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We’ll be adding three new large-, medium-, and small-space picks to the guide, from Blueair and Clorox. Read more in “What to Look Forward To.” Commercial Air Purifier
Air purifiers are fundamentally simple machines—little more than a fan and a filter. Yet a well-designed purifier can capture virtually all airborne allergens, such as pollen and mold spores, as well as bacteria, viruses, and smoke.
We’ve tested more than 50 air purifiers in the past nine years, and our measurements have proved that the exceptional Coway Airmega AP-1512HH Mighty is the best among them. It’s powerful enough to use in a large room, quiet enough to sleep near, engineered to last for years, and inexpensive enough to set up in multiple rooms.
Perfect for bedrooms, playrooms, and living rooms, this purifier is one of the highest-performing, most-durable, and most-economical models we’ve tested.
Virtually identical to our top pick on features and performance, this purifier is a great choice if you prefer its looks or find it at a better price.
This purifier is terrific overall, but it has minor shortcomings, such as a stark look, no display shutoff, and slightly elevated electrical use.
Though exceptional in performance and appearance, the Blue Pure 311 also has elevated running costs and no display shutoff.
Top-class performance, quiet operation, and full display shutoff for better sleep earned this relative newcomer a recommendation after preliminary tests.
The Blue Pure 211+ aced our tests, and because it can move extremely high volumes of air, it suits large spaces.
In a small bedroom, dorm room, or office, the compact and affordable Levoit Core 300 performs extremely well and looks great.
Perfect for bedrooms, playrooms, and living rooms, this purifier is one of the highest-performing, most-durable, and most-economical models we’ve tested.
Within 30 minutes, the Coway Airmega AP-1512HH Mighty reduced heavy smoke pollution in a New York City office by as much as 99.6%; this is comparable to the performance of other top machines and has been consistent in multiple test spaces. We’ve pushed this machine beyond its on-paper limits in various ways—including running its filters 24/7 for two years, twice as long as recommended—and it has never wavered or weakened. This air purifier offers great value on initial and long-term costs. And its compact form, quiet operation, and display-light shutoff make it especially well suited to using in a bedroom.
Virtually identical to our top pick on features and performance, this purifier is a great choice if you prefer its looks or find it at a better price.
The Coway Airmega 200M is virtually identical to Coway’s Airmega AP-1512HH Mighty in every important respect. They’re equivalent in noise and performance measurements, their filters are interchangeable, and their similar controls allow you to shut off the display lights. The 200M has a square grille rather than a round one, but that’s the only major physical difference. If you prefer the 200M’s looks or you find it at a better price, we recommend it.
This purifier is terrific overall, but it has minor shortcomings, such as a stark look, no display shutoff, and slightly elevated electrical use.
The Winix 5500-2 is an exceptional performer on particulates air pollution: It captured as much 99.9% of the smoke in our test room in just 30 minutes on high. We prefer the Coway Airmega AP-1512HH Mighty for its lower energy consumption, smaller visual footprint, and manual display-shutoff feature. The related 5300-2 and C535 (which is exclusive to the Winix store and Walmart) lack a few of the 5500-2’s features, but they perform just as well and may be available at lower prices. We’ve had similarly strong results with every other Winix we’ve tested, including the AM80 and Wi-Fi–enabled AM90.
Though exceptional in performance and appearance, the Blue Pure 311 also has elevated running costs and no display shutoff.
The Blueair Blue Pure 311 Auto is similar in capabilities to the Coway Airmega AP-1512HH Mighty, the Coway Airmega 200M, and the Winix machines, with notably quiet performance, terrific energy efficiency, and a control panel that automatically dims after you adjust the settings. It’s also particularly attractive, with a tweed-like, washable cover in several muted colors. Two minor knocks against it: The air-quality indicator lamp, a bright blue LED, shuts off only when the unit is on its lowest setting, and the company recommends replacing the filters every six months, pushing yearly replacement costs above those of the other machines.
Top-class performance, quiet operation, and full display shutoff for better sleep earned this relative newcomer a recommendation after preliminary tests.
Levoit’s Vital 200S matched the Coway Airmega AP-1512HH Mighty in performance tests, and the two are very similar in terms of energy efficiency, noise output, and an ability to shut off the display while maintaining the fan setting of your choosing. However, the Vital 200S is a new release (January 2023), so we haven’t yet had time to long-term test it.
The Blue Pure 211+ aced our tests, and because it can move extremely high volumes of air, it suits large spaces.
The Blueair Blue Pure 211+ filters more air per hour than our other picks, making it quicker to achieve and maintain low particulate levels in large spaces up to 650 square feet, especially those with open floor plans or high ceilings. This machine’s combined up-front price and running costs are much higher than those of our other picks (totaling about $1,150 over five years), but they’re comparable to those of most other large-space purifiers. In our testing, the Blue Pure 211+ was an exceptional performer, and it’s quiet and attractive.
In a small bedroom, dorm room, or office, the compact and affordable Levoit Core 300 performs extremely well and looks great.
In a space that’s about 200 square feet or less, the Levoit Core 300 is a solid, inexpensive purifier. It performed impressively in our tests: On its high setting, it reduced particulates in a 135-square-foot New York City office by more than 97% in 30 minutes. On medium, it reduced them by more than 92%. It’s attractive and compact, measuring just 14.5 inches tall and 8.5 inches in diameter. It’s the cheapest up front of all our picks, and it includes a display shutoff feature. But it’s not terribly energy-efficient, and in larger rooms, it doesn’t keep pace with our other picks.
Below, we cover a few other purifiers that fit specific needs, including a purifier for handling VOCs, an especially energy-efficient small-space purifier, and a truly smart air purifier.
Since 2017, I have conducted extensive reporting on and real-world testing of air purifiers in my New York City apartment and in Wirecutter’s New York and Los Angeles offices. I have spoken with manufacturers, engineers, academics, and experts. And I have also lived with most of our picks, running them 24/7 for months—and sometimes years—in my apartment. That experience has helped me gather objective data on their long-term purifying performance and any mechanical degradation. It has also helped me make informed judgments on factors such as ease of maintenance and operation, the presence or lack of distracting noises or lights, and simple visual impact—the so-called little things that, if done incorrectly, can turn what should be a nearly set-it-and-forget-it appliance into a daily annoyance.
