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Whether you're plagued by allergies, smog, or smoke, a high-quality air purifier can go a long way in improving the air in your home or office. Our team of experts researched over 50 units before purchasing the best 15 available today to conduct our in-house, hands-on research. We assessed air cleaning performance, operating costs, ease of use, and the noise produced by the machines. Our in-depth research and testing will clear the air as to which air purifier is best suited to your home or office.
The Winix 5500-2 is one of the most effective air purifiers we tested, as it consistently reduced the measurable concentration of airborne particles by 99.99%. Perhaps equally impressive is that it achieved this without producing more than a gentle, inoffensive humming sound. Many of the other units produce an obnoxious and high-pitched whistle. This unit is loaded with features, including an air quality monitor, which automatically adjusts the settings based on current ambient air quality. The Winix also comes with a remote control and has different fan settings and programmable timers.
The obvious drawback is the price. This high-quality machine costs a great deal more than others in our fleet. Given its truly excellent performance, it is a worthy investment for your household's ongoing health. If you're looking for the absolute best-performing air purifier and willing to spare no expense, this may be the model for you.
Coming in at a close second in terms of performance is the Coway Airmega 1512HH. Over the course of an hour, it removed 99.84% of measurable airborne particulates from our testing room. While it's a few decimals shy of our highest-ranked model, this is still a top-notch performance. The fans on this machine are powerful enough to circulate cool air but not so loud as to disturb your evening Netflix binge. The built-in air quality monitor is convenient and accurate.
The upfront cost of this unit is higher than most of the other models we tested, but this cost comes with a caveat. Fortunately, the Coway is one of the most economical air purifiers to run. Its filters are long-lasting, and the unit uses very little electricity. This is a high-quality device that is a little bit more economical than our top choice.
Air Purifiers and COVID-19 (Coronavirus)
Credible research studies such as NASA's test results suggest that HEPA filter air purifiers can filter more than 99.9% of airborne virus particles that enter the air purifier. However, they cannot stop virus particles from contaminating surfaces or passing directly between people. Therefore, purifiers likely offer only marginal, if any, protective benefits from the virus itself and definitely should not be used as a replacement for any of the best practices put forth by the CDC or local healthcare and governmental organizations.
The Coway Airmega 400S is the go-to air purifier for those looking to clean lug-irritating particulates from the air in large spaces. The unit has one of the highest clean air delivery rates (CADR) in the class, it removed 99.96% of the particulates from our smoky room test in just 60 minutes (most of that work was done in the first 20 minutes), and it does all this work a relatively low noise level. Additionally, the unit has an air quality sensor that will control the operation to maintain high air quality while keeping power consumption to a minimum.
While the 400S is a large area air-cleaning workhorse, it isn't without its issues. Perhaps the biggest concern is its long-term costs. The air quality sensor goes a long way to keep power consumption — and thus utility costs — to a minimum. However, the unit uses the highest quality filters (true HEPA filters), and they are expensive. Depending on usage, one could see annual usage costs north of $250. That said, there are no other units that clean as much air as thoroughly and efficiently as the 400S. Plus, the purifier is supported by an app that allows one to monitor air quality and program its operation.
The Blueair Blue Pure 411's simple, stylish, and effective design is a great option for those looking to clean air in a smaller space such as a bedroom or office. The cylindrical design, cloth cover, and quiet motor make it a good pick for almost any space. In addition to being compact, the 411 is also lightweight at 5.3 pounds, making it easy to move around and even reasonable for travel. Finally, if you like simplicity in the operation of your devices, the single button with lights indicating the fan speed is about as simple as can be while maintaining multiple settings.
On the other hand, some may find the simplicity of the 411 to be a detriment. The lack of customization and automation certainly brought down its performance in our user interface assessment. This is because we prefer purifiers with air quality sensors that can tell the device to power down when the air has been thoroughly cleaned. A final concern is the cost of the replacement filters and the impact they will have on the long-term cost. We estimate that the purifier could cost as much as $67.40 per year if used daily. Despite these limitations and costs, we think that this device's size, upfront price, and effectiveness make it a great pick for those wishing to clean the air in small rooms.
