What’s the best air purifier?
The oft-overlooked aspect of health is the air that we breathe at home. While we all have an idea of how bad the air outside can be, particularly for those of us living in cities and dealing with pollution, the air inside can be just as toxic. From harsh cleaning chemicals to pet dander and pollen coming in, the air at home may not be as clean as you’d expect.
The answer is to get an air purifier. These devices are basically fans that suck in dirty air, clean it in a filter and pass out nice clean air the otherside. From reducing allergy incidents to making it easier to breathe and sleep, an air purifier can make a massive difference to your life. Here, we’ve rounded up the best of the models that we’ve tested. We’ve included a variety of products, from the simple, dumb models that simply suck in air to smarter models that can monitor the air automatically, ramping up when harmful particles are detected, so there’s something for every budget here.
For convenience, we’ve listed our choice of the best air purifiers below, but you can keep reading this article to get the full lowdown on each model.
- Best overall air purifier: Dyson Pure Hot+Cool
- Best budget air purifier: Dimplex DXAPV3N
- Best air purifier for fast cleaning: Blueair Classic 405
- Best air purifier and fan: Dyson Pure Cool Tower
- Best air purifier for large rooms: Vax Pure Air 300 Air Purifier
How we choose the best air purifiers
The quality of air cleaning is the key feature of an air purifier. All air purifiers are capable of removing particulate matter (PM) from the air, which are the tiny particles responsible for triggering allergies, such as hay fever and asthma.
To demonstrate the quality of cleaning, the majority of air purifiers come with Clean Air Delivery Rate (CADR) ratings for smoke, pollen and dust. The higher the score, the better the performance. And, the individual ratings help you choose the right purifier for your needs.
However, not all manufacturers quote CADR ratings and, instead, quote the percentage of particles below a certain size: the higher the percentage and the lower the quoted particle size, the better.
Some – but not many – air purifiers are capable of removing Volatile Organic Compounds (VOCs) from the air, too. These are harsh chemicals that can be found in everything from old furniture to cleaning sprays.
To test an air purifier’s performance, we use a three-second burst spray from a can of insecticide – a source of particulate matter and VOCs – directed into the middle of the room. With the air purifier placed in a corner running at maximum, we time how long the air takes to return to normal, using a separate air-quality monitor.
We also test the sound levels of purifiers, running at minimum and maximum speeds from a distance of 1 metre.
1. Dyson Pure Hot+Cool
The perfect all-rounder for every time of year
Once the air filters have been clipped into place, the Pure Hot+Cool can be controlled using the remote control that magnetically attaches to the top of the fan blade. You can set a temperature, put the fan into cooling mode and cycle the display to see how clean your air is and what’s causing any pollution.
Cleverly, the fan can also be connected to your Wi-Fi network, so you can control it entirely through the Dyson Link app or by using an Amazon Alexa device.
As a fan (heating and cooling), the Pure Hot+Cool is brilliant: it’s efficient, quiet and has a gentle air stream. It’s also a very good air purifer, too, sucking our test allergens out the air quickly, returning our room to a safe state, which the fan’s auto mode maintains. Cleverly, this fan can also direct its airflow backwards out of the rear of the fan, so you can use it as an air purifier in the rare times where you don’t want a blast of hot or cold air. As a product that you can use all of the time, there’s nothing like this, making the Dyson Pure Hot+Cool our air purifier of choice.
Filter type: HEPA/Gas, Filter life: 1 year, Size: 700 x 270 x 200 mm, Max room size: 400 square feet, Number of speeds: 10, Auto mode: Yes, App control: Yes
Read our full Dyson Pure Hot+Cool review
2. Dimplex DXAPV3N
A cheap and powerful air purfier for smaller rooms
Not all air purifiers are giant boxes, as the Dimplex DXAPV3N demonstrates. This is a small box that’s designed to fit on a desk. It can clean an area up to 28m2, making it suitable for smaller rooms. It’s also one of the least expensive HEPA-filter purifiers available. To get the price down, the DXAPV3N is a rather simple product. It can’t display the current air quality; there’s no remote control; and there’s no sleep timer. There’s a carbon filter built in, designed to neutralise odours, and it emits negative ions to help reduce the risk of some viruses.