If you suffer from allergies or simply have concerns about the air quality in your home, a HEPA air purifier can help. These devices do just one thing, but they do it very well: remove fine particles from the air. They rapidly and permanently capture most common airborne allergens, including dust and pollen; mold, mildew, and fungal spores; pet dander; and dust mites and their excrement. They’re also excellent at reducing smoke from wildfires, tobacco, and marijuana. They also capture airborne pathogens—bacteria as well as most, if not all, viruses, including the coronavirus. These machines are pretty easy to live with, but for the full story, read this piece on How to Set Up an Air Purifier.
Once particulate matter settles on floors or other surfaces, an air purifier won’t lift it up. To clean allergens like pet hair and pollen from surfaces, you need a vacuum cleaner or a dust mop. To reduce viruses and bacteria on surfaces, it is usually sufficient to clean them with soap, detergent, or an all-purpose cleaner.
HEPA air purifiers, such as our picks from Coway and Airmega, are excellent at filtering wildfire smoke from your home’s air.
Air purifiers generally fall into three categories: those designed for small spaces (such as kids’ bedrooms, dorm rooms, and offices), those intended for general living spaces (such as enclosed living rooms and master bedrooms), and those designed for large spaces (including combined living/dining rooms and areas with cathedral ceilings).
The problem is that many manufacturers dramatically overstate their machines’ abilities. A lot of “living room” purifiers are barely powerful enough to keep a walk-in closet clear.
We begin by calculating projected airflow abilities. When considering a new purifier, we first refer to manufacturer-supplied specs on airflow (usually given as a clean air delivery rate, or CADR). We compute the air changes per hour, or ACH, they can provide in hypothetical rooms of 150, 350, and 500 square feet (assuming an 8-foot ceiling height).
We set four ACH as the minimum for a purifier to be considered adequate for each room size. Based on our years of real-world testing, we know that four ACH ensures rapid and nearly complete cleaning of highly polluted air.
We usually choose purifiers with true HEPA filters. In the North American definition, “true HEPA” means that a filter removes at least 99.97% of airborne particles of a 0.3-micron diameter in a single pass. For reference, human hair usually measures between 20 and 180 microns across. A particle with a 0.3-micron diameter is the toughest size to remove via physical, HEPA-type filtration. So both larger and—counterintuitively—smaller particles are captured more efficiently.
The European true HEPA equivalent—which is increasingly marketed in North America as “medical grade”—is designated H13, and its requirements are virtually identical: 99.95% single-pass capture of the most penetrating particle size (or MPPS). This is typically close to 0.3 micron.
We weigh the value a purifier offers. Without setting a strict price limit within each room-size category, we compare cost against specs (especially ACH), the estimated upkeep and electricity costs over the course of five years of operation, ratings from owners, and manufacturers’ histories of reliability and customer service.
Smart features are nice but not usually essential. We do not heavily prioritize smart features. Years of testing have proved that a good air purifier creates and maintains excellent air quality when it is simply allowed to run continuously on a moderate setting. However, we do note models that have smart options. The ability to control a purifier remotely or by voice command may be especially helpful for some people. Some models can offer current information about indoor air quality, and we can understand the appeal of that.
No thanks, ionizers and ozone. Many purifiers have an ionizer in addition to a HEPA filter, but we don’t look for that feature. Its efficacy is uncertain. Most purifiers with an ionizer let you toggle the feature on or off. We recommend keeping it off. One reason: The ionizers found on many HEPA purifiers can produce a tiny amount of ozone as a by-product. Among our picks with an ionizing function—as certified by the strict California Air Resources Board—none of them exceed their limit of 0.05 pars per million. Other air purifiers rely on ozone (O3) to purify the air. We dismiss those. Even low levels of ozone can be harmful (PDF).
The tools: Since 2016, we’ve conducted dozens of real-world purifier tests, measuring particle concentrations with a TSI AeroTrak 9306—a professional, high-precision particle counter commonly used to certify air quality to OSHA standards in factories and other workplaces.
The venues: We’ve tested air purifiers in homes and in apartments. And, since 2020, we’ve been testing in a room within Wirecutter’s New York City headquarters. It’s a 135-square-foot office.
The tests: At the start of each test, we take a baseline reading of the ambient air quality for three minutes. We burn five wooden matches and let the smoke circulate for two minutes to raise the particulate levels in the air. We then run the purifiers for the remaining 30 minutes.
Why use smoke? Smoke particles are right in that 0.3-micron size range (the hardest to capture). That’s why smoke is also the HEPA test standard. If a purifier does well on smoke, it will do even better on larger particles (including dust and pollen) and—somewhat paradoxically—smaller particles (like viruses). For an explanation, see How HEPA Filters Work.
We place the purifiers at the midpoint of the test room (this is best practice in your room, too). The particle counter goes in the farthest corner of the room, ensuring an accurate reading of whole-room purification. The particle counter takes readings continuously, with counts totaled in one-minute increments.
We test each purifier at least twice. In a 35-minute test, we run the machine on its absolute highest setting. It’s usually noisy. In a separate test, we use the highest setting the machine can run while keeping the noise below 50 decibels; this is around the upper limit of what would be tolerable for normal conversation, watching TV, or sleeping.
We normalize the test data so that each machine’s peak reading of 0.3-micron particles represents the maximum particulate load it faced. We describe its overall performance as its maximum reduction of particulates relative to that load. We believe this approach gives the best apples-to-apples comparison because it eliminates inconsistencies in absolute particle concentration—which even in lab conditions is difficult to reproduce exactly from test to test—in favor of a common measure.
We test new and old machines. When retesting our existing air-purifier picks, we take four measurements—two using the old filters and two using new filters—to learn how (or if) their performance changed over time.
We also make subjective evaluations. We have always judged purifiers not just by how well they perform but also by how easy it will be to live with them in your bedroom, living room, or office. For those factors, we measure how much noise the purifiers make when running, and we calculate their long-term costs for energy consumption and replacement filters. We consider the ease of operation and maintenance, the presence or absence of distracting lights (which can disrupt sleep), the simplicity of the controls, and their physical size and aesthetics.
And we simply live with them. We station our picks in multiple homes, often for years at a time, to judge how they perform in different environments, how durable they are against rowdy kids and other sources of damage, and the positive aspects (or annoyances) that are revealed as time goes by.
Perfect for bedrooms, playrooms, and living rooms, this purifier is one of the highest-performing, most-durable, and most-economical models we’ve tested.
