Best air purifier for 300 sq ft room

If you’re suffering from allergies this season, one of the best air purifiers can help. Air purifiers work by sucking in the air and then filtering out any pollutants, before pumping it back out into the room. In doing this, these devices effectively remove all sorts of airborne particles, from dust and pollen to pet dander — plus, they can be useful for deodorizing a room and can even catch viruses as well. Since so many of us have started to work from home more regularly, these appliances have soared in popularity. After all — they make the environment a more pleasant one to breathe, and can help those who suffer from allergies as well as asthma.   

Air purifiers come in all shapes and sizes and there’s a vast range of prices to reflect premium brands and added features. But, how can you tell which will actually make a difference to your air? To help you out, we’ve tested a selection of the most popular air purifiers to see which actually deliver in both performance and design. We considered everything from noise to energy consumption, and even sent them out to a lab to assess the efficiency of the air filtration. We’ve got a recommendation to suit every situation, whether you’re shopping on a budget or want all of the bells and whistles. These are the best air purifiers. 

The best air purifier you can buy today

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Best air purifier overall

Specifications

Dimensions: 20 x 13 x 13 inches

Weight: 12.5 pounds

Suggested room size: 550 square feet

Filters: Particle/carbon/HEPASilent

CADR (smoke/dust/pollen): 353/347/380

Speeds: Three speeds and an auto mode

Noise level (dB): 35.6/60.8

Energy use (24 hours): 0.159 kWh

Warranty: One year

Reasons to buy

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Cleans air efficiently

Reasons to avoid

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Larger footprint

Throughout our testing, one cube-shaped air purifier stood out above the rest. The Blueair Blue Pure 211+ Auto dominated the competition. It has the ability to clean the air in a large-sized room while using minimal power and creating very little noise. It might not be as flashy as its more expensive cousin, the Health Protect 7470i, but it doesn’t need the extra expense to get the job done.

Designed for large spaces (rooms up to 550 square feet), its average Clean Air Delivery Rate (CADR) of 360 for smoke, dust and pollen was the highest of all those we tested. That means it’s both fast and efficient at removing pollutants from the air — one of the 5 reasons you need an air purifier.  

It’s also one of the best looking air purifiers with a unique top grate and sleek pre-filter skirt that takes away a lot of the technological intrusion that other devices have. The white shell also helps it disappear into your decor.

Devilishly simple to set up and use, it features only one button to cycle through all four of its modes. The auto mode is truly supreme — able to pick up speed and power within seconds of detecting something in the air. One of its only demerits is its night mode, which slows the fan down so much that it doesn’t work nearly as well as its lowest daytime setting. That said, we feel there really isn’t a better air purifier out there. 

Read our full Blueair Blue Pure 211+ Auto review. 

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Best value for a large room

Specifications

Dimensions: 22.3 x 20.0 x 10.8 inches

Weight: 17 pounds

Suggested room size: 465 square feet

Filters: HEPA filter and activated carbon pre-filter

CADR (smoke/dust/pollen): 300/320/300

Speeds: Four speeds

Noise level (dB): 41/59.6

Energy use (24 hours): 1.002 kWh

Warranty: One year

Reasons to buy

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Strong performance

Reasons to avoid

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Noisy

The Honeywell HPA300 is a bulky beast of a device that offers good value for money considering its impressive performance. It’s a large oval air purifier with slats all around, making it look like it belongs in the office of a dystopian future. It’s also pretty heavy at 17 pounds, so this is the kind of air purifier you won’t want to move around once you set it down. 

A truly powerful device, the HPA300 scored second to the Blueair Blue Pure 211+ auto on the CADR test, with its three filters able to remove most of the pollutants in a large-sized room of 465 square feet. With an average CADR score of 306, it did perform slightly better on dust versus pollen and smoke. 

We found it pretty simple to set up — all you need to do is open the front panel and take the plastic off the included filters. Nicely hidden near the top control panel is also a quick reference guide, so you don’t have to go searching for the manual that inevitably goes missing after just a few days. It’s not got a wide range of settings and features, but it does offer a timer as well as a dimmer for nighttime use. However, there's no auto mode, which is a shame. 

The replacement filters are very reasonably priced and only need to be swapped out every 12 months. It’s noisier and has a higher energy output compared to others on the list, but the purifying capabilities make this easy to overlook — that’s why we feel it’s one of the best air purifiers. 

Read our full Honeywell HPA300 review. 

