Air cleaners can capture wildfire smoke and COVID-19 virus particles. But which ones will help the most?
Each year, during the dry autumn spells and spring blooms, seasonal allergies strike. Air purifiers can help clear the air in your house — not to mention capture smoke particulates, mold spores, dust particles, pet dander, and COVID-19 virus particles. But with an overwhelming number of devices on the market, all touting various methods of air purification, how do you find the best air purifier?
I’ve extensively researched the field of products, tested the extra features on a dozen of the most popular models, interviewed various experts in the field of indoor air quality and written up the definitive list of the best air purifiers around. Ready to purchase an air purifier? Look no further.
Before the recommendations…
Before getting into the details of which devices are best and why, it’s important to understand the basic mechanisms that these products use to clean your air. To get a handle on these methods, I talked to Richard Shaughnessy, director of Indoor Air Research at the University of Tulsa.
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According to Shaughnessy, who has a doctorate in chemical engineering, most air cleaners run your air through a filter designed to catch airborne particles you might otherwise inhale. These are usually High Efficiency Particulate Absorbing filters and they’re designed to capture 99.97% of airborne particles sized 0.3 micron or larger. A HEPA filter reliably removes smoke (including cigarette smoke and smoke from wildfires), pollen, spores, dust mites and other particulate matter that pollutes home environments.
Activated carbon offers another type of filter, which captures odors and gaseous pollutants that can slip through a HEPA filter. “[A carbon filter is] good … to an extent,” said Shaughnessy, “but they need to have a sufficient amount of carbon. You don’t want breakthrough happening where the carbon becomes fully saturated and it releases what was captured back into the air.”
According to multiple researchers I talked to, most consumer air purifiers simply don’t have enough activated carbon to be an effective odor filter for more than a short period of time.
Another common type of air cleaning works via ionic filtering. These filters can be effective, according to Shaughnessy, but they have a number of shortcomings: Some don’t actually remove particulate from the home, but rather cause them to attach themselves to surfaces around the home. Others must be cleaned consistently, or they might begin to emit ozone — itself a pollutant.
While some ionic purifiers are effective and standards for them have risen significantly in recent years, the benefits an ionic purifier offers over a HEPA filter are in many cases negligible — particularly given the risk an ionizer occasionally poses.
An important standard to keep an eye out for is the AHAM Verified Clean Air Delivery Rate, which tells you how much air a purifier can process in a given time frame. Not every company uses this standard, but most do.
Recommendations get a little more complicated when companies don’t list a CADR, or when they employ proprietary filtration methods.
Dyson’s $550 air purifier doesn’t offer a CADR rating at all.
Some major players, like Dyson and Molekule, offer their own standards. That doesn’t necessarily mean that their devices are inferior, but rather that they require extra scrutiny. In these cases, I looked at the explanations presented by the companies themselves and talked to third-party specialists. By and large, such devices — even if they do accomplish what they claim — still end up overpriced compared with competing products with more readily accessible evidence backing up their claims.
It’s also important to note that many of the devices I tested have gone out of stock in recent months, given the rising demand for such devices during wildfire season and the ongoing pandemic. While that might mean some of the options below are out of stock, we’ve decided to keep our recommendations — and the rationales behind them — posted, so you can use them to find the best product for you. If and when we add devices to the list, we’ll update this story accordingly. For now, though, our recommendations are based on the included prices, and we would recommend avoiding sellers offering the same devices for significantly different price tags.
For the devices below, I primarily considered the power for the price (that is, the higher the CADR and the lower the price, the better). Secondarily, I looked at additional cleaning modes, the helpfulness of controls, the general design and the noise level. The perfect air cleaner looks sleek enough to fit into most modern decor, can operate as desired with minimal fiddling and can thoroughly and quietly clean your air.
After months of use in my own home, Coway’s HEPA air purifier has cemented itself as my favorite HEPA air cleaner around. Its current $180 price tag at Amazon isn’t bad for the 361 square foot coverage it offers, and its unique design and ion filtration technology set it apart from many other purifiers in the price range. The Coway’s striking, retro design was one of my favorites among the devices I tested.
Personally, while using the Coway, I’ve experienced fewer allergy symptoms during typically difficult seasons for me. A colleague’s mother also recently bought a Coway for smoke in her home during the west coast wildfires, and she noticed an immediate improvement in the air quality.
While the ionic filtration technology isn’t a huge plus, it also won’t produce significant ozone, as tested by the California EPA. If you want an air purifier for a midsize room, Coway’s HEPA air purifier is one of the best options around with one of the most adventurous looks.
The Blueair Blue Pure 411 is a simple, straightforward purifier with smart design and solid bang for your buck. You get particle and carbon filtration (the activated carbon filter removes odors, airborne allergens and gaseous airborne pollutants) that will work well in a 160-square-foot room, all for $120. Some devices, like Sharp’s Air Purifier, don’t even offer that much cleaning power at nearly twice the price.
The Blue Pure has different colored prefilter sleeves for the outside of the device, so it will fit into almost any color palette, and its single-button interface is as intuitive as it gets. The device is also light, with middle-of-the-road noise production. Besides the noise, the only real downside of the Blue Pure is the lack of extra goodies, like timer buttons.
I have mixed feelings about Dyson’s $550 TP04, but if price isn’t a concern and Dyson’s signature modern design appeals to you, it might be worth the splurge. The TP04 uses a HEPA filter, but provides no CADR. A Dyson spokesperson told me, “CADR as measured by some current methods is not an accurate representation of a real home,” and thus the company has developed its own testing procedures “to replicate a more realistic setting.” That includes a testing room that has over double the footprint of AHAM’s testing rooms, along with nine sensors placed around the space (versus AHAM’s single sensor). The Dyson TP04, perhaps unsurprisingly, performs well according to Dyson’s own metrics.