After over 20 rounds of testing, encompassing more than 50 different air purifiers, and after years of living with our various picks at home, the Coway Airmega AP-1512HH Mighty remains our pick as the best air purifier for most people. It has kept its place since 2015 for many reasons.
It’s a stellar performer. Across repeated testing and re-testing, the Coway Mighty has delivered some of the best performances of any purifier we’ve seen, and it has done so with amazing consistency. On its high setting, it averages more than 99% removal of smoke in 30 minutes. On medium, it averages 88%. And it maintains that performance for the entire lifespan of its HEPA filter, which should be replaced annually. We’ve always run our test units 24/7 for at least a year—in one case, for two years—and then retested them using the old filters and compared them with brand-new ones. In every case, there’s been virtually no drop-off in performance for this purifier. (Occasionally, we’ve even seen a tiny improvement: HEPA filters actually get more efficient at capturing particles as they clog up, at the expense of a small drop in airflow.)
It abides. Our first test unit ran for two years straight and was performing like new when it was discontinued for a newer version. The second one ran for four years straight, and it too was still working flawlessly when it was replaced (again due to discontinuation amid Coway design updates). That third model ran at our office for over two years straight while it was closed for the pandemic, during which time the office endured a small flood. The purifier was still working fine when we reopened.
It’s virtually set-and-forget. The Mighty requires very little setup and upkeep. Remove the plastic bag the filters come in, stick the filters back in the machine, and you’re ready to go. We recommend keeping the machine on the medium setting, which is quiet, energy-efficient, and effective: In past tests, we confirmed that in a room with windows and doors closed, this purifier will drop particulate levels to nearly zero within an hour and maintain that indefinitely.
It’s quiet. For a purifier of its capabilities, the Mighty is notably quiet. On medium (the speed we recommend you run it on), it measures just 39 decibels from a distance of 6 feet—a soft, fan-like whisper that’s easy to sleep or watch TV near. (Another argument for keeping it on medium is that its auto setting can rev up the fan to its highest—and much louder—speed without warning; this is true of all purifiers with an auto function.)
It goes dark. The Mighty has a feature that we’d like to see on all air purifiers: You can completely shut off its display while keeping it on the fan speed of your choosing. Purifier displays in general are overly bright, especially their air-quality indicator lamps, and if you’re sensitive to light when you’re trying to sleep, that’s a real aggravation. Many do now offer a sleep mode that (mostly) shuts off the display.
It stands up to punishment. Parents on our staff who own a Mighty report that it has stood up to toddlers banging on the control panel and older kids roughhousing with it. Senior editor Harry Sawyers said his boys discovered that it’s fun to throw balloons into the airflow (they can get stuck and hover midair) and to use it to inflate their T-shirts so they look like the Stay Puft Marshmallow Man.)
It excels in air-quality emergencies, like wildfires. In 2017, we created wildfire conditions in our Los Angeles office and tested several purifiers. Using bunches of incense sticks, we created a thick haze of smoke in the room—which was four times larger than what the Coway is designed to be used in. It still dropped the pollution by 70% in under an hour, performing as well as some purifiers intended for extra-large spaces.
Operating costs are low. Running costs for the Mighty are easily the lowest we’ve found for a purifier of its abilities. Filter replacement is an annual task, whereas some competitors work on six- or eight-month cycles. And it’s energy-efficient: On the medium setting, it draws just 8.1 watts, so running it 24/7 on that setting consumes just 71 kilowatts annually. If you want to calculate that consumption as a dollar amount, the US Energy Information Administration lists up-to-date electricity rates by state.
Some units had fan issues (but they seem to be resolved). In early fall 2020, a few reader comments and reviews showed up mentioning an imbalanced fan in the machine, which caused the whole unit to shake uncontrollably and, in some cases, led the fan to break. We asked Coway about this problem, and a spokesperson replied that Coway was aware of the issue and was working on strengthening the fans’ balancing mechanism. As of late 2022, the issue seems to be resolved, based on recent customer reviews.
Filter odors noted (also resolved). Around the same time, we saw complaints of a plasticky odor in new replacement filters. When asked for an explanation in February 2021, Coway representatives wrote: “The filter is manufactured by processing various polymer materials … and similar to new clothes, some initial odors may linger.” The reps added that the company “is currently considering adding an Air Blow process into production to minimize any potential smell and odors.”
Two Coway filters that we purchased in February 2021 had a slight odor, and filters that arrived new in 2022 had no noticeable odor at all. Most recent (2023) Amazon reviews that mention odor describe it as faint and dissipating within a day or two.
We tested two popular third-party replacement-filter sets for the Mighty, made by Cabiclean and Durabasics, and neither gave off any noticeable odor. They performed almost identically to the genuine Coway filter in our smoke tests, so we’re confident in recommending them. One caveat: Coway told us that “if a problem is identified using a third-party filter, the customer does not receive warranty service.”
You might skip the app. We tested the smart version of the Coway Airmega AP-1512HH Mighty, the Airmega AP-1512HHS. The app is basic, but it does allow you to monitor and control your machine remotely. In evaluating the app, Thorin Klosowski, then Wirecutter’s editor of privacy and security coverage, found that “the apps have terrible customer reviews and asked for several unnecessary permissions we weren’t comfortable granting, including access to location, the camera, and more.”
Virtually identical to our top pick on features and performance, this purifier is a great choice if you prefer its looks or find it at a better price.
The Coway Airmega 200M is virtually identical to our top pick, the Coway Airmega AP-1512HH Mighty. The units are made by the same company, and they are physically so similar that their faceplates and filters are interchangeable. The 200M has a slightly more powerful motor, which may account for its marginally better performance in our tests: Running on its highest setting for half an hour, it reduced particulates by 99.4% on new filters (versus the Mighty’s 98.9%) and by 99.1% on old filters (versus the Mighty’s 98.9%). These differences are so small as to be functionally meaningless. So if you prefer the looks of the 200M, or you find it for a lower price, you can buy with confidence.
The 200M shares the Mighty’s display-shutoff feature, which we value highly because it turns off the overly bright air-quality indicator lamp and makes the 200M much more conducive to bedroom use. Visually, the 200M differs from the Mighty in that it has a square grille instead of a round aperture; like the Mighty, it’s available in both black and white versions. Previously, we dismissed the 200M because it was significantly more expensive than the Mighty, but the prices have evened up recently. We highly recommend both models.