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Best smart air purifier

Specifications

Dimensions: 27.2 x 11.8 x 11.8 inches

Weight: 27.6 pounds

Suggested room size: 418 square feet

Filters: HEPASilent Ultra

CADR (smoke/dust/pollen): 270/275/280

Speeds: Three speeds and an auto mode

Noise level (dB): 35.3/48

Energy use (24 hours): 0.241 kWh

Warranty: One year

Reasons to buy

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Great performance

Reasons to avoid

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Can be difficult to move around

The most expensive and heaviest air purifier we tested is also one of the best air purifiers. It can clear a room of pollutants efficiently, increasing its strength with relative ease whenever  needed. With two lights on the front — one representing gas pollutants and the other for larger particles — the Blueair Health Protect 7470i has the clearest indicator of air quality we’ve seen out of any of the devices. Whenever we started cooking, those lights would turn bright red and the fan would kick into overdrive. 

Blueair’s top-shelf machine has all the technological bells and whistles anyone would ever want. It’s got an LCD screen on top of the device that gives you up-to-date information on what it’s sensing, including the local temperature, filter lifetime remaining, and the relative humidity of the room. Having that information is nice, but it doesn’t really add anything to the experience unless you really love data. This is the only air purifier we tested that’s accompanied by an app (Android and iOS). It’s very simple to use and every feature is conveniently located on one page. One feature solely possible through its app is the capability to dim all the lights while keeping the fan at a particular setting — it gives a truly customizable experience and is a great alternative to night mode.

The weight of this air purifier does make it a bit cumbersome when trying to move it into different rooms, but it is the only device we tested to include a pair of wheels to help with this. Even though it is the quietest of the bunch, it’s also worth mentioning that it tends to use more energy than other devices at 0.241 kWh in 24 hours, so all that data comes at a cost. 

The recommended room size for this model is a bit smaller than its sibling, the 211+ Auto, but it still works well in quite a large living space at about 418 square feet. It had an average CADR score of 275, performing best on pollen versus dust and smoke. 

If you want a quality air purifier and don’t mind the hefty price tag, then we highly recommend the Blueair Health Protect 7470i. It’s an ideal purchase if you want to see the impact your air purifier is having in real time. 

Read our full Blueair HealthProtect 7470i review. 

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Most energy-efficient air purifier

Specifications

Dimensions: 16.8 x 18.3 x 9.6 inches

Weight: 12.3 pounds

Suggested room size: 361 square feet

Filters: Pre-filter, Carbon filter, True HEPA

CADR (smoke/dust/pollen): 247.5/232.3/241.3

Speeds: Three speeds, plus an auto and eco mode

Noise level (dB): 36.8/58.3

Energy use (24 hours): 0.082 kWh

Warranty: Three years

Reasons to buy

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Small footprint

Reasons to avoid

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Loud

There’s no denying how much the Coway looks like an iPod Shuffle, but if you don’t mind that outdated Apple aesthetic, it’s a great air purifier. 

It’s got a built-in auto sensor, which is a must-have feature for top-of-the-line air purifiers. Without it, you’re stuck with your purifier running on the highest speed for the best purification, while building up quite the utility bill. It was also the only purifier we tested that included an eco setting. What this means is that if there is no change in air quality for a specified amount of time, the machine will go into standby mode, saving you countless kilowatts and money on your energy bill.

It received an average CADR of 240, with a similar performance across dust, smoke and pollen, and would suit a room size of 384 square feet. That’s quite a strong performance considering its compact design. 

However, one downside to this purifier is the price of replacing its filter. You’re paying a little less than a quarter of the original price, $57.49, to replace the filter every six months to one year, which isn’t ideal.

Saying that, the device itself comes at a great price and has enough layers of filtration to earn a spot on our list of the best air purifiers. Just keep in mind that the sleek plastic exterior will pick up your fingerprints quite easily, so it may need a cleaning every once in a while. 

Read our full Coway Airmega AP-1512HH review. 

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Best air purifier for technology buffs

Specifications

Dimensions: 23.6 x 15 x 8.2 inches

Weight: 15 pounds

Suggested room size: 360 square feet

Filters: True HEPA, "plasmawave", carbon filter, and pre filter

CADR (smoke/dust/pollen): 232/243/246

Speeds: Four speeds and an auto mode

Noise level (dB): 35.3/59.8

Energy use (24 hours): 0.105 kWh

Warranty: Two years limited

Reasons to buy

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Unique technology

Reasons to avoid

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Expensive filters

The Winix 5500-2 performed well, just shy of some of the others on our list. It’s the only device to use relatively unheard of “Plasmawave” technology. The premise behind this is that it creates hydroxyls that easily attach to other molecules to neutralize the air faster. It received an average CADR score of 240 as a result — about the same as the Coway Airmega, and would suit rooms up to 360 square feet. 