The Levoit Core 300 is small but mighty. Considering its diminutive size, it offers truly excellent air-purifying capabilities. Weighing about seven and a half pounds, this machine is easy and convenient to move from room to room. Over the course of an hour, it removed 99.97% of measurable particulates from our testing room.
Because of its size and power, if you want to utilize it to its full potential, you are limited to using it in spaces 219 square feet or less. When set to high, this machine is quite noisy. Our testers didn't find the noise particularly obnoxious, but it is present. With a lower initial purchase price and low operating costs, this is an excellent unit for those on a budget.
A Note On Ionizers
Many purifiers utilize ionizers that release charged particles into the air that latch onto airborne particulates, making them easier to filter. However, some ionizers can create ozone as a byproduct, which can be a harmful lung irritant. While some ionizers are likely safe, we like to adhere to the precautionary principle in cases like these.
Why You Should Trust Us
Authors Buck Yedor, Nick Miley, and Genaveve Bradshaw have spent the last few years researching and testing a variety of health and wellness products, including air purifiers, humidifiers, electric toothbrushes, and fitness trackers. They've also tested many other home and kitchen products, from security cameras and wireless speakers to toaster ovens and pressure cookers. This team is no stranger to diving into the nitty-gritty details and conveying them to consumers clearly and comprehensively.
To test our lineup of the best purifiers, we used a professional grade air quality meter to measure airborne particulate concentrations and tested all of the purifiers in the same 150-square-foot room to keep conditions as consistent as possible. To choose the models that made it into this review, we researched over 100 different products before whittling them down to the 12 most promising purifiers. We then spent over 200 hours testing the air quality produced by each machine and assessing user-friendliness, noise levels, and overall operating costs.
To rate air purifiers, we divided our tests into four different weighted metrics. The results of our air cleaning performance tests factor most heavily into each model's final score. We also consider noise production, ease of use, and operating costs, as these factors significantly impact the user's experience. In the following sections, we delve into the details of these metrics so that you can pick the best air cleaning device for your needs.
In general, paying more for an air purifier will get you a greater clean air delivery rate, a quieter motor, and more customization features — there are exceptions though. The Winix 5500-2, for example, provides stellar performance and often sells for significantly less than its list price. The Levoit Core 300 also performs well above what its price suggests, offering high-quality air cleaning for less than many competitors. These two devices are great examples of value purchases that were revealed by our testing and detailed in the following review.
Air Cleaning Performance
Our most heavily weighted metric is air cleaning performance. This metric analyzes the purifiers' thoroughness in removing particulate matter, the rate at which the purifiers filter these particulates, and finally, their ability to remove odors while cleaning the air. To test this aspect of air purifiers, we sealed a 150-square-foot room in our testing facility and filled it with smoke by burning incense and paper. Once we got the room to the desired level of airborne particulate pollution, we ran each purifier for an hour, all the while monitoring the air cleaning progress with a Dylos air quality meter. Our tests focused on eliminating airborne particles measuring 2.5 microns and larger because this range includes most airborne allergens affecting humans, such as pet dander, pollen, and mold. We chose to focus on allergens because our research indicated that most people looking to purchase an air purifier are doing so for allergy relief.
Purifiers are rated with what is called a clean air delivery rate (CADR) which is essentially how much air they can process. This rating is related to the size of the area that they are going to operate in and, as a general rule, the CADR should be about ⅔ of the square footage of the area, assuming 8-foot ceilings. Understanding this rating will clarify the results of our tests because the majority of the models tested in our 150-square-foot smoke-filled room have CADRs that are more than adequate for such a space. Thus, almost every model in our test successfully removed 99% or more of the particulate matter in the allotted time. Those models that performed below this standard either lacked a CADR rating or their CADR was below 100.