This purifier is terrific overall, but it has minor shortcomings, such as a stark look, no display shutoff, and slightly elevated electrical use.
The venerable Winix 5500-2 performed just as well as the Coway Mighty in our testing. Both machines are similarly quiet, and the 5500-2 often sells for a bit less than the Mighty. It’s not our top pick for several reasons: It’s larger and (to most eyes) not as attractive; it lacks a display-shutoff feature, except when it’s on its lowest fan setting; and it draws more electricity, contributing to slightly higher running costs. But, simply put, the 5500-2 is an impressive purifier, and several Wirecutter staffers have happily owned this model for years.
In fact, all of the Winix purifiers we’ve tested have been impressive. If you can’t find the 5500-2, the Winix 5300-2 is identical in all important respects, though it lacks the remote control the 5500-2 comes with. The same goes for the Winix C535; this one is available only from Walmart and directly from Winix, but it often sells for less than the 5500-2 and comes with a two-year supply of filters. Finally, the AM80 and the Wi-Fi–enabled AM90 are standout performers, and they offer a sleeker, more-modern look.
Though exceptional in performance and appearance, the Blue Pure 311 also has elevated running costs and no display shutoff.
The Blueair Blue Pure 311 Auto is another stellar air purifier. It’s from the same company that makes our large-space pick. And it uses the same technology, combining a non-HEPA (but very efficient) filter with a system that imparts an electrical charge to any particles that pass through, helping them stick to the filter the next time around (essentially through static cling). In our tests, on high, this purifier reduced a heavy load of 0.3-micron smoke particles by 99.9% in 30 minutes; on medium, it reduced them by 94.2%. That puts it in the same league as the Coway Mighty and our Winix picks.
It’s an attractive machine, too, with a simple cylindrical form and a tweed-like fabric covering (which also acts as a prefilter). It comes standard with a gray covering; several other colors, “inspired by the natural landscapes of Scandinavia,” are available separately.
The Blue Pure 311 Auto also stands out for its energy efficiency, drawing just 5.9 watts on the medium setting we recommend for daily use—even less than the Mighty’s 8.1 watts. And it’s especially quiet on that setting, emitting just 33 decibels (versus the Mighty’s 39 decibels) at a distance of 6 feet; that’s almost inaudible.
A couple of caveats about the Blue Pure 311 Auto. One, its bright blue air-quality indicator lamp shuts off only when you set the fan to low. We wish it gave you the option of shutting it off on every setting, as you can do with the Coway Mighty. And two, it’s more sensitive to filter life than some other purifiers: We’ve measured fairly significant drop-offs when testing year-old filters. Blueair recommends replacing the filter “every six months or so,” and it’s best to stick to that schedule.
Top-class performance, quiet operation, and full display shutoff for better sleep earned this relative newcomer a recommendation after preliminary tests.
The Levoit Vital 200S is another excellent purifier, and it’s the most similar to the Coway Mighty in both ability and livability. It excelled in our smoke tests, and it resembles the Mighty in energy usage and noise output (meaning it’s highly efficient and very quiet on its lower, everyday fan settings). There are four fan speeds to choose from (versus the Mighty’s three), so it offers a bit more flexibility. However, the medium-high setting approaches our 50-decibel limit on acceptable noise, so it’s not clear that this is a meaningful advantage.
Most important, the Vital 200S has a display shutoff that’s independent of the fan settings, so you can darken it at night while still keeping your air well cleaned. We will conduct long-term tests of the machine to uncover any potential problems or annoyances. But based on our initial findings, this is a very promising purifier.
The Blue Pure 211+ aced our tests, and because it can move extremely high volumes of air, it suits large spaces.
If you need to purify the air in a seriously large space, we recommend the Blueair Blue Pure 211+. It’s extremely powerful, delivering our recommended four ACH (air changes per hour) in spaces as large as 650 square feet (assuming an 8-foot ceiling). That means it can clean the combined living areas of many open-floor-plan homes. It’s also an attractive, quiet-running machine, so it’s easy to live with. The five-year cost of ownership (about $1,150, including the up-front cost and the annual cost of electricity and replacement filters) is comparable to that of most large-space purifiers. The similar Blue Pure 211+ Auto is slightly more powerful (not in a way that is likely to make a meaningful difference), yet it is also more energy-efficient, due to a new motor and filter, and it adds an auto setting that adjusts the fan speed to changing air-quality conditions. We are confident that it will deliver similar, excellent performance.
In just 30 minutes, the Blue Pure 211+ reduced a heavy load of 0.3-micron smoke particles by 99.3% and 98.4% on high and quiet/medium, respectively, with filters that had seen eight months of 24/7 use. With new filters, it reduced particles by 99.3% and 99.2%, respectively. A year later, with those same filters—far past their recommended six-month replacement schedule—the numbers barely dropped, reaching 99.1% and 98.0%, respectively. Those results make the Blue Pure 211+ one of the most efficient air purifiers we’ve tested, as well as one of the most consistent on different settings. And the fact that it maintained its high performance even on significantly overused filters gives us confidence in its long-term performance.
Two slight negatives: When the 211+ is running, its on/off button emits a glow that you can’t turn off. So if, like me, you’re bothered by lights when trying to sleep, that can be an annoyance. And on the everyday, medium fan setting, the Blue Pure 211+ draws a lot more power than the Coway Mighty, consuming 46.8 watts versus 8.1 watts. That’s 33 kWh per month, versus 6 kWh. If you’re using a Blue Pure 211+ to purify a space that the Mighty or our other picks above can handle, that’s a lot of wasted electricity.
In a small bedroom, dorm room, or office, the compact and affordable Levoit Core 300 performs extremely well and looks great.
Our budget pick, the Levoit Core 300, is meant for smaller bedrooms or offices—about 200 square feet or less. In such spaces, it performs impressively. In our 2020 test, it reduced a heavy load of smoke in our 135-square-foot test space by 97.4% in half an hour on high and 92.6% on medium. Capable of 6.75 air changes per hour in a bedroom-size, 150-square-foot space, it far exceeds our four ACH minimum. And with a typical up-front cost of $100, it’s the cheapest of our picks to buy—but it’s not especially energy-efficient. That aside, it’s a compact, attractive machine, and its display-shutoff feature (which turns off the bright LED control panel) makes it especially suited for use in bedrooms.