The operation is simple, using the two-speed dial on the side. At the maximum setting, I measured noise at 49dB; switching to the low-power setting, sound dropped to 47.4dB – which is still fairly loud. It’s a shame that there isn’t a quieter night-time mode. Power efficiency is pretty good, with the DXAPV3N drawing 24.8W at maximum power, dropping to 15.5W at minimum.
At maximum setting, the particulate matter from our spray of insecticide took just under five minutes to return to normal levels. That’s comparatively slow, and confirms that this really is a product for a smaller room. The official CADR ratings bear this out, with low ratings for smoke, pollen and dust: CADR ratings: 80 (smoke), 89 (pollen), 78 (dust). Each HEPA filter should last for around 2000 hours. There’s no warning to tell you when the filter needs replacing, so regular manual checks will need to be made.
If you have a small office or bedroom, the DXAPV3N could be a good choice. For larger rooms or more effective purifying, the Vax Pure Air 300 Air Purifier or HoMedics Brethe Air Purifier are better choices.
Filter type: HEPA and Ioniser, Filter life: 6 months, Size: 333 x 133 x 248mm, Max room size: 28 square metres, Number of speeds: 1, Auto mode: No, App control: No
3. Blueair Classic 405
An extremely powerful air purifier that’s ideal for dealing with smoke
To look at the Blueair Classic 405 doesn’t look like much: it’s a rectangular, plain-looking box. Get past the exterior, which is easy to do when you consider that you’ll likely tuck this product out of the way, and there’s a lot to like here, as this is one of the most powerful air purifiers that we’ve tested.
Shipping with this model is the SmokeStop filter, which is designed specifically to capture smoke particles, which is handy if you live in a house where people smoke. Each filter lasts around six months, after which it needs to be replaced for a whopping £105. However, if you can opt for the standard HEPA filter, which does the same thing but doesn’t capture gasses or volatile organic compounds (VOCs) for £65.
The Blueair Classic 405 has some of the best Clean Air Delivery Rate (CADR) ratings, with test results of 476 (Smoke), 510 (Dust) and 510 (Pollen). These suggest that this air purifier is designed for people with particularly bad allergies. In our own tests, we found that the Blueair Classic cleaned out the smoke from a smoke pellet in 5m 41s – the fastest that we’ve seen.
Control of the purifier is simple via the control panel on the front, which lets you set one of three speeds. You can also hook the purifier up to your Wi-Fi network and control it via your phone. This model doesn’t have an air quality sensor built in, so there’s no auto mode. If you have an air quality sensor, you can use IFTTT to control the purifier automatically. The more expensive Blueair Classic 480i does.
If you suffer from allergies or are in a house where people smoke, the high-performance Blueair Classic 405 can easily clean anything up to a 40-square-meter room.
Filter type: HEPA, Filter life: 6 months, Size: 590 x 500 x 275mm, Max room size: 40 square metres, Number of speeds: 3, Auto mode: Yes (via optional Blueair Aware), App control: Yes
Read our full Blueair Classic 405 review
4. Dyson Pure Cool Tower
A powerful air purifier that is a top fan for the warmer months of the year
If you want a device that’s useful practically all year round, you need the Dyson Pure Cool Tower. This model looks and acts like other Dyson fans, providing you with a stream of cool air when you need it. However, the built-in air purifier can be used to clean your air, too. With this model, the airflow can be redirected out of the back of the fan, so the purifier can run in winter without blasting you with cold air.
Cleverly, the front display shows you the current air quality, so you can see when your air is dirty and when it’s clean. Put the fan into auto mode and it will ramp up when the air needs cleaning, but turn off when all is good. Throw in app control and Amazon Alexa support and you’ve got a quality air purifier and fan combination that more than justifies the comparatively high price.