Not surprisingly, the models with the higher CADRs did better than those with lower CADRs in our smoky room test. However, models such as the Winix 5500-2 and the Alen BreatheSmart 75i cleaned over 99% of the air in the first 30 minutes. These models have CADRs of 246 and 400, respectively. The Coway Airmega 400S and Blueair Blue Pure 311 Auto had 95% or more of the air cleaned in the first half of the test. The manufacturers of these last two models break up their CADRs into different types of particulate matter. As such, the 400S' CADRs are 328 for smoke, 328 for dust, and 400 for pollen, while the 311 Auto's CADRs are 250, 244, and 250, respectively.
As mentioned above, odor removal is a component of our air cleaning performance analysis. None of the purifiers performed particularly well in this regard. However, that was to be expected as the molecules producing many smells are small enough to pass through the air purifier filters. That said, the Coway Airmega 400S demonstrated the greatest capacity to remove the smell of smoke from the room following the smoky room test. A close companion in this regard is the Alen BreatheSmart 75i.
There are two main takeaways from the air cleaning performance metric. One is that it's vital to match the CADR to the room size — meaning that if you have a rather large room, you'll want an air purifier that can cover that amount of space. The other takeaway is that air purifiers are poor at removing odors. That said, the Coway Airmega 400S and Alen BreatheSmart 75i did pretty well in this difficult task. All told, these two purifiers are the best choices overall where air cleaning performance is concerned.
Since most people will be in the same room as the air purifier, any odd noises the device produces could have a significant negative impact on your relationship with the device in question. The good news is that none of the tested models are particularly loud — none registered more than 62 decibels on our sound meter, which is the equivalent of a normal conversational volume. Still, even relatively quiet noises can be annoying if they're at the wrong pitch. Thus, we spent a night with each in our bedrooms and hours working on our computers right next to each model as they ran.
The Winix 5500-2 is our top recommendation for those that are particularly sensitive to noise. We had to strain to hear it when it was set to its lowest mode. Even on the highest setting, it only gave off an innocuous, low-pitched hum.
The GermGuardian AC5350B is also relatively easy on the ears; it stays nearly silent in its low mode, only emitting a low hum when turned to high. The TruSens Z-2000 also maintains a low auditory profile. Its lowest setting is virtually silent, and even when cranked up to turbo mode, it produces only a fairly low-pitched, white noise hum.
The Coway Airmega 1512HH is almost silent in its lowest setting. Though it is just a bit higher-pitched than the field-leading Winix 5500-2, it generally remains in the innocuous, low-pitched genre when you crank it up to high. Also enjoying a top ranking in our noise assessment is the Levoit LV-H132. Like the other models, this unit is nearly silent when set on low and audible but not offensive when set on high. It should also be noted that this unit is smaller than the Coway Airmega 1512HH and the GermGuardian and thus has a less powerful fan. When considering the noise and power of a purifier, there is no other model that comes close to the Coway Airmega 400S. We were quite impressed at how quiet this machine is (just 52 disciples on high), as much smaller units produce significantly more noise.
In our noise testing, many models achieved just below the top tier. The Pure Enrichment PureZone 3-in-1's high setting produces a medium-pitched hum, which is a bit more noticeable than the top-performing models; however, its medium and low settings are virtually silent, thus matching the performance of models like the Coway Airmega 1512HH and Winix 5500-2.
Ease of Use
Outside of periodically replacing the filter, air purifiers are generally simple and require no maintenance. However, certain features can make day-to-day use a bit more enjoyable. Variable fan modes let you dial down the noise while watching TV, and remote controls let you do that without even leaving the couch. Handles and wheels make it easy to transport the purifier if you want to move it from the living room to the bedroom. If you're likely to forget to turn the purifier off when you leave the house, timers can help, too. We evaluated all of these aspects of user/device interaction to determine how easy they are to operate and incorporate into your daily routine.
Out of all the models we've tested, the TruSens Z-2000 delivers one of the most convenient user experiences. It has a sleek user interface, multiple fan speeds, and shutoff timers. Unlike other models, it has a unique air quality sensor pod that is separate from the purifier, allowing you to measure air quality anywhere in your home and relay that information back to the purifier. This means that you can program the purifier to react to air quality changes in your bedroom or your living room instead of the air quality directly adjacent to the purifier. Happily, we found installing and using this pod to be straightforward. Also, the Z-2000's relatively lightweight of 7.4 pounds, along with its carrying handles, made it easy to move from room to room despite its larger dimensions.