On the high setting (which we measured at 54.1 decibels—too loud for sleep and far above our 50-decibel limit for comfortable conversation), the Core 300 reduced particulates in our 135-square-foot New York test room by 97.4% in 30 minutes. On medium, where it produced a sleep-friendly 43.2 decibels, it achieved an impressive 92.6% reduction.
The Core 300 is quite small, at 14.5 inches tall and 8.5 inches wide, so it fits on a bedside table or the corner of a desk. On its medium and low speeds, it’s quiet enough that you can sleep or converse near it. You can shut off the display so that it emits no light (a feature it shares with the Coway Mighty); this makes it much easier to sleep near. The Core 300 also features a separate sleep mode; in this mode it produces almost undetectable levels of noise—but it also moves so little air that we doubt it does much for purification.
However, the Core 300 draws 34.6 watts on medium and 31.8 watts on low, while the much more powerful Coway Mighty draws just 8.1 watts. The filters also need to be replaced every eight months. So over five years, the Core 300’s running costs may be as much as 1.5 times those of a machine like the Mighty. That still may feel manageable, and the Core 300’s low up-front purchase price is easier to swallow than those of most of our other picks. To clean the air in a small space—a bedroom, an office, or a dorm room up to about 200 square feet—it’s a solid choice.
If you specifically need to address high levels of volatile organic compounds (VOCs), we recommend the Austin Air HealthMate HM400. Like our other picks, it uses a HEPA filter to capture particulate pollutants. But it also contains a massive, 15-pound adsorbent filter (composed of activated carbon and a class of mineral called zeolites) that efficiently captures gaseous pollutants such as formaldehyde. That said, in most parts of the country, simply opening your windows every few days is an effective way to flush out any VOCs.
The Blueair Blue Pure 411 series encompasses three similar models: the original Blue Pure 411 (a former pick for small spaces), the Blue Pure 411 Auto, and the Blue Pure 411+.
In our testing, the machines did not match the rapid air cleaning of our current small-space pick, the Levoit Core 300. But they did well compared with other small-space machines we looked at, averaging about 85% removal of smoke particles in 30 minutes on high and about 65% in 30 minutes on medium, in a 200-square-foot room. Over a longer timeframe—and especially if kept running on medium 24/7, as we recommend for all our purifier picks—they will create and maintain very clean air in a typical home office or bedroom. And they are incredibly energy-efficient: On medium, running around the clock, they consume only about $6 worth of electricity per year.
The Mila air purifier is a notable entrant in the nascent category of truly smart air purifiers. When we tested it in October 2020, it delivered excellent performance on smoke particles, virtually identical to the performance we got from the Coway Mighty. Compared with the features of other smart air purifiers we’ve looked at, its app, sensors, and programmability are head and shoulders more advanced—almost another species. Although we believe that most people are likely to be happy with a purely analog purifier, if you’re keen on smart appliances, then this model is worth considering.
We tested the Coway Airmega Icon purifier in April 2020. It’s an interesting machine, straddling the line between appliance and furniture, and it incorporates a second function: It has a built-in, 20-watt wireless device charger. This model performed exceptionally well in our tests, removing 99.6% and 97.4% of smoke particles in 30 minutes on high and medium, respectively. It’s also notably quiet on its low and medium settings, where it would normally be running, putting out 33 and 43 decibels, respectively. And the charger worked flawlessly on the iPhone we tested it with.
The Coway Airmega 240 has no unique abilities; it’s for those seeking a terrific-looking, high-performing, and well-priced air purifier. As purifiers become standard appliances in more and more homes, manufacturers are increasingly designing truly attractive machines. But in many cases, these good-looking models are priced significantly above—sometimes hundreds of dollars above—more-utilitarian, often more-capable purifiers. The Coway Airmega 240 performs nearly as well as our top-pick Coway Mighty and usually costs only a bit more (about $50).
After a round of testing in October 2023, we will be replacing two of our picks from Blueair, the Blue Pure 211+ and Blue Pure 311 Auto, with their kindred models from the company’s newer Max line.
The Blue Pure 211i Max, meant for large spaces above 500 square feet, is a stellar performer, reducing smoke levels in our test room by more than 99.9 percent on its high and high-medium settings. And it has a couple liveability features that we value: You can shut off the display while maintaining your desired fan-speed—a real boon if you’re light-sensitive while trying to sleep—and you can lock the controls so children can’t accidentally change the settings while roughhousing. It also has an an air quality sensor that lets you read your room’s particulate-pollution levels at 1, 2.5, and 10 microns (a.k.a. PM1, PM2.5, and PM10, broadly equivalent to smoke, dust, and pollen).
The Blue Pure 311i Max, whose lower airflow is meant for medium-sized spaces up to about 400 square feet, reduced smoke levels by 99.9% and 99.7% on high and medium and also has a display shutoff and child lock, but lacks the 211i Max’s particulate display. Both are exceptionally energy efficient thanks to re-engineered motors, enlarged air intakes, and more-open outlet grilles, and both can be monitored and controlled manually or via the Blueair app.
Lastly, we’ll be replacing our current small-space/budget pick, the Levoit Core 300, with the Clorox Medium Room. (That’s a misnomer: It’s decidedly an office or bedroom machine, not one that’ll handle a living room or open floorplan area.) A great performer, it’s also quieter and more energy efficient than the Levoit, and has a display shutoff, child lock function, and Alexa compatibility.
To get the most out of an air purifier, you need to set it up correctly, operate it properly, and perform very occasional maintenance. Here’s a list of what to do:
Remove the wrappers. Most air purifiers arrive with the filters installed—but they are also sealed in plastic wrappers. Open up your machine, unwrap the filters, and reinstall them. The HEPA filters should have an arrow or other marking to indicate the correct orientation.
Place them correctly. Install your purifier at least 18 inches from a wall and any furniture, ideally near the midpoint of the room you’re using it in.
One purifier per room is best. Purifiers work best in a contiguous space; if you want to clean the air in both the living room and a bedroom, for example, it’s best to get a purifier for each room or to move a single purifier around with you.
Oversized is okay. It’s better to have “too much purifier” than not enough. Manufacturers typically base their room-size recommendations (and CADR ratings) on tests with the machines set on high. But high is usually too loud when you’re watching TV or sleeping. Purifiers rated for larger spaces can operate on lower, quieter speeds.
