categories. Instead of green signaling good air, Coway’s green means air quality is moderate. See how it’s confusing? Blue, which is not on the US AQI color scale, means good.

Puroair 240 HEPA Air Purifier for $160: At less than 9 inches tall, the Puroair 240 is tiny. And like so many of the smaller tabletop models, it’s also loud. It might be effective in a small space, say a room about 100 to 150 square feet. It's also CARB-certified. I found its filter size too small to effectively clean an average-sized room. And while I still review smaller air purifiers, there are larger and quieter models on the market for relatively the same cost that have greater air exchanges in a larger-sized room. The Puroair’s indicator light is adjusted by the 240’s internal sensor and is green for acceptable, yellow for moderate, and red for poor air quality. At times, I found the thin sliver of the indicator’s light difficult to see. The 240 has auto or manual mode, a timer, child lock, and filter replacement light. It also has a three-stage filter, including the tightly woven HEPA 14, activated carbon, and prefilter. Lastly, the 240’s black plastic attracted a noticeable amount of fingerprints. —Lisa Wood Shapiro

Dyson Purifier Cool Gen 1 for $470: This is one of four Dyson purifiers I've tested over the years, and I continue to have a love/hate relationship with them. I admire the design and built-in air quality sensor, but there always seems to be something I don’t like with each model. Sometimes I’m not able to get a replacement remote, as Dyson moves on to new models at breakneck speed, and I’ve never really used the magnetic spot atop the filter to rest the remote. This time I was surprised that the Cool Gen1 wasn’t compatible with the Dyson app. I had to use the remote to adjust the fan speed. On the plus side, I do like the way the fan works, but this isn’t an oscillating fan in the traditional sense. Instead, the Cool Gen 1 TP10 has air blowing out of the sides of the long upright oval, and it shifts direction, aiming the cool air back and forth in a room. —Lisa Wood Shapiro

Coway Airmega 250 for $380: The Airmega 250 has a decently large footprint, but it’s rated to clean a 930-square-foot room twice an hour. That’s why I put it smack-dab in the middle of the first floor of my home to clean the air in my kitchen and living room. Every time I cook, the smart air purifier mode automatically detects unhealthy particles in the air and ratchets up the fan’s power. It also recently did this when I had someone patch some drywall in my mudroom. (This mode works with the help of a PM10 and PM2.5 particle sensor.) The fan at its highest setting isn’t that loud—I measured it at 60 decibels standing right in front of it. There’s a sleep mode if you want it silent. You get the usual controls, like timer functionality and replacement indicators for the filter. Speaking of, the Airmega 250 uses a true HEPA filter that needs to be replaced once every six to 12 months. This, combined with the washable prefilter that you should be keeping clean every two weeks and the activated carbon filter, allows the air purifier to remove 99.999 percent of ultrafine particles down to 0.01 microns, or so Coway says. It’s super easy to remove these filters to clean and swap them out. The whole system is roughly 21 pounds, so you can move it around fairly easily. Coway offers a three-year warranty. The Coway Airmega 250S is the same model but with Wi-Fi functionality, so you can control it via an app and see more details. The last thing I need is another app, but maybe you don’t mind. —Julian Chokkattu

Oransi AirMend True Carbon for $350: While other AirMend models are made for HEPA filters, the True Carbon doesn’t have a HEPA. Instead, it has a 3-pound activated carbon filter. There's a remote but no internal sensor, so raising the fan speed is a manual operation. It took a few tries using the remote, as there is a small lag time as the fan adjusts to different speeds. I appreciated the magnetic remote holder on the top of the purifier. It’s quiet on most settings and has an easy-to-miss minimalist design, blending into most spaces. The True Carbon is for those who need serious odor removal. I placed the True Carbon next to my two cats’ heavily used litter box, and within half hour the purifier eliminated the smell. I knew it was working when my son couldn’t detect an odor. I could see the True Carbon being an essential appliance for smoker households, kitchens that retain smells, or cat owners. It’s surprisingly effective, but this is for VOCs and odors. The True Carbon is HEPA-less—it cannot capture fine particulates from the air. What you gain with a supersized activated carbon filter, you lose in standard air purifying ability such as removing PM2.5. That might be fine for your needs. Oransi also makes a wall mount and handy travel bag sold separately. —Lisa Wood Shapiro