The Winix 5500-2 is a very close second to the TruSens Z-2000. Its control panel is straightforward, allowing you to easily access its shutoff timers, fan speeds, and auto setting, which adjusts the air output based on the ambient air quality, as measured by its internal air quality sensor. Thanks to a well-designed carrying handle, it is quite easy to move this unit around despite its 15.4 pounds.
The Coway Airmega 400S is also a top performer where ease of use features are concerned. This unit uses an app to control it remotely via a WiFi connection — a unique feature in the class. Its interface is also among the best, with a light bar displaying fan speeds controlled by touch. The unit has smart and night modes as well. The app has a timer, too, and accepts voice commands. While these are useful features, we acknowledge that some people may not want another app on their phone and, as some features (like the timer) are only available on the app, this can be seen as a mark against the 400S. The 400S is also quite heavy (24.7 lbs.) and, despite having caring handles, it is not what we consider a portable device.
Both the Levoit Core 300 and the Blueair Blue Pure 411 deserve special mention for their portability. Weighing only 7.5 and 5.3 pounds respectively and having compact, cylindrical dimensions, these units are the most convenient in the class to move, making them realistic to travel with if necessary. Both models are easy to set up and have simple but effective controls.
It's easy to forget that you're going to have to pay for replacement filters and electricity costs throughout the lifetime of your air purifier. To estimate how much each unit will cost buyers in the long run, we've measured every purifier's energy consumption and price-checked all of their replacement filters. Our lifetime cost calculations assume the national average of $0.13 per kilowatt-hour and average usage of 12 hours a day, as well as filters being replaced following the manufacturers' recommendations. We also include the cost of the device split up over five years into the calculation.
The Levoit LV-H132, PureZone 3-in-1, Coway Airmega 200M, and Blueair Pure 411 all performed at the top of the class in this assessment with annual costs of less than $75. The discerning reader may guess that these units have low clean air delivery rates (CADR) and thus low power consumption rates and smaller filters. For the most part, those readers are correct, as most purifiers in this group have CADRs of 120 or less. However, the Coway Airmega 200M is unique in that its average CADR is 240. Amazingly, the 200M also uses a HEPA filter — the highest standard non-industrial filter and often the most expensive. With the exception of a Blueair Pure 411, all the purifiers in this group use HEPA filters.
When we zoom in on filters with CADRs greater than 240, we see that, as expected, the cost of operation goes way up. Models in this group include the Blueair Pure 211, Coway AP-151HH, Honeywell True HEPA Allergen Remover, Winix 5500-2, Alen Breathesmart 75i, and the Coway Airmega 400S. The annual cost of operating these large-area air cleaning machines ranges from $112 to $268 annually, with the Coway AP-151HH on the low end and the Coway Airmega 400S on the high end. All of the units in this group employ HEPA filters.
All told, operating costs are largely based on the amount of air you want to clean — the larger the space you want to clean, the more you'll have to spend. To put it more plainly, the higher the CADR, the larger and more expensive the filter, the more electricity the unit will draw, and, in general, the higher the cost of the purifier itself. The takeaway here is that you want to make sure you are matching the room where the purifier will be used to the purifier's CADR.
Whether you live in the country, the city, or somewhere in between, air purifiers will improve the air in the room where they are operating. These machines are easy to use, fairly inexpensive to operate, and have real and immediate benefits to respiratory health and peace of mind. The above review looks at all aspects of these machines and rates their performance so that you can pick a device quickly and accurately. With the information provided above, you can breathe easy knowing that you have selected the right machine for your home or office needs and budget.
GearLab is founded on the principle of honest, objective, reviews. Our experts test thousands of products each year using thoughtful test plans that bring out key performance differences between competing products. And, to assure complete independence, we buy all the products we test ourselves. No cherry-picked units sent by manufacturers. No sponsored content. No ads. Just real, honest, side-by-side testing and comparison.