If you are someone who needs to see the impact your purifier is having, you're in luck. Included in the design is a light that will glow red, yellow, or green depending on the current air quality. It also includes both auto and night modes to fit your particular needs. Don’t expect cheap filter replacements however. These were on the higher end, costing just under $80 per filter, and you’re recommended to change these over every six months.

Still, this air purifier provides a solid amount of filtration and an auto-sensor that picks up quite hastily. It’s also one of the few devices we tested to come with a remote control, making it easy to program from across the room. Coming only in black however, it will stand out in any minimally designed room. Adding in its beeps and boops, it’s definitely got Star Wars energy.

Read our full Winix 5500-2 review. 

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Best value for small spaces

Specifications

Dimensions: 16.7 x 7.9 x 7.9 inches

Weight: 3.8 pounds

Suggested room size: 190 square feet

Filters: Pre-filter, HEPASilent and carbon

CADR (smoke/dust/pollen): 123/107/96

Speeds: Three speeds and an auto mode

Noise level (dB): 32.5/51.6

Energy use (24 hours): 0.154 kWh

Warranty: One year

Reasons to buy

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Ideal for small spaces

Reasons to avoid

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Wouldn't suit larger rooms

If you're buying an air purifier for a small room, the petite Blueair Blue Pure 411 Auto air purifier is a great fit, suiting up to 190 square feet. It doesn’t have the same strength or flair as its two larger siblings, but that doesn’t make it any less worthwhile. It’s a cute little device and still manages to pack in multiple layers of filtration to keep your air clean.

It uses the same simplistic but easy-to-use controls as the 211+ Auto, meaning you won’t have any trouble trying to set it up or get it going. Just plug it straight into the wall and pick the setting you want by tapping its little noggin. 

It didn’t score as highly in the CADR tests compared to a lot of the other devices, only pulling in an average rating of 109, but it is specifically designed for smaller spaces, so that’s not necessarily a bad thing. It might not clear the air out of your whole house, but it should do wonders in small bedrooms or tight spaces. 

If you want an air purifier for your home office or wherever your pets congregate, this will do the job. Just don’t expect it to put in the same heavy work as larger units and you should be happy with the results. It’s also worth mentioning that the device itself is fairly small and only uses a small amount of electricity compared to its cohorts — add to that it’s pretty quiet too.   

Read our full Blueair Blue Pure 411 Auto review. 

How we tested the best air purifiers 

In order to come up with a list of the best air purifiers, we first researched a number of models on other reviews sites and online retailers to identify some of the more popular models. We then narrowed our list down to 10 air purifiers that we decided to test for this roundup. Testing involved two steps: Lab tests and in-home tests.

Laboratory testing

We compared the CADR of each air purifier to get an accurate representation of the performance. If a CADR rating was not supplied by the manufacturer, we sent it off to a lab to get our own rating — we used SGS IBR Laboratories for this test. The lab calculated the CADR for each pollutant by using the AHAM AC-1 testing method, which involves placing each air purifier in a test chamber and measuring the rate at which it reduces dust, smoke and pollen from the atmosphere. Once you have these figures, you can then calculate the recommended room size for the air purifier. 

This is a widely recognized testing protocol for air purifiers, and one of the few ways with which you can compare performance. For those brands that already provided a CADR, we checked they had the certificate to prove it. That way, we made sure each device got the same treatment. It should be noted that though a device may have a low CADR score, it doesn’t necessarily mean that it’s a bad air purifier. But, this does mean it will struggle in larger rooms.

In-home testing

We then conducted a home test separately to compare the design and ease of use of each air purifier in a real world environment. For energy, we hooked up each device to an electricity usage monitor and ran it for a full 24 hours. To figure out the noise output, we used a decibel meter and ran the purifiers at a set distance of three feet away on both the lowest and highest possible fan settings. We also took an ambient room reading to make sure that the fan noise was not being overpowered by the outside world.

We considered all kinds of factors as part of these in-house tests, from the length of the cord to the plug, to whether the model oscillates. The overall set up and the clarity of the manuals was taken into account as well. With all of this, we were able to create a scoring system to summarize the overall experience. Once all these scores were totted up, we got the average ratings that you see above.

Why are there no Dyson air purifiers in our list? 