In addition, the TP04 features a handful of extra goodies, including an oscillating fan to help circulate clean air around larger rooms, an app with home air quality data and a small-but-nifty display. Our tower fan reviewer really liked these features for the TP04. But is all that worth the price bump from, say, Coway’s purifier?
For most people, the answer is likely no — especially considering that Dyson’s device hasn’t stacked up especially well against the competition in third-party testing, such as Wirecutter’s, where its performance was in line with the far more affordable Blueair 411. That said, if you love the aesthetic, the flashy extras and the built-in tower fan — and you don’t mind the asking price — Dyson’s TP04 might be a justifiable splurge.
The rest of the field
One of my original favorite air purifiers, Honeywell’s excellent Home 300 air cleaner, has sadly been removed from the list because it’s out of stock pretty much everywhere. If you find it in a store, though, I would highly recommend it for larger rooms: $250 for over 450 square feet of coverage is pretty fantastic. Alas, not all products live forever.
The remaining recommendations are only three of the 12 devices I tested. Other HEPA cleaners, like the $100 Levoit Core 300, the $160 Winix 5500-2, the $90 Bissell and the $85 GermGuardian all offer only so-so power for their prices. All four of those models offer carbon or charcoal filters for removing odors and gaseous pollutants, but the filters in all of them contain only a few ounces of the medium, meaning they won’t last long with use.
The IQAirHealthPro Plus wasn’t among the devices I tested, in part because I was looking at more affordable options. But IQAir’s $900 air cleaner is one of the few devices on the market to contain multiple kilograms of activated carbon, which will filter out odors and gaseous pollutants much more effectively than most consumer air cleaners under $1,000, according to specialists I talked to.
The Holmes air purifier is a cheap option for your desktop.
Two devices I tested featured an ionic filter: the $249 Coway AP-1512HH I mentioned above and the $230 Sharp FPK50UW. Sharp’s CADR rating is only 259 square feet, which is significantly lower than Coway’s and not great for the price.
The Partu ($50) and Holmes ($38) air purifiers were the most affordable devices I tested and they both offer true HEPA filtering for small rooms. I could see someone using them on a desk in an office, for instance, to great effect. But both felt a little cheap and neither gave an official CADR, so I would recommend saving up for something a little more reliable if cleaner air is a high priority.
What about Molekule?
You may have heard of another air purifier called Molekule, made by a company of the same name, which grabbed headlines for its attractive design and proprietary filtration technology back in 2017 — and is even, strangely enough, sold at the Museum of Modern Art in New York. What about that?
The Molekule presents a complicated problem: Its maker claims its proprietary PECO air filter destroys airborne particles much smaller than 0.03 micrometers, but it filters air at such a slow rate that, even if the company’s claims are accurate, it cleans the air very inefficiently compared with HEPA models (as Consumer Reports rightly pointed out in its highly critical review late last year).
Molekule was recently forced by the National Advertising Board of Review to retract misleading claims it made in its advertisements.
On the other hand, the Lawrence Berkeley National Laboratory, one of the premiere indoor air research centers in the country, recently released a government-funded study showing that the PECO effectively filters out volatile organic compounds — that is, compounds that can easily become gaseous pollutants in the air, which a HEPA filter does not capture. Reviewers at Consumer Reports and the New York Times’ Wirecutter, which called the Molekule’s larger model “the worst air purifier we’ve ever tested” and the Air Mini “the second-worst,” didn’t appear to test VOC reduction.
We can’t recommend the Molekule Air Mini Plus, which I tested, as a result of these problems coupled with a recent decision by the National Advertising Review Board to force a retraction of many of Molekule’s misleading advertising claims. That said, the air purifier does appear to address a problem that most HEPA filtration cleaners simply don’t: the presence of gaseous pollutants in the home. Such pollutants have plenty of sources, whether from paint, furniture, cleaning solutions or even some composite boards. For that reason alone, Molekule’s eye-catching brand is worth keeping tabs on — especially as its latest air cleaner was just approved by the FDA as a Class II medical device.
Do you even need an air purifier?
Given the rise of COVID-19 over the past few months, you may be thinking about air purifiers in a fresh light. In home settings though, transmission usually occurs through close contact, which means an air purifier probably won’t protect you if a roommate or family member in the same house gets sick. Purifiers may help businesses and restaurants trying to improve the air in their indoor spaces.
Beyond COVID concerns, in home settings, air purifiers don’t offer much value to the average consumer. According to microbiologist and Vice President of Scientific Communications at the American Council on Science and Health Alex Berezow, “Unless you have some sort of medical condition (asthma, allergies), I just don’t think an air purifier is worth the money.”
Human lungs, Berezow pointed out in a recent blog post, filter the air we breathe sufficiently — especially in places like most parts of the United States, where air is fairly consistently clean.
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On the other hand, for households with an asthmatic or otherwise immunocompromised child, air purifiers have significant benefits, according to Berezow and Dr. Elizabeth Matsui, a professor of population health and pediatrics at the University of Texas, Austin’s Dell Medical School.
Matsui has extensively researched the effects of air purifiers on children with asthma and says the devices can make a big difference — though they’re no substitute for well-ventilated and smoke-free homes or proper medical care. Furthermore, there is no evidence to suggest that air purifiers diminish the chance of children developing asthma.
In short, air purifiers are popular for a reason: They mostly do what they say, cleaning the air inside your home. And depending on your health needs, or if you live in a home with many sources of air pollution, cleaner air might really make a big difference for you or your children. If you think the benefits of an air purifier might help someone in your own home, it’s always worth talking to an allergist. If you’d rather just grab an air cleaner and call it a day, you can’t go wrong with the recommendations above.