CNET experts have tested the top air purifier models that will protect your lungs from allergens, pollen, wildfire smoke, pet hair, dander, dust and other toxins.
Updated Nov. 13, 2023 4:00 a.m. PT
Our expert, award-winning staff selects the products we cover and rigorously researches and tests our top picks. If you buy through our links, we may get a commission.
Reviews ethics statement
Laboratory Technical Project Manager Gianmarco Chumbe has been part of the CNET Home team since 2018. He is in charge of developing and carrying out testing procedures for a wide variety of home appliances and smart devices including robot vacuums, smoke/CO detectors and air conditioning units.
He takes a data-driven and creative approach to every project he is involved in, honoring his background in Science and Engineering.
ExpertiseSOP development and laboratory testing of home appliances and smart devices
Pamela is a freelance food and travel writer based in Astoria, Queens. While she writes about most things edible and potable (and accessories dedicated to those topics,) her real areas of expertise are cheese, chocolate, cooking and wine. She's a culinary school grad, certified sommelier, former bartender and fine dining captain with 10 years in the industry. When not sitting at the keys, she leads in-home cheese classes, wine tastings and cocktail demonstrations.
If you live in an area prone to dust or you're allergic to the materials in the air around you, it might be a good idea to invest in an air purifier. The best air purifiers use a variety of technologies to filter particulate matter out of the air, including dust, dander, allergens, viruses and other pollutants. They also recirculate cleaner air back into your living space. Overall, the most impressive air purifier we've tested is the BlueAir Blue Pure 311i Max, as it offers category-leading performance for medium-size spaces in an efficient, whisper-quiet design at a reasonable price. Still, there are a number of other brands and models worth considering as you shop.
Air purifiers employing HEPA filters -- defined by the US Department of Energy as high-efficiency particulate air filters that are capable of removing at least 99.97% of airborne particles with a size of 0.3 microns -- are the most numerous and most highly rated type available. Most air purifiers are equipped to handle one or two rooms, with a few models that claim to purify the air in an entire home. Whether you suffer from seasonal allergies or want to prepare for wildfires spreading their ashes across the US, you might consider protecting yourself against airborne toxins at home with an air purifier.
Air purifiers can help make life easier for those with allergies or other respiratory conditions, especially if you put your air purifier in the right place. Even if you don't have any issues breathing easy, having an air purifier for your home can offer peace of mind that you're breathing the cleanest air possible within your specific living conditions. Our CNET experts have spent years testing air purifiers and diligently tested each of the models below over the course of several weeks, evaluating their performance, features, ease of use and noise level at various settings while looking out for any glaring operational problems. Keep reading for the details on our top-tested picks, straight from the CNET Labs product testing facility.
Every air purifier we test goes straight into our custom-built test chamber, where we release a controlled amount of smoke into the air and see how long it takes for the purifier to get things back to normal. Among all of the medium-size air purifiers we tested, BlueAir’s Blue Pure 311i Max was the top finisher at both low and high fan settings, bringing the particle count down to presmoke bomb levels in 6.6 and 2 minutes, respectively. That’s quite an impressive result. On top of that, the 311i Max was the second most energy-efficient unit in its class and pleasingly quiet too, reaching only 46.1 decibels when running at its highest fan setting.
The Blue Pure 311i Max is an innovative air purifier that features voice controls and comes equipped with a five-color air quality indicator and a pollution-detecting particle sensor. Download the BlueAir App and you’ll be able to track air quality in your home in real time, control the air purifier remotely and even track filter usage so that you can order a new one when the time comes.
The Blue Pure 311i Max retails for $230, though as of writing this you can catch it at a discount from both Amazon and Best Buy. BlueAir claims it can cover an area of up to 900 square feet and has a CADR rating of 250 cfm for smoke, pollen and dust. It’s a simple, well-designed air purifier that performs exceptionally well, both in terms of energy usage and particle removal. If you’re looking to improve the air quality in your home office or home gym, this is definitely your guy.
Good air quality is particularly hard to maintain in large and open spaces. For this category, the most consistent unit was the Kenmore Smart 2000e. At low, it was able to purify the air in our test chamber in approximately 6.25 minutes, the fastest of the bunch. At high, it came in second, reaching the finish line in only 2.5 minutes.