Filter type: HEPA\Gas, Filter life: 1 year, Size: 1054 x 223 x 117mm, Max room size: 450 square feet, Number of speeds: 10, Auto mode: Yes, App control: Yes
Read our full Dyson Pure Cool Tower review
5. Vax Pure Air 300 Air Purifier
It might look like a dustbin, but this air purifier is powerful and perfect for larger rooms
Looking like a fancy bin with an ashtray for smokers on top (760 x 320 x 320mm), the cylindrical Vax Pure Air 300 Air Purifier is attractive in glossy white plastic and is easy enough to place out of the way. It has a HEPA filter – designed to last three to six months, depending on usage – and an ionisation option. The purifier’s front panel is dominated by simple touch controls that let you power on the Air 300, control the fan speed, use the timer, and toggle the ioniser function. These options are replicated on the slim-line remote control.
The big indicator light on the front changes colour to display the current air quality, moving from green through amber to red. At minimum fan speed, I found the Vax Pure Air 300 ran at 35.9dB and a more intrusive 62.1dB at max. The night mode cuts the status lights and drops fan speed to a lower level, with sound falling to a quiet 33.4dB. Although it was still audible, you could easily sleep through its low-level noise. Power efficiency is excellent, with max power drawing a peak of 53.8W, and the minimum setting just 7.2W
Most people will find it easiest to run the Air 300 Air Purifier in automatic mode, with the device choosing the best fan speed to deal with current air conditions. I found that the fan never fully turned off, which is a little disappointing. Still, there’s a timer option – hourly increments of between one and eight hours – if you want the Air 300 to power down.
Regarding effectiveness, the Air 300 has high CADR ratings:428 (smoke), 392 (pollen), 278 (dust). In our synthetic test, it cleared the particulate matter from of our insect spray in 1min 8secs.
If you want a powerful all-rounder, this is the model to buy, and it’s suitable for rooms of up to 120m2. Those who want something quieter should buy the Philips Air Purifier Anti-Allergen with NanoProtect Filter AC3256/30.
Filter type: HEPA, Filter life: 6 months, Size: 760 x 320 x 320mm, Max room size: 120 square metres, Number of speeds: 5, Auto mode: No, App control: No
How do I buy the right air purifier?
Best air purifiers – What can air purifiers do?
Air purifiers use a fan to pull in dirty air at one end, remove pollutants, and output clean air at the other end. The exact pollutants that can be cleaned depend on the technology used. All of the air purifiers we’ve tested here use a HEPA filter, which will capture a minimum of 99.97% of airborne particles 0.3µm in size. Also known as particulate matter, these particles can penetrate your lungs causing respiratory problems, particularly in allergy sufferers.
Particulate matter sources include dust, with cleaning likely to disturb dust and throw it into the air, pet hair and dander, smoke and pollens. HEPA filters are no good where dust has settled, since the filters can remove only airborne particles. In other words, you still need to clean effectively. HEPA filters also have a lifespan, after which they’ll need to be replaced. The exact timing will depend on the air purifier and how dirty your air is, but expect to buy a new filter between three months and 12 months of operation.
Volatile Organic Compounds (VOCs) are harmful chemicals that are often found in cleaning products, paints, and some beauty products. VOCs are also found in some manufactured products, such as synthetic carpets and old furniture. Most air purifiers can’t touch these pollutants; those that can, can’t filter all VOCs.
Instead, you’re better off with an air monitor, such as the excellent Foobot, to monitor your home to see what’s giving off VOCs. Where possible, switch to less harmful products. Some models of air purifier also have an ionisation option. These use negative ions, which causes particles to stick to surfaces – such as wall or floor. Ionisation has been shown to reduce the risk of some viruses. Ionisation on its own isn’t particularly effective, so always combine with a proper air purifier.
Best air purifiers – What else should I look for?
All air purifiers use a fan of some description, so look for one that runs quietly enough for your intended use. We measure sound at maximum and minimum settings to help you choose. An automatic mode that ramps up the fan when the purifier detects dirty air is useful, as you can leave the purifier to do its job. You need to match the air purifier you buy to the size of room or space that you want to keep clean. Purifiers are rated by the square metre, so buy one that’s big enough.
Finally, you can look out for the