2020 tests

At a cost of $1,000, the Aeris Aair 3-in-1 Pro is a high-end purifier—a growing category that we plan to explore in depth in the future. In addition to its HEPA filter, it contains a large VOC filter composed of 2.2 pounds of activated carbon and alumina. That should make it far better at capturing VOCs (odors and other gases) than the tiny VOC filters most purifiers contain. The HEPA filter is also treated with an antibacterial coating that, Aeris says, “reduces risks of infection when replacing filters.” (That risk is already extremely low, as HEPA filters are not a conducive environment for bacterial growth to begin with.) But while it tested well, the Aair did not perform any better on particulates than our much less expensive pick for large rooms, the Blue Pure 211+. The Aair reduced particulates by 98.1% and 94.1% on high and medium in our 30-minute tests; the 211+ achieved 99.3% and 98.4% reductions in identical conditions. Another knock on the Aair: The filters last only six months, and replacements cost $200.

2019 tests and contenders

The Blueair Blue Pure 411, our former budget pick, performed well for a small-space purifier and is exceptionally energy efficient. Running on medium 24/7, it only consumes about $6 of electricity per year. Replacement filters every six months, at $22 apiece, will cost $198 over the course of five years (nine new filters). That makes it far cheaper to own than our new top pick for small spaces, the Levoit Core 300, which may cost $480 over five years for filter replacements and electricity. However, performance is our most important measure of a purifier, and the Levoit far outperformed the Blue Pure 411. We will be testing the new, slightly more powerful Blue Pure 411+ once we have access to our New York office again.

In 2019, we tested two of Dyson’s latest-generation air purifiers, Pure Cool TP04 and Pure Hot+Cool HP04. Of them, the TP04 performed better, but neither measured up well against our top pick, the Coway AP-1512HH Mighty, and our large-space pick, the Blueair Blue Pure 211+. On its highest setting, the TP04 reduced particulate pollution by 86.6% in 30 minutes; compare that with 98.9% and 99.3% from the Mighty and the Blue Pure 211+, respectively. On medium—which we set as fan speed 6 of the 10 speeds available—the TP04 managed just 74.4% reduction. The Coway and Blueair scored 87.6% and 99.2%, respectively. The Dyson Pure Hot+Cool HP04, which incorporates a space heater as well as a purifier, in theory should have performed somewhat better than the TP04 because it can move a slightly greater volume of air. But in our tests it performed significantly worse, achieving just 77.4% and 55.1% reduction on its highest and medium (speed 6) settings, respectively. We cannot recommend either Dyson purifier, especially given their high price relative to those of our much higher-performing picks. We have also found no evidence that the machines’ fan function, as Dyson claims, 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 distribute filtered air evenly, into the farthest corner of a room.

We have not tested the Dyson Pure Hot+Cool HP06 Cryptomic purifier, but spoke at length with a Dyson engineer and representative about it. In terms of particle filtration, it is virtually identical to the Pure Hot+Cool HP04 (see preceding paragraph), using the same HEPA filter and featuring only marginally lower airflow. We would not recommend it for same reasons we do not recommend the HP04. The HP06 adds a molecular formaldehyde filter, which Dyson calls the Cryptomic.

We tested two purifiers from Medify, the MA-40 and the MA-112. The smaller Medify MA-40 has specs similar to those of our top pick, the Coway AP-1512HH Mighty, and in fact it achieved the same reduction in particulate pollutants: 98.9% on high. It’s also a good-looking and well-built appliance, with a glass touchscreen (not plastic as on most purifiers). But it’s a loud machine, measuring 52 decibels (above our 50-decibel definition of “quiet”) on its medium setting and 42 on low. For comparison, the Coway Mighty measures 39 decibels on medium and 31 decibels (nearly inaudible) on low. Typically, this Medify model also costs about $100 more than the Coway.