PurOxygen P500i for $170: This machine cleans the air of a smaller-than-average-sized room, and its easy-to-read display, app compatibility, side handles, and unique all-in-one filter make it easy to like. I usually stay away from small-room air purifiers due to their loud noise and less-than-ideal air-cleaning power. And while at its highest setting, the P500i reaches up to 50 decibels, it operates quietly at lower speeds and can effectively clean the air in a home office or a room smaller than 200 square feet. The PurOxygen uses a combined filter that has a prefilter that can be un-Velcroed and hand-washed, an activated carbon, a HEPA 13, and a cold catalyst filter. A cold catalyst, also known as low-temperature catalyst filtration, can cause a chemical reaction that can break down gases, like VOCs, and convert them to less harmful substances. And while the P5001 is CARB-certified as a mechanical air purifier, the Environmental Protection Agency (EPA) does not recommend catalysts due to their limited effectiveness. —Lisa Wood Shapiro

Not Recommended

Dreame Air Pursue PM20 for $600: This purifier promised to redefine air quality management, “with innovative human tracking capabilities and precision detection systems, delivering personalized air purification that adapts to every need.” The Pursue reminded me of the Dyson Purifier Big+Quiet Formaldehyde BP04 in shape, but the Pursue is designed to follow human movement, directing clean air in the user's direction. The Pursue that I tested worked well at first, but stopped pursuing early on. While this could have been user error, no amount of clicking the remote put it back into Pursue mode. —Lisa Wood Shapiro

Ikea Starkvind for $200: Ikea’s Starkvind hit the American market in 2021. It's stylish and relatively inexpensive and has the option to add on a carbon filter for gases such as benzene. It can be purchased either on its own or built into a wooden side table, but it’s worth noting that the Starkind took me an hour to assemble. While it is CARB-certified, meaning it passed the rigorous standards of the California Air Resources Board, it does not have a HEPA filter. Thinking I had an early version made for media, I went to my local Ikea. I bought a Förnuftig, and its manual listed the filter as HEPA. It’s not. I reached out to the company; at the time of publication, Ikea said it was still routing the question to the appropriate team. The question remains: If you’re buying an air purifier, why not buy a HEPA? —Lisa Wood Shapiro

Morento Air Purifier for $87: This CARB-certified model caught my attention last year for its value. With a CADR of 200 cubic feet per minute, the Morento is not only more powerful than most others at its price point, but it's got all the features of higher-end models, including a PM 2.5 sensor and ring-light indicator, plus smart capability through the Havaworks app. During the testing period, however, the fan never increased speed to compensate for higher PM 2.5 levels, even when I burned incense in the room to raise the level into the 500s. This persisted despite the machine being set to auto mode both in the app and on the machine itself, plus my cleaning the sensor and resetting the unit by unplugging it. Regardless, even if this feature had been working properly, the Morento gives a strangely wide margin for acceptable PM 2.5 levels—the ring light indicator continued to glow green (“good”) up to 75 PM 2.5, which is 15 times more than the World Health Organization (WHO)–recommended level of 5 micrograms per cubic meter. —Kat Merck

FAQs

How to Shop for an Air Purifier

How does a busy shopper find the right size purifier for a room they want to clean? The CDC recommends that one should aim for five air exchanges per hour, in a metric known as the ACH. When looking at an air purifier, look at the cubic feet per minute in airflow at the lowest setting. When measuring the cubic footage of your room, you need the area of the room times the height. Imagine a one-foot cube of styrofoam: How many cubes could you fit into a room?

Anyone shopping for an air purifier also needs to look for two acronyms and terms. First, look for CARB certification, which means that that unit passed the rigorous standards of the California Air Resources Board. Next, check the filter type (broken down below). Also, don’t forget to unwrap your filter! There’s a special kind of horror that comes with realizing you’ve been running your air purifier with a plastic-wrapped HEPA filter.