Keep it running. Under typical conditions, we recommend running air purifiers 24/7 on their highest “quiet” setting—which we define as 50 decibels (dBA) or less. That generally means the medium setting on three-speed purifiers, or the high-medium setting on four-speed machines. Under known bad-air conditions, such as during a nearby wildfire, we recommend running purifiers on high for an hour every so often to deep-clean the air.
Close doors and windows. A draft or an open door can draw unfiltered air into a room faster than the purifier can deal with it. Normal in-and-out foot traffic isn’t an issue; just close the door behind you.
Clean the prefilter monthly. For optimal performance, vacuum, wipe down, or rinse off the prefilter (it looks like a window screen or plastic netting) every month or so. The prefilter catches larger particles, such as pet hair, and keeping it clean helps the HEPA filter work unimpeded on fine particles.
Schedule filter replacement. It’s easy to forget the occasional obligation of replacing your purifier’s filters—so set a calendar reminder. Purifier manufacturers typically recommend replacing them annually, but check the manual; some models call for less frequent or more frequent replacement.
In conditions where air quality is poor, like when your area is affected by a nearby wildfire, we recommend running air purifiers on high for an hour and thereafter running them on the quiet or medium setting to create and maintain clean air in the home. After burning 15 wooden matches (to create an initial heavy load of fine smoke particulates), we tested this method with the Coway Airmega AP-1512HH Mighty and the Airmega 400 over the course of three hours—one hour on high, followed by two on medium.
Set on high, the AP-1512HH reduced the particulate concentration by 99.9% in the first hour. With the purifier set on medium over the next two hours, the particulate load remained stable, varying no more than 0.1%. In the first hour on high, the Airmega 400 also reduced the particulate concentration by 99.9%, and thereafter the particulate load varied by no more than 0.2% on medium. In these tests, the purifiers handled normal ambient air after we raised the smoke levels at the outset.
In a separate, similar test, we fed the purifiers continuously smoky air by burning incense sticks throughout the test. This test also included the Coway AP-1512HH Mighty, compared against a former large-space pick, the Blueair Blue Pure 211+. In that test, we learned we had to run the machines on high to maintain meaningful purification. Both models achieved this, cutting the particulates by half or more in 50 minutes.
HEPA stands for “high-efficiency particulate air.” The filter technology is the result of an industrial need that became critical in the Atomic Age: high volumes of very clean air, vital for the production of microprocessors and other sensitive instruments. HEPA filtration is also fundamentally simple and cheap, which means it’s available to everyone today.
HEPA filtration is a physical process, but it’s not like what most people envision when they think of a filter: a net, or a colander, or maybe mosquito netting, where particles larger than the holes get caught and the rest passes through. Rather, in HEPA purifiers, a fan draws particles suspended in the air through a dense, felt-like filter that has billions of tiny gaps of varying size. Air passes through almost unimpeded—thus the “high-efficiency” in HEPA. But the maze-like web of fibers traps almost all of the particles, from relatively big material like pollen (10 microns or so) down to ultrafine, 0.01-micron (10 nanometers) stuff. That’s smaller than an individual virus.
The fibers in a HEPA filter capture airborne particulates in three basic ways (PDF).
Impaction: The largest of the particulates, about 0.5 micron and above, are captured via impaction: Unable to change their course due to momentum, the particulates simply slam into the fibers and stick to them.
Interception: Particles measuring less than 0.5 micron (but not too much less) are captured by interception: Their lower momentum allows them to flow around some fibers, but eventually they come close enough to touch one fiber on the way by, and again they stick.
Diffusion: Very fine particles measuring below 0.1 micron get bounced around randomly and are slowed by their interactions with atmospheric atoms and molecules. They eventually drift or get bounced into a filter fiber, whereupon (yet again) they stick in a process called diffusion.
Crucially, the hardest particles to capture are what you might call the Baby Bears: At 0.3 micron, they’re at the low limit of interception momentum and above the limit of diffusion—in other words, they’re “just right” to get through a HEPA filter. The solution is to make the filter dense enough that it has a sufficient amount of fibers to capture most of the 0.3-micron particles. According to the US HEPA standard, “most of them” means 99.97% of them in a single pass.
Let’s begin by defining what the IKEA Förnuftig is not: It is neither a true-HEPA purifier nor an especially powerful purifier, period. It’s designed to capture PM2.5—particles 2.5 microns in diameter and above, in contrast with the 0.3-micron HEPA standard. That means it’s optimized for larger airborne particles, such as pollen and mold spores, rather than for very fine particulates, like wildfire smoke (as HEPA filters are).
An IKEA representative told us that “this is a deliberate design consideration, to find the right balance between affordability, small form factor for high home furnishing appeal and low energy consumption, while retaining a comparably high airflow and CADR.” Fair enough, but with a clean air delivery rate (CADR) of just 82.4 cubic feet per minute, the Förnuftig is appropriate only for very small rooms, no more than 125 square feet (and IKEA suggests just 100 square feet, a 10-by-10-foot space). In short, it’s cheap, sleek—and weak. We don’t recommend it.
We tested the Förnuftig in a 200-square-foot spare room, using the methods described above. But rather than focusing on its performance on 0.3-micron particles, we noted how well it removed 3-micron particles from the air. (IKEA confirmed that this was the appropriate size to look at; it’s the closest to PM2.5 that our TSI AeroTrak particle counter can measure separately.)
The Förnuftig disappointed—even when we considered that the test room was larger than the space the machine is meant for—because it removed just 85.2% of 3-micron particles in 30 minutes on high and 73.6% in 30 minutes on medium. Its performance on 0.3-micron particles was, as expected, worse: 64.5% removed on high and 53.5% on medium. Compared with our budget/small-space pick, the Levoit Core 300—which removed 97.4% and 92.6%, respectively, of 0.3-micron particles and removed virtually all 3-micron particles on the same settings—that’s very poor.
In 2019, we purchased a Molekule Air—the company’s iconic original purifier—and found it to be the worst air purifier we’ve ever tested. Its performance on particulate pollution was dismal—and absolutely unacceptable for an $800 device. We later learned that many of the company’s advertising claims were found to be baseless, and Molekule subsequently retracted almost all of them. (You can read about the saga in our reports from February and June 2020; the Air was then known as the MH1.) That year we also tested a Molekule Air Mini and judged it to be similarly poor.
