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 Feb. 11, 2024 8:53 a.m. PT Air Filter 20x20x1
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Decide which room or rooms you'll be using your air purifier in to ensure it has enough power.
Both the cost of the machine itself and replacement filters should be considered.
While HEPA filters remain the best option for most, there are also activated carbon, negative ion and ultraviolet filters to consider.
Allergies can be a daily struggle for people who live in dusty climates or are sensitive to dander and other allergens. A great way to combat this long-term is by getting an air purifier in your home. These are used to filter out viruses, dust and other air pollutants and circulate clean air throughout your home. Our top pick by far is the BlueAir Blue Pure 311i Max . It's a quiet option at a reasonable price with great performance in medium-sized spaces. However, this isn't the only quality option, there are others worth a look.
CNET's favorite air purifier is the Honeywell Home Allergen Plus.
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 live in an area where wildfires can happen and want to prepare for the spread of the 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 pre-smoke-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 under $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.
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.
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.
Some air purifiers, including the Coway Airmega 400, are designed to purify rooms as large as 1,500 square feet.
When considering your budget for an air purifier, you might also want to consider the cost of replacing the filter roughly every six months.
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 gasses or volatile organic compounds out of the air. Gasses in your home air typically present themselves as odors from pets, cigarettes or cooking.
A HEPA filter can effectively remove smoke particulates from the air.
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.
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. Since the start 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.
Air quality is a real concern for many Southern California residents with smoke from wildfires and smog having been linked to numerous respiratory diseases.
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.
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.
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:
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
Blueair 211 Replacement Filter 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.