HEPA Filters: This is a high-efficiency particulate air filter that can remove at least 99.97 percent of dust, mold, pollen, bacteria, and airborne particles as small as 0.3 microns. It's a great option for those who suffer from allergies or respiratory issues, since it can help to clear out airborne particles that can trigger symptoms—like sneezing, sore throat, difficulty breathing, coughing, and more. It's worth noting, however, that HEPA filters don't remove volatile organic compounds (VOCs) from the air the way activated carbon filters do. But these are typically paired with carbon filters.

Activated Carbon: Activated carbon filters (also known as activated charcoal) are highly effective because they are very porous and have a large surface area—allowing the filters to absorb gas pollutants, odors, and VOCs. They’re best for removing fumes, smoke, and chemicals from the air. But these filters have to be replaced more often depending on the environment. For example, if there’s a wildfire in your area and the air purifier is working more intensely than usual, it’s important to replace a saturated filter to avoid toxic gases from being released back into the air.

Washable Air Filters: A few of the options I've listed in this guide come with washable prefilters in addition to a HEPA and/or activated carbon filter—which is what you'll typically find. These are the most cost-effective since you don't have to buy new ones each time you need to replace a filter. Simply remove it, scrub it with soap and water, and let it dry.

UV-C Sanitizer Filters: Ultraviolet filters use UV light to kill viruses, parasites, mold spores, and bacteria. They can't remove airborne particles, VOCs, or gas pollutants, so they're only fully effective when combined with a HEPA filter. According to the EPA, UV lights without proper lamp coatings have the potential to emit ozone. I recommend checking this list from the Association of Home Appliance Manufacturers for models that have been shown to emit little to no ozone. —Lisa Wood Shapiro

How to Check Your Air Quality

Many large states and cities are required to report the local outdoor air auality index (AQI), which was established by the EPA and measures the concentrations of major air pollutants, like ground ozone and carbon monoxide, that are regulated by the Clean Air Act. We like AirCare (iOS, Android), but your state or county may have even more localized apps.

To check if your indoor air quality stacks up, consumer monitors like the Airthings View Plus ($330) also measure carbon dioxide, temperature, and humidity, in addition to pollutants and particulate matter (PM) of various size, including the notably health-compromising PM 2.5. Need more information? Check out our complete guide to checking your air quality. —Lisa Wood Shapiro

How Did I Test Air Purifiers?

I recently took over this guide and have started a uniform testing method for each, measuring each's efficacy by using a sealed tent and smoke pellets to see how quickly each air purifier clears the pellet smoke and returns the air to healthy quality when on auto mode. I measure first visually, using a timer to measure how long it takes to clear the smoke by eye. Then I measure how long it takes for the air quality to measure back to healthy, using both my air quality monitor and the connected app or display on the air purifier machine. I then add up the time and am able to compare models with concrete data. I also use a decibel meter on my phone to calculate noise levels during sleep and auto modes, as well as at its highest setting since air purifiers can be egregiously loud on their most powerful setting.

So for each model, I take into account how long it took on auto-adjustment settings for the air to visually clear the smoke bomb, and then use the app or machine to calculate how long it takes to measure back at healthy levels. I also use each for nearly a month, moving around my house to test in different locations: when cooking on my unventilated gas stove, under my living room window that draws in a lot of building and exhaust fumes, and outside my cat's litter box, measuring if and when the air purifier auto-engages and how long it takes to get back to clean air quality.

How Do WIRED Editors Select Air Purifiers to Review?

We look at popular models from all brands—both new and long established—and at all price points, taking into consideration features, size, effectiveness, and consumer popularity. Companies themselves often provide samples with the understanding that editorial coverage is not guaranteed. WIRED does earn affiliate revenue from purchases, but this does not factor into our editorial decisions.

What Do I Do With Air Purifiers After Testing?

A handful of top picks are kept around for longer-term testing, evaluation against new picks, and for use in testing auxiliary products like food dehydrators and the Plantaform indoor smart garden, but all others are donated locally, including to organizations like NYC public schools.

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