On top of that, the Kenmore Smart 2300e was one of the most efficient large-size air purifiers we tested and would add less to your monthly energy bill than similar-size units like the Coway Airmega 400s or the EnviroKlenz Air System Plus. It wasn’t unreasonably loud, either, keeping the fan noise below 40 decibels at low and medium settings and topping out at 50.6 decibels at its highest setting. That’s comparable to the noise generated by rainfall.
The Kenmore Smart 2300e retails for $300 and claims to effortlessly cover up to 2,300 square feet of space. Other great features include a digital display that shows a color-coded, real-time air quality score, three-stage filtration (including an activated carbon filter), app-control that allows you to monitor your home’s air quality, control the unit from your phone and order replacement filters when a change is due. If you have a particularly large living room or are looking to improve the air quality in your entire apartment, this air purifier is what you’re looking for.
Best air purifier for bedrooms and other small spaces
BlueAir Pure 511
Not enough good things can be said about this air purifier, which notches another win for BlueAir -- this time in the small-size category. In our particle removal test, the Pure 511 cleared our smoke-contaminated test chamber air back to non-hazardous conditions in less than 20 minutes at its lowest fan setting. Every other small-size air purifier we tested took at least 35 minutes to clean the air in that same test. The Pure 511 led the way on the high setting too, clearing the room in a category-leading 7.5 minutes.
On top of that, the BlueAir Pure 511 was the second quietest small-size unit we tested, reaching only 44.3 decibels at its highest fan setting. That’s library-quiet, literally. It’s also an extremely efficient air purifier, achieving best-in-class performance with the second lowest power draw of any unit we tested. In fact, if you ran the BlueAir Pure 511 on its highest setting 24/7 for 30 days in California, where energy rates are well above the national average, it would add less than $3 to your energy bill, in total.
The Blue Pure 511 has a CADR of 112 cfm for smoke, pollen and dust, claims to cover up to 432 square feet of space and retails for only $100 at the time of this publication. It features a HEPA Silent air filter and single-button operation. It’s light-weight, portable and efficient. If you plan on having an air purifier in your bedroom running nonstop, this is definitely the best choice we’ve found -- and at $100, it's a great small-size budget pick too.
Show expert takeShow less
Factors to consider when choosing an air purifier
Coverage and size
The primary consideration in buying an air purifier for home use is how much square footage you're trying to cover. Trying to save money by getting a smaller air purifier than what you actually need will just give you disappointing results. The air purifiers on this list all have high proficiency, so any one of them will effectively clean the air in your home, provided they're the correct size and placed appropriately, and with the filters and prefilters maintained accordingly. After room capacity, the amount of space the device itself takes up may be important based on the geography of your room and where you're hoping to put it.
When considering your budget for an air purifier, you might also want to consider the cost of replacing the filter roughly every six months.
Types of air purifier
While this list consists only of HEPA air purifiers, which are the most available and highest functioning models on the market, several of them use more than one type of filtration technology. In order to better understand those aspects of your air purifier, or if you want to consider buying another type of air purifier, here's a breakdown of all of the different methods of air purification technology:
HEPA air purifiers: Standing for "high efficiency particulate air," air purifiers with HEPA technology use a fiberglass filter that traps particles of a certain size out of the air.
Activated carbon air purifiers: Where HEPA filters manage solid particles in the air, most of the air purifiers on this list also include activated carbon technology (which is the same thing as activated charcoal), whose porous nature helps filter gases or volatile organic compounds out of the air. Gases in your home air typically present themselves as odors from pets, cigarettes or cooking.
Negative ion air purifiers: Ionic or negative ion air purifiers work by using high voltage to give an electrical charge to particles or molecules in the air, which causes them to clump together, and then seek out positively charged molecules with which to bond. Certain models that use this type of technology also include a positively charged collector plate that the ionized particles will stick to, taking them out of the air. (Without a collector plate, these particles are no longer circulating in the air, but may hang on surfaces in order to be cleaned or vacuumed out of your home.) Most models employing this technology don't use fans, which requires more time to filter the air in a room but also make for extremely quiet conditions. Molekule and Dyson make popular models that use variants of this type of technology.
UVGI air purifiers: "Ultraviolet germicidal irradiation" air purifiers are similar in mechanical function to HEPA air purifiers, in that they use fans to recirculate the air in order to purify it quickly. Inside the device, UVGI air purifiers rely on shielded ultraviolet light to neutralize dust and allergens. This type of technology isn't available in air purifiers for home use, however, and is typically employed in larger systems available for public settings such as office buildings.