The huge and exceptionally powerful Medify MA-112 has the highest CADR rating we’ve ever seen: 950. (That’s almost three times more cubic feet per minute than with our large-space pick, the Blueair Blue Pure 211+.) It virtually eliminated particulates from our test room, reducing them by 99.9% on its high and medium speeds. And for such a powerful machine, the 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, respectively). But this model is physically huge, at 28 inches high and 15 wide, and it’s a rare home that has an open space big enough to demand such a powerful purifier (Medify says casinos use it to clear cigarette smoke). It has historically cost upwards of $750; we have seen it dip to near $500 at times, which is closer to being competitive with our other picks, but again: only if you really need to clean a vast space.

The GermGuardian AC5900WCA was a stellar performer in our 2019 test, reducing particulates by 99.3% on high and 98% on medium. Those results actually beat the performance of the similarly priced Coway AP-1512HH Mighty, our top pick, despite the GermGuardian’s slightly lower CADR numbers. And we like the GermGuardian’s clean looks and clever night-light feature: a small blue circular LED that glows through the machine’s seamless white faceplate. (You can turn the night-light and the display lights off if they disrupt your sleep.) But we also found it to be much louder than the Mighty, measuring 47 versus 39 decibels on its “quiet”/medium setting, and the quality of the sound was rough and whooshy, versus the Mighty’s steady white noise. This model is far more expensive to run, as well, requiring a $70 replacement filter every eight months (versus $50 once a year for the Mighty) and using about $64 versus $14 of electricity annually if run 24/7 on medium, due to its much higher energy consumption. Over five years, the GermGuardian will cost roughly $900 versus the Coway’s roughly $470. Note: The AC5900WCA is widely out of stock as of July 2020, but the company is producing more units and expects to have them available later in the summer and this fall.

The Levoit LV-H133 is another competitor to the top-pick Coway, and it produced similar test results—98.8% and 92.9% reduction in particulates on high and medium, versus 98.9% and 87.6%. But it’s more expensive up front and over the course of five years’ 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 on CADR specs than our small-space pick, the Blueair Blue Pure 411, and it produced very poor results in our tests: just 58.0% and 59.2% reduction of particulates on high and medium, respectively, versus the Blue Pure 411’s 87.2% and 70.7%.

Our previous top pick among large-space purifiers, the Coway Airmega 400, is a stellar performer, registering 99.9% and 99.7% reduction of particulates on high and medium, on both new filters and filters that had been run 24/7 for a year. Those figures slightly topped the results from our current large-space pick, the Blueair Blue Pure 211+, which came in at 99.3% and 99.2% on new filters and 99.3% and 98.4% on filters that had been run 24/7 for eight months. The two machines are similarly quiet, with the Airmega 400 registering 40 decibels on its “quiet”/high-medium setting and the Blue Pure 211+ measuring at 43 decibels on medium. But the Blue Pure 211+ came out on top in long-term costs: It typically sells for $250 versus the Airmega 400’s $450 to $550, and the Blue Pure 211+ totals about $800 over five years versus about $1,100, counting the cost of annual replacement filters and electricity.

While we were researching and writing this guide, LG discontinued its Air Purifier Tower AS401WWA1 and PuriCare Air Purifier Round Console. Some units may still be available as dead stock, but the world needn’t lament the fallen. The Tower had much lower specs than our top pick, the Coway AP-1512HH Mighty, yet it cost $400—more than twice as much. The Round Console was also weaker on specs and higher priced than the Coway, at $300.

The Inofia PM1320 claims to work in rooms as large as 800 square feet. Based on its specs, it’s appropriate for rooms of just 287 square feet (where its CADR numbers result in our recommended 4 air changes per hour).

The Pure Company’s Large Room Air Purifier usually costs $400 but has lower specs than those of our typically $175 top pick, the Coway AP-1512HH Mighty.

The Levoit LV-H134 also costs about $400 and has lower specs than the top-pick Coway.

Although the Winix FresHome P150 is similar in physical size to the Coway AP-1512HH Mighty, it has specs well below those of a small-space purifier.