We tested the Dyson Pure Cool TP01 air purifier to the same standard as those above, and unfortunately it did not deliver a comparable standard of performance. Our lab tests revealed a CADR of 71.7 for smoke, 68.5 for dust and 72.8 for pollen. These were the lowest CADR scores of all of the air purifiers we tested, with only IKEA’s FÖRNUFTIG air purifier coming close. 

In accordance with these ratings, the Dyson Pure Cool TP01 is recommended for room sizes up to 111 square feet, which is minimal and impractical for most homes. It’s certainly appealing for its unique appearance and modern design, plus it offers some useful features such as a separate remote control and 10 fan speeds. 

However, considering its price of $399.99, we were expecting more in terms of features. There’s no auto setting, which most air purifiers offer nowadays. This allows the air purifier to adjust its fan speed in accordance with the current condition of the air. Without it, you need to adjust the speed manually and potentially waste more energy than necessary. There’s also no smart connectivity or night mode, which is a big disappointment — you need to upgrade to the TP02 model ($499.99) to get all of the above. The Blueair Blue Pure 211+ Auto costs less by comparison, and comes with an auto as well as a night mode. 

As a result, the Dyson Pure Cool TP01 didn’t make the cut, and missed featuring in our best air purifiers list. It’s a great-looking fan, but we wouldn’t recommend it as an air purifier based on the CADR results.

In response to this result, Dyson issued the following statement: “CADR is a measurement of how fast a purifier can clean the air in a small, controlled chamber that has one sensor and a fan to circulate the air. Dyson feels that assessing purification performance by the CADR test alone can sometimes be misleading to consumers because the numerical result is unrepresentative of performance in a real-world environment. Our philosophy is that to truly purify a whole room properly a purifier needs to automatically sense pollutants, capture them effectively, and project clean air to every corner of a large room, representative of real homes. We champion testing that evaluates all three aspects of purification performance rather than focusing solely on speed. Dyson engineers spent years developing such a test (that we call the POLAR test) that more accurately represents a real home to assess how well purifiers clean the entire room. Based on the POLAR test, Dyson Purifiers are rated ‘Excellent’ as are some others available on the market. An air purifier achieves an 'Excellent' rating in the POLAR test if it can reduce PM2.5 particle concentration below 12 μg/m3. This is based on the US EPA's 2012 annual PM2.5 exposure standard.”

CADR Results

Air purifier sales and deals 

Want to invest in a new air purifier? Check out our air purifier sales and deals page first to grab a bargain. Some of our favorite brands have made an appearance, so it’s worth keeping an eye on.   

Is an air purifier actually worth it?

While air purifiers are designed to neutralize and sanitize air pollution, its performance and worth depends on the model you own. Not all air purifiers are suited to remove every allergen, so it's important to check the product description for a clean air delivery rate (CADR). The higher the CADR, the most effective it is of trapping airborne particles. Similarly, air purifiers with a high-efficiency particulate air (HEPA) filter is a good indicator of having a high CADR. In any case, air purifiers are much more effective than houseplants when it comes to cleaning your air.  

If you find an air purifier with a proven performance in terms of CADR and its suited to the allergens you want removing, you've got the best chance of it making a difference to your home environment. However, if you want to see the actual impact your air purifier is making, you can always opt for a model which displays live data, either on the air purifier or on your phone, such as the Blueair HealthProtect 7470i.  

What exactly do air purifiers do?

If you want to know how do air purifiers work, essentially each utilizes a powerful fan that sucks in air to go through one or more filters (HEPA). These filters trap and neutralize particles and pollutants as air passes over them before the air is recirculated. Some air purifiers also have ultraviolet filters and use light to destroy smaller molecules such as mold and bacteria.

If you want to go above and beyond, also check out our tips for reducing allergens in your home.

How to choose the best air purifier for you

If you’re buying an air purifier, there are several factors to consider. First, you want one which is simple to operate, with enough fan speeds to suit your needs. You also need one which will suit you space and work effectively — take a look at the suggested room size and CADR figures for guidance. Generally speaking, the higher the CADR, the better, although it may not be necessary if you’re purifying a small room. It’s also useful if your air purifier can display the live quality of the air, and adjust automatically to it — that way you don’t have to keep changing the settings yourself. Night modes are handy as well if you intend to use the appliance as you sleep.

CADR ratings

The effectiveness of an air purifier can be measured by the CADR (Clean air delivery rate). This number reveals its performance depending on a particular room size. The higher the number, the better it is at clearing airborne particles and the more effective it is at cleaning a larger space too. 