Location and living conditions
For some people, having an air purifier in the house may be more of a necessity than a luxury. If you live in an area where allergy season tends to wreak havoc or where wildfires and smoky skies are common, an air purifier can seriously help improve the breathability of the air in your house. In light of the COVID-19 pandemic, plus an increase in wildfire activity, we are all becoming more aware of air quality. (Arguably severe allergy sufferers have always been aware of air quality.) While having an air purifier isn't a failsafe against COVID-19 -- you're more likely to get the virus from repeated close contact with someone in your home than from particles lingering in the air long enough to get filtered out -- they can be especially effective for those with asthma or allergies.
Depending on your living conditions, if there are numerous pollutants affecting the air in your home, the cleaner air and increased airflow that air purifiers provide can make a big difference for the quality of life (and air) of those in your household. If you're thinking of getting an air purifier and want additional reassurance, it may be worth speaking to your doctor or allergist.
There's a good amount of research and expert guidance that goes into choosing the best air purifier for you and your family. First consider how much you can comfortably invest in air purification. Will you need an ionic air purifier or a full home filtration system? Do you want a purifier with an activated carbon filter? We're here to answer those questions and help you sort through your options.
How we test air purifiers
In order to help inform our air purifier picks, we gathered 14 of the most popular models out there at the CNET Labs product testing facility in Louisville, Kentucky, where we put them through the same rigorous set of tests. Working with trusty lab associate Eric Snyder, our goal was to determine which air purifiers offered the best performance in terms of particle removal efficiency, energy consumption and quietness, while also evaluating their respective feature sets and value. Tag along as we unveil the science behind our thought process.
The particle-removal test
As you may already know, the air we breathe isn't just air. If you were to walk outside in the middle of the night and turn on a flashlight, you'd bear witness to a universe of tiny fragments floating around and being carried by the wind. But what is that stuff, anyway?
In truth, it's a combination of anthropogenic (human-generated) and naturally occurring particles. The former is composed mostly of urban, industrial and automotive emissions of hydrocarbons, nitrogen oxides and combustion byproducts, and the latter is mostly represented by smoke from forest fires, sulfates, soot and matter from volcanic activity around the globe. We are, at all times, breathing in a mixture of it all.
According to the US Environmental Protection Agency, some of these microscopic solids and liquid droplets, which can be made up of hundreds of different chemicals, are so tiny that it's almost inevitable to inhale them. PM10 and PM2.5, which are particles of less than 10 and 2.5 micrometers in diameter, respectively, pose the greatest risk to human health since once inhaled, they allocate deep into the lungs and even into the bloodstream, impairing the proper functionality of the lungs and heart.
Air purifiers are supposed to help us improve indoor air quality conditions by removing these types of particles from the air -- but how well do they do that? That's where our CNET Labs team comes in. Put simply, our mission was to create an environment in which we exposed each air purifier unit to particle-saturated air of roughly the same concentration in order to assess how quickly and efficiently they get the air back to breathable conditions.
To achieve this, we needed to find a way to produce a quantifiable and fairly repeatable amount of particles; an environment or "test chamber" in which these particles and the air purifier units would be contained; and an accurate particle counter that acts as our control device and allows us to visualize this data. Here's what we came up with:
Custom made smoke bombs, which are made of 50% potassium nitrate (KNO3), 40% sucrose (sugar) and 10% sodium bicarbonate (baking soda), and a safety fuse for safe ignition at a distance. The sugar acts as our fuel source, while the potassium nitrate acts as an oxidizing agent and the baking soda ensures that our dry mixture sustains a slow and even burn.
Our air purifier test chamber, designed and built by Eric and myself. Its features include a clear-view front panel made of plexiglass, a gloved hand access on the right, which allows us to manipulate the air purifiers, a particle counter holder for our control device, two fans that ensure proper mixing of the air and smoke inside the chamber, vent ports that ensure there is a small amount of fresh air at all times, an ignition port to light up the smoke bombs from outside the rig, and an exhaust port that removes the remaining smoke safely from the chamber and the building after each test. The chamber is not hermetically sealed, but it's tight enough to ensure that no hazardous amount of smoke escapes to the surroundings.