Winix’s HR900 Ultimate Pet Air Purifier has far lower specs than that model and our less expensive top pick, the Coway AP-1512HH Mighty.

We find tower-style machines like the Winix NK100 to be visually intrusive. The NK100 also has lower specs than the top-pick Coway Mighty and typically costs a bit more. The otherwise identical Winix QS and Winix NK105 add dubious features (a Bluetooth speaker and Wi-Fi connectivity, respectively), and both of those models usually cost more than the Coway.

The Hathaspace Smart True HEPA Air Purifier has solid reviews and costs a bit less than the top-pick Coway. For that price, though, you get a machine that’s barely a third as capable: The Hathaspace delivers 2 air changes per hour in a 350-square-foot room, whereas the Coway delivers 5.7.

Dyson calls the Pure Cool Me BP01 a “personal purifying fan”—it’s designed to deliver a focused stream of air onto a person’s face from a bedside table or an office desk—and does not consider it a whole-room purifier, so we didn’t test it.

TruSens, a new air-purifier maker that launched in early 2019, made a splash in earning a RedDot Design Award. But only the largest model, the Z3000, is true HEPA; the smaller Z1000 and Z2000 are “HEPA-type,” which is to say, not true HEPA. And the company uses 2 air changes per hour to calculate its square-footage ratings, whereas we set 4 ACH as a minimum. TruSens doesn’t list its devices’ CADR ratings publicly, nor could its customer support team provide the ratings when we asked. When we found the CADR numbers in the manuals, we were alarmed. The Z2000 (the “medium room” model), which by TruSens’s claimed specs is a direct competitor to our top pick, the Coway AP-1512HH Mighty, has a CADR of 112/117/95 on dust/pollen/smoke—in every case less than half the Coway’s CADR ratings, and below those of even our top pick for small rooms, the Blueair Blue Pure 411. The Z1000, TruSens’s “small room” model, is even weaker. Both models also draw far more power than their supposed equivalents among our picks, and both cost the same or more up front. Finally, the manual for the “large room” Z3000 does not offer CADR numbers, but with a claimed ACH of 2 in a 750-square-foot space, it’s barely half as powerful as our large-space pick, the Blue Pure 211+ (3.5 ACH in 750 square feet). Yet it costs far more up front, with a price tag of $400 versus a usual $300 for that Blueair model.

On top of the above models, we looked at and dismissed multiple purifiers from the growing crowd of knockoff manufacturers. We are not challenging their claims, though we are skeptical of them. But we do place a premium on manufacturers of long standing, with a record of customer service—and these pop-up manufacturers lack both. Rather than address them individually, we turned them into a poem, as their names (and this isn’t an exhaustive list) are quite lyrical:

Sumgott, Koios, UNbeaten, Zibrone;

Renpho, Aviano, Mooka, Keenstone;

Partu, Geniani, KeenPure, Hauea;

Cisno, Airthereal, iTvanila, Secura.

2018 and earlier tests

In 2018, we tested two large-space contenders from Honeywell, the 50250-S and the HPA300. The 50250-S failed our noise tests, registering more than 50 decibels even on its lowest setting (50 decibels is our limit for what we consider “quiet”). It’s a popular purifier, with a design that has gone largely unchanged for years, but even many of its adherents acknowledge that noise is an issue. The HPA300 performed very 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, consisting of a black tower almost 2 feet tall, 18 inches deep, and 10 inches wide. And it’s fussy to maintain, with three small HEPA filters to replace and a prefilter that you have to Velcro in exactly the right place—otherwise it will prevent the cover from reattaching. This model typically costs only slightly less than our top pick for large spaces, the Blueair Blue Pure 211+, which is a more powerful, more attractive, and quieter machine.

We retested our former budget pick, the GermGuardian AC4825. The GermGuardian performed well, but it costs far more to maintain than our current budget pick, the Blueair Blue Pure 411, because of its huge energy consumption—52 watts on medium, versus the Blue Pure 411’s 3.6 watts.