But both of those models have been retired, so in January 2023 we purchased and tested the company’s current models, the Molekule Air Pro and the Moleklule Air Mini+. In addition to a HEPA filter, the Air Pro and the Mini+ employ the company’s patented PECO technology, which Molekule claims not only captures pollutants like smoke, bacteria, and viruses—as HEPA filters do—but also destroys them using a UV-based reaction.
The Air Pro is Molekule’s larger purifier. Molekule’s specs claim it is effective in spaces as large as 1,000 square feet. In our testing, it did do something the original Air didn’t: effectively remove fine particles from the atmosphere. On its highest setting, it dropped the smoke levels by 99.9% in 30 minutes—as good a performance as any purifier we’ve tested. Molekule does not share the actual numbers, but presuming the claimed “3x” airflow refers to the original Air’s 90 cubic feet per minute, the Air Pro’s maximum airflow rate would be about 270 cfm, slightly higher than that of the top-pick Coway AP-1512HH Mighty.
But there’s a deal-breaking caveat. On that setting, the Air Pro emitted an earsplitting 71 decibels, measured from a distance of 6 feet. That’s by far the loudest of any purifier we’ve tested, and it would be absolutely unlivable in real-world use. I could hear its jet-like whine from 40 feet away, and it was on the other side of a heavy, acoustically sealed door. For reference, we set the limit of comfort at 50 decibels, and humans perceive a 10-decibel increase as roughly a doubling of loudness. So the Air Pro is effectively four times noisier than what we consider to be acceptable.
At its highest sub-50-decibel setting (which was speed three out of six), the Air Pro performed similarly to our top-pick Coway on its medium setting, removing 86.1% of the smoke particles we’d filled our test space with in 30 minutes. But it was louder, at 43 decibels, versus the Coway’s 39.
The Air Pro is a power hog, drawing 27 watts on speed three—more than three times what the Coway draws on medium. On its highest setting, we measured it at 111 watts (the Coway draws 68 on high), and Molekule actually lists a bigger number on the Air Pro’s spec sheet: 123 watts.
The many critical reviews on Molekule’s Amazon store frequently mention noise, an unpleasant smell (we didn’t notice it), difficulty connecting to Wi-Fi and the app, and cost. It typically retails for $1,000, and replacement filters are $160. If you kept up with the recommended six-month filter replacements, you’d spend $1,440 over the course of five years. Add the cost of electricity and the purchase price, and you’d spend well over $2,500 on a machine that performs no better on particulate pollution than the far less expensive purifiers we recommend.
The Molekule Air Mini+ is designed for small spaces, like a bedroom or home office. In our testing, it performed far worse than our pick for those scenarios, the Levoit Core 300—which costs about $100, versus the Air Mini+’s typical $350 or more. On its medium setting (speed three, out of five), the Air Mini+ reduced smoke levels by just 58.7%, versus the Levoit’s 92.6%. And even on its highest setting, at which it emitted an intolerable 66 decibels, the Air Mini+ reduced the smoke only by 91%; the Levoit captured 97.4% on high, while emitting 54 decibels. That’s a bit too loud for continuous use, but it’s less than half as loud (in terms of human perception) as the Air Mini+.
Along with its high up-front cost, the Air Mini+ is also expensive to maintain, requiring a $90 replacement filter every six months. It’s not particularly power-hungry, unlike the Air Pro. But on its medium setting, the Air Mini+ still draws more electricity than the far-more-capable Coway Mighty (our top pick among purifiers and a machine capable of keeping the air clean in a far larger space). As with its larger sibling, we do not recommend the Molekule Air Mini+.
It’s a popular claim: If you stick a furnace/HVAC filter on a standard box fan, you can make a useful DIY air purifier. To test this, we taped a 20-by-20-inch Honeywell FPR 9 filter to a 20-inch Lasko box fan, and we ran that combo through the standard 35-minute, five-match test in the 200-square-foot New York City space, with the fan on high. And you know what? It did okay, cutting the initial particulate load by 87% over 30 minutes on medium. That’s nothing like the 99% reductions our top picks achieved on their high settings, but the results were better than one might expect.
If you try this hack, carefully seal the filter around its entire perimeter with clear, pro-strength packing tape—any gap would have let unfiltered air pass through, the same as on dedicated air purifiers. Doing all this may damage the fan’s motor, and we wouldn’t consider it to be a long-term solution for air-quality issues. But if you experience an air-quality emergency—say, regional wildfires creating a purifier supply shortage—it’s worth a shot.
One other thing worth mentioning: A popular video of this hack, from the University of Michigan Health System, overstates its potential. The presenter places the particle counter directly in front of the filter—almost touching it with the sensor—and notes that virtually no particles are passing through. It’s more important to measure the effect of a filter on the overall particulate load in the room. We measure purifier performance at a distance from the machines, outside the path of the cleaned airflow.
In addition to the following models, we have reviewed and dismissed hundreds of purifiers since 2013 based on their specs, features (or lack thereof), livability, and price. Some well-known brands that have never made our cut include Alen, Bissell, IQAir, Oransi, Rabbit Air, and TruSens, generally based on their elevated up-front and running costs relative to those of our picks.
We have also removed from this list many since-discontinued models we tested.
The Dreo Macro Max S is a high-performing purifier with a major flaw: an enormous, bright air-quality indicator lamp that shuts itself off only in night mode, in which the fan is locked on its lowest, least effective setting. The lamp can be shut off at other fan speeds via the app, but, as with virtually all smart purifier apps, this one has many reports of connectivity issues. A manual shutoff option would be an improvement.
Blueair says its DustMagnet machines “powerfully attract airborne dust particles like a magnet before they settle on floors and surfaces.” But those claims refer to a certain size range of particles, from 0.5 to 3.0 micron—smaller than the human eye can see—so you’d have no way of knowing. In our testing with a professional particle counter, the Blueair DustMagnet 5440i performed no better than the much less expensive Coway Mighty.
Levoit’s Core 600S is a powerful machine designed for use in spaces up to about 700 square feet, at four air changes per hour, and it performed very well in our tests. However, on its medium-high and high speeds, it produced a persistent rattle that we could not ignore; nor could we fix the problem by repositioning the machine and confirming that the filter was properly seated.