Using the Temtop PMD331 Particle Counter, we were able to verify that only 5 grams of our smoke bomb dry mixture produces roughly between 590 million and 610 million particles per meter cubed. The device is able to count particles of different sizes, including PM2.5 and PM10, and it logs this data once every 15 seconds. Even though we're able to count particles of different sizes individually, it's the total number of particles we care about. That is, the sum of all particles of different sizes.
Having figured out the essentials, our testing procedure is carried out as follows: we turn on the particle counter and let it run continuously. We prepare a 5-gram smoke bomb, which is ignited via the ignition port after installing the air purifier and ensuring proper sealing. Once the air in the chamber becomes particle-saturated (greater than 580 million particles/m3) we turn on the air purifier in question. The data extracted from the Temtop allows us to accurately track the impact that the air purifier has on the particle count in real-time.
Under normal conditions -- that is, when there was no smoke in the test chamber -- the total particle count reported by the Temtop was around the 10 million mark, so think about this as the "finish line" for this particle removal race. In our test logic, the faster the air purifier gets the particle count back below 10 million particles per meter cubed, the better. We carry out this test twice for each air purifier, one at the lowest fan setting and another at the highest fan setting to visualize the range of operation of each unit. Check out the results for each unit we tested at both low and high fan settings in the GIFs below:
The noise level test
This is a simple test, but one that's telling. Using a decibel meter, we measure how loud the air purifiers are at their low, medium and high fan settings. This is particularly important if you plan on having your air purifier in your bedroom and leaving it running through the night without disrupting your sleep.
We perform this test in our sound-enhancing studio to make sure that the decibel meter picks up only soundwave stimuli from the air purifiers, excluding other possible sources. The lower this number, the quieter the air purifier runs. You can see the results for yourself in the graph below -- each unit we tested clocked in at around 35 decibels at its low setting, but we saw greater differentiation at medium and high settings.
If you're like me and your allergies are your worst enemy, you'd prefer it if your air purifier is running all the time. The only concern is that your energy bill will definitely increase. But by how much?
To answer this question, we use a device called Kill-a-Watt and measure how much power each air purifier consumes at different fan settings. From there, we can correlate this to an average monthly cost of running the unit nonstop. All you need to know is the energy cost per Kilowatt-hour in your state. The following formula describes it best:
average cost to run an air purifier nonstop for a month = watts consumed/1000 * 24 hours * 30 days * average utility cost per KWh in your state
The chart below shows how much each air purifier we tested would cost to run for an entire month at its high fan setting in a variety of states with different energy rates.
Other air purifiers we've tested
Levoit Core Mini: The tiniest and most affordable of the bunch, which is great considering it has a 3-stage filtration system and you can even add essential oils for aromatherapy. Bottom of the table performance, unfortunately.
Medify MA-25: The performance didn't justify the price with this unit. It struggled in our particle removal test, and was the loudest of the small-sized air purifiers we tested.
Kenmore 850e: This unit offers decent particle removal efficiency thanks to its three-stage filtration system, and sports a touchscreen display and dimmable night light. It wasn't quite as strong a performer as our top pick for small spaces, the BlueAir Pure 511, but at a retail price of $100, it's a budget-friendly alternate.
GermGuardian AC4300: Comes equipped with a HEPA filter with added antimicrobial agent, an activated charcoal filter and UV-C light as germicide, and a filter change indicator. It was just a middle-of-the-pack performer, though.
Levoit Core 400s: Our runner up for medium-sized spaces. It's the most expensive medium-sized air purifier we tested but it offers great performance in all test categories. Features include Wi-Fi connectivity, voice control and the VeSync app, which allows you to monitor air quality and control the unit remotely. It's also compatible with Google Assistant and Alexa.
Veva 8000: Not a lot to highlight about this unit other than the low cost and the super quiet design. It was a bottom-of-the-pack performer in our particle removal test, and in terms of energy efficiency, as well.
TruSens Z-2000: Aso in the lower bracket in terms of particle removal efficiency. It does come with an air quality sensor and UV-C light, both of which make it a decent option for the price.
Coway Airmega AP-1512: Above average performance overall. Sports a color-coded air quality indicator, eco-mode, filter alerts and has an ionizer option that enhances bacteria and virus removal.
CleanForce CP-Rainbow: I was impressed by the performance of this unit. It was the fastest air purifier at removing particles at high fan setting, removing all smoke particles in just 1 minute and 45 seconds, which is just incredible. It comes with app control and voice command, an HD LED display for air quality monitoring and color-coded indicators. It offers just a hair fewer features than our winner for best air purifiers for large spaces, but it's considerably more expensive, which is why it's not topping the list.