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 to the almost 92% reduction that our small-space pick, the Blueair Blue Pure 411, achieved.

Our former runner-up, the Winix 5500-2, once again performed well in our 2018 retest. But it costs about $800 to run over the course of five years, nearly twice as much as the comparably performing top pick, the Coway AP-1512HH Mighty. We dismissed the very similar Winix 5300-2, an alternate runner-up in a previous version of this guide, for the same reason.

The Coway Airmega 300, our previous pick for large spaces, is similar in specs to the Blueair Blue Pure 211+, our current large-space pick, which typically costs about $250 less.

We tested two tower-style units in 2017, the Coway AP-1216L and the since-discontinued LG PuriCare AS401WWA1. Despite their decent-to-solid performance, we don’t recommend either one. Their small footprints (10 by 8 inches for the Coway, 11 by 11 inches for the LG) belie the fact that they’re 32 and 30 inches tall, respectively—as tall as a kitchen counter—and so they take up a huge amount of visual space. You’d never forget that you have a purifier in the room. And at about $400 up front at the time of our review, the LG in particular didn’t justify its cost.

In 2017, we also tested the Dyson Pure Hot+Cool Link HP02 for particulate performance in the lab and in our real-world New York apartment. It offers two distinct fan functions—diffuse and focused; we tested it on both functions in the lab and in the real world. John Holecek further tested the Hot+Cool Link for VOC removal in the lab, given that Dyson had implemented an upgrade of its VOC filter since our 2016 test of its predecessor. In every case the HP02 delivered disappointing performance relative to our pick. Given its high up-front cost and relatively weak performance, we can’t recommend it.

In addition to those models, we have reviewed more than 100 purifiers since 2013, testing many of them, including the following:

In our 2014 test, the Rabbit Air MinusA2 SPA-700A earned middle-of-the-road marks in performance, cost of ownership, and noise.

When we tested the Rowenta PU6020 on particulate filtration, it did not stand out. This model employs a unique formaldehyde-trapping filter, but we think people with chemical sensitivity should look to the Austin Air HealthMate HM400 for broader odor and molecular-pollution removal. This purifier is also pricey to buy and to run.

Although the Bissell air400 has specs comparable to those of the top-pick Coway, it costs over $100 more at this writing, and it has relatively few reviews on Amazon and on Bissell’s own site.

The Philips 1000 Series purifiers cost more and have similar or weaker specs compared with our Coway top pick.

The GermGuardian CDAP4500 is a small-space unit that usually costs $150—more than our pick in that category, the Blueair Blue Pure 411—mostly because it offers Wi-Fi connectivity, which isn’t useful or necessary.

The Rabbit Air BioGS 2.0 also fails the 4 ACH limit for a standard-size room and costs more than our Coway top pick.

The Alen BreatheSmart FIT50 and T500 are specced for standard and budget/small rooms, respectively—but they cost at least twice what our picks in those categories do.

The Honeywell HPA200 and HPA204 (black and white versions of the same machine) barely meet our 4 ACH minimum in a 350-square-foot room (with standard 8-foot ceilings), so you’d have to run them on high constantly to get the performance we expect.

The Honeywell HFD-120-Q has specs comparable to those of our budget pick but costs more.

Hamilton Beach offers no cubic-feet-per-minute or CADR numbers on its 04386A air purifier, so we dismissed it.

The Levoit LV-PUR131 has budget specs but costs twice as much as our budget pick.

The Oransi OV200 has budget specs, draws as much as 60 watts (our budget pick draws 3.6 on medium) and costs much more than our budget pick.

The QuietPure Home Air Purifier offers specs similar to those of our also-great pick for large rooms, the Blueair Blue Pure 211+, but it typically costs more.

A budget model, the popular Pure Enrichment PureZone 3-in-1 barely met our 4 ACH minimum for small spaces.

The GermGuardian AC4100 “desktop” air purifier doesn’t meet our 4 ACH minimum for small spaces.