The Honeywell InSight HPA5300B, a large-space model, likely performs well, but after measuring its electricity demands, we dismissed it. Compared with our pick for large spaces, the Blueair Blue Pure 211+, the Honeywell is a power hog, drawing 33, 60, 94, and 117 watts on its four (low to turbo) speeds, respectively. The Blue Pure 211+ tops out at 64 watts and is a slightly more powerful machine in terms of clean air delivery rate (CADR).
Honeywell’s HPA300 performed well in our tests but was also extremely loud, topping out at 62 decibels on its highest setting and measuring 53 decibels on the higher of its two medium speeds. It’s large and visually intrusive, too: a black tower that’s almost 2 feet tall, 18 inches wide, and 10 inches deep.
The Coway Airmega 150 is the first small-space machine from that company. It’s sharp-looking, with a clean rectangular form and a muted, matte finish available in several colors. But at its typical price of $190, it’s too pricey for a machine made for spaces no larger than a bedroom.
The Coway Airmega 250 is the larger, more powerful sibling of the Coway Airmega 150. It’s equally attractive, but it’s only slightly more powerful than our top pick, the Coway Airmega AP-1512HH Mighty, yet it costs $200 more.
We tested the tower-style Coway AP-1216L in 2017. Despite its decent-to-solid performance, we don’t recommend it. The small footprint of 10 by 8 inches belies the fact that it’s 32 inches tall—the height of a kitchen counter—and so it takes up a huge amount of visual space. You’d never forget that you have a purifier in the room.
The AirSoap uses washable, electrically charged plates to capture airborne particulates. Our top pick Coway Mighty performed far better in our tests. AirSoap’s claim that it will save you “thousands” in the cost of replacement filters is ridiculous—you’d have to replace the filter on the Coway Mighty 20 times to reach even $1,000, which means you’d have to run it for two decades.
The Aeris Aair 3-in-1 Pro performs similarly on particulates to our pick for large spaces, the Blueair Blue Pure 211+. And it contains a large VOC filter composed of 2.2 pounds of activated carbon and alumina, which should make it far better at capturing VOCs. But it’s expensive, the filters last only six months, and replacements cost about $200.
AirDoctor sells an expensive purifier with a filter that it markets as “UltraHEPA,” claiming that the filter traps particles 100 times smaller than what HEPA filters can capture. It’s not true: All true-HEPA filters snag virtually 100% of the nanometer-scale particles that AirDoctor says is its unique ability to capture.
We’ve tested many Dyson purifiers over the years, most recently (2019) the Pure Cool TP04 and Pure Hot+Cool HP04. Neither model measured up well against our top pick, the Coway Mighty. We have also found no evidence that the fan function on Dyson purifiers makes them superior to other purifiers in the distribution of filtered air throughout a room. In fact, our years of testing have shown that any appropriately sized purifier will deliver filtered air rapidly into the farthest corner of a room.
The Medify MA-40 performs similarly to the top-pick Coway AP-1512HH Mighty, but it’s much louder, at 52 decibels (above our 50-decibel definition of “quiet”) on its medium setting and 42 on low. The Coway measured 39 decibels and 31 decibels (nearly inaudible), respectively.
The huge and exceptionally powerful Medify MA-112 is surprisingly easy on the ears, registering as “quiet” on its low, low-medium, and high-medium speeds (39, 42, and 47 decibels). But at 28 inches tall and 15 inches wide, it’s best suited to large commercial or public spaces—like casinos, which Medify says use the MA-112 to counter the effects of cigarette smoke.
The GermGuardian AC5900WCA was a stellar performer in our 2019 test, but we also found it to be much louder than the top-pick Coway Mighty, measuring 47 decibels versus 39, on its quiet/medium setting. And the quality of the sound was rough and whooshy, versus the Mighty’s steady white noise. It’s far more expensive to maintain, as well.
The Levoit LV-H133 is another competitor to the Coway Mighty. But it’s more expensive up-front as well as over the course of five years of upkeep. And its taller form and higher noise output make it visually and audibly intrusive.
The Levoit Vista 200 is a small-space machine, and it’s one of the best-selling purifiers on Amazon. However, it’s much weaker in its CADR specs than our small-space pick, the Levoit Core 300.
A budget contender, the Levoit LV-H132 performed poorly in our tests, reducing particulates in our 200-square-foot test room by just 60% on high, in contrast with the 92.6% reduction that our small-space pick, the Levoit Core 300, achieved on medium.
Our previous top picks among large-space purifiers, the Coway Airmega 400 and Coway Airmega 300, are stellar performers. But the Blue Pure 211+, our equally capable current pick, comes out on top on price: It typically sells for several hundred dollars less. The same is true of the Coway Airmega 400S, a smart version of the 400.
Winix’s HR900 Ultimate Pet Air Purifier has lower specs than our less expensive top pick from Coway.
The Hathaspace Smart True HEPA Air Purifier has solid reviews and typically costs a bit less than the top-pick Coway Mighty. For that price, though, you get a machine that’s barely a third as capable: The Hathaspace purifier can produce, at most, two air changes per hour in a 350-square-foot room, whereas the Mighty purifier can deliver 5.7.
The GermGuardian AC4825 has been around for years and is, up front, cheap. But because of its higher energy consumption, it costs more to maintain than our current budget pick, the Levoit Core 300. And it’s a tall, garish device that won’t blend into any decor outside of an Alien set.
In addition to the above models, we looked at and dismissed multiple purifiers from the growing crowd of knockoff brands. It’s plainly a Duff Dry situation, and there’s no reason to doubt that these suspiciously similar knockoffs would perform all that differently from the originals. But we place a premium on long-standing companies with a record of customer service—and these pop-up brands lack both attributes. Rather than address them individually, we turned them into a poem, since their names (and this isn’t an exhaustive list) are quite lyrical:
This article was edited by Harry Sawyers.
Tim Heffernan is a senior staff writer focusing on air and water quality and home energy efficiency. A former writer for The Atlantic, Popular Mechanics, and other national magazines, he joined Wirecutter in 2015. He owns three bikes and zero derailleurs.
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Dehumidifier Air Purifier Wirecutter is the product recommendation service from The New York Times. Our journalists combine independent research with (occasionally) over-the-top testing so you can make quick and confident buying decisions. Whether it’s finding great products or discovering helpful advice, we’ll help you get it right (the first time).