Coway Airmega 400S: Acceptable performance, very sophisticated filtration system, voice and app control, air quality monitoring via the app and color coded LED indicators on the unit. There are just better options for the price.
EnviroKlenz Mobile UV: The highlight of this unit is that it comes with two UV-C bulbs to eliminate airborne bacteria and viruses. Other than that, it's quite large and heavy, sitting at 40 pounds. It took the longest to purify air in our particle removal test, and it's quite expensive both to buy and operate.
You may have heard of another air purifier called Molekule, which grabbedheadlines for its attractive design and proprietary filtration technology back in 2017. But the Molekule presents a complicated problem: Its maker claims its proprietary PECO air filter destroys airborne particles much smaller than 0.03 micrometer, but it filters air at such a slow rate that, even if the company's claims are accurate, it cleans the air inefficiently compared with HEPA air purification models (as Consumer Reports rightly pointed out in its highly critical review).
We have tested but don't currently recommend the $500 Molekule Air Mini Plus as a result of these problems, as well as a 2020 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 since the company merged with AeroClean, a pathogen elimination technology company, in October 2022.
Dyson's devices offer a similar but slightly different problem. Some of its air purifiers, such as the Dyson Pure Cool TP04, which we also tested in previous years, use a HEPA filter, but provides no CADR. A Dyson spokesperson told us, "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 Dyson TP04 air purifier includes 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. But is all that worth the considerable price bump? We'll have a much better sense once we've had a chance to test it out in our new test chamber, but until then, we suspect there are better values to be had.
Air purifier FAQs
How do air purifiers and HEPA filters work?
HEPA stands for "high efficiency particulate air" and is a type of filter standardized by the US Department of Energy for filtering particulate matter of a specific size out of the air by using a maze of interwoven glass fibers to trap those particles. HEPA air purifier models use fans to suck air into the device in order to trap microscopic particles in the air, which can include dust, bacteria, viruses, pollen, smoke and mold, and recirculates the clean air back into the room via a vent. HEPA standards are different in the US and Europe, with the US standard requiring HEPA filters to filter 99.97% of particles 0.3 microns in size out of the air. Coway includes an excellent breakdown of this type of filtration on its website.
Do air purifiers increase or decrease oxygen in the room?
Air purifiers don't affect the level of oxygen in the room in any way. Your air purifier is recirculating the air already in the room and cleaning it by passing it through a filter where microscopic, solid particles are removed. It is neither removing nor adding additional oxygen into the space. Air purifiers are also not the same as freestanding air conditioners, though the increased airflow from an air purifier may make the air in your home appreciably cooler.
Where is the best place to put an air purifier?
Firstly, you want to make sure to put your air purifier in a room that is equipped to handle, size-wise. As for placement within the room, a central location will make for the most efficient air purification. In order to avoid tripping over it, however, it's fine to put your air purifier in a more discreet location, just be sure to understand where its input and output vents are located and make sure those pathways aren't blocked. Near doorways and vents that are also creating airflow may help with your air purifier's efficiency.
How often should I change the filter on an air purifier?
How often you need to change the filter on your air purifier depends on several factors, not the least of which is how polluted your air is to begin with, and how often and at what speed you are running your air purifier. Most air purifiers have a multistep filtration system, including a prefilter in addition to the HEPA filter, which in some cases may be washable, and is used to capture large particles such as pet hair. Taking good care of the prefilter will help extend the life of the HEPA filter. Most of the brands on this list recommend changing the filter every six months. A few suggest every year, largely depending on the size of the HEPA filter and the prefiltration system. New filters and prefilters are often available from the same retailers that sell the air purifiers, or you can buy them through the brands' websites, some of which offer subscription programs for replacement filters at a discount.
Do air purifiers prevent the spread of diseases such as COVID-19?
The short answer is yes. HEPA air purifiers capture virus particles, removing them from the air. But don't count on air purifiers to protect you from virus particles if you're cohabitating with a contagious person. When CNET spoke with Richard Shaughnessy, director of indoor air research at the University of Tulsa, in 2022, he said transmission of COVID usually happens due to close contact with an infected person. If you're sitting on a couch and chatting with someone who is infected, an air purifier across the room isn't going to remove all the harmful particles exhaled before they have a chance to reach you.