The numbers translate to how many cubic feet of air the purifier can clean per minute. The standard goal is to clean a full room’s worth of air in 15 minutes. So, for instance, a 300-square-foot room would need an air purifier with a CADR of 200 or so, assuming ceilings were 10 feet high and any doors and windows were closed. 

Some air purifiers come with different CADRs for smoke, pollen and dust, so you can see which it is most effective for. Not every purifier is tested using the CADR rating system, but real-life reviews can give you a sense of a device's effectiveness if a rating isn't available. 

Here are the minimum CADR ratings the Environmental Protection Agency recommends by room size:  

Filter types

In general, you'll want to look for a purifier that uses a true high-efficiency particulate air (HEPA) filter. 

Government agencies and professional groups, including the EPA and the American Lung Association, recommend True HEPA filters as the standard for air purification. These filters trap 99.97% of particles that are at least 0.3 microns in size. 

Some devices have HEPA-type filters, which work similarly but aren't held to the same performance standards. The IQAir HealthPro Plus uses a HyperHEPA filter, which is believed to capture even smaller particles than a True HEPA filter. 

Your purifier will likely also come with a pre-filter (some you can clean, some you have to toss after a few months) that catches the big stuff like pet fur and human hair before it reaches the main filter. 

Some devices have additional filters, like carbon or charcoal filters, that trap the petroleum-based gases known as volatile organic compounds (VOCs). Carbon filters also act as natural deodorizers, which makes them suited for the kitchen, too. 

Noise levels

Air-purifier noise levels range from nearly silent to steady humming, like an AC unit. Depending on the fan speed you're using and where you're placing your purifier, you may prefer a quieter device.

Many of us aren’t aware of the added costs when running an air purifier. Firstly, you should consider the cost of replacement filters, then there’s the energy needed to power the appliance on a regular basis. In terms of the filter replacement, some models are fitted with filters which can last for years, but can be very expensive to replace. Whereas others can be cheaper, but a replacement is needed much more often. To calculate the actual cost, you need to balance out the frequency of changing the filter with the cost per filter. OneLife’s new air purifier never needs its filter replaced if you really want to save!  

You should also take energy consumption into account. Some of the best air purifiers in our list are Energy Star Certified and these generally will save money in the long term. Bear in mind that different speeds and settings will affect how much energy it uses though.

If an air purifier is designed to reach a large room and it uses a powerful fan to do so, it is likely to consume more energy than a smaller model, although efficiency can vary. One setting worth looking out for is an ‘Eco mode’ — this should save on energy use and makes the product more sustainable in operation.

Extra features

Some features are more nice-to-have extras than absolute requirements. In general, pricier purifiers come with more features, such as filter indicator lights, dimmable lights and programmable timers. 

Only one of the devices we recommend (the Winix 5500-2) comes with a remote control, but we're not convinced that this adds a lot of value to the machine. 

Do air purifiers help with Covid?

Although there haven’t been any specific air purifiers tested against the Covid-19 virus, the CDC recommends most top-rated air purifiers have efficient filters capable of capturing pesky, particles similar to coronavirus, and “can help prevent virus particles from accumulating in the air in your home”. 

Should I get a smart air purifier?  

Some modern air purifiers, such as the Blueair Health Protect 7470i, can be connected to the Wi-Fi and linked to an app on your smartphone. In doing this, you can control the air purifier remotely, including changing the fan speed or setting a schedule. For some air purifiers, the app will also breakdown the quality of the air and let you monitor it more precisely. 

This can give you a much better understanding of what’s in your air and you can see the effect the air purifier is having on it too. Using the Dyson air purifier app for instance, you can see the different levels of particulate matter as well as any volatile organic compounds (VOCs) and nitrogen dioxide. This is usually displayed in a chart form so you can see where there’s been an increase in any air impurities. 

This can be a useful feature to have, particularly if you want to better understand your air and want to source where your allergies are coming from. It’s also nice to see the evidence that the air purifier is making a difference. 

Some apps will even display what the air is like outside as well, so you know not to leave when the pollen count is high or the general air quality is low. 

Steven Asarch is a writer and editor who lives on Twitch and YouTube. After graduating from Baruch College, he wrote for IBT Media,  Newsweek and Insider. In 2021, he executive produced the docu-series "Onision in Real Life" on Discovery +. As someone always looking to have the best smelling apartment possible, he's made it his mission to find the best air purifiers out there. His home has since become an air purifier haven, having stored and tested ten models for over three months. You could say he now knows everything there is to know about air purifiers, and what separates the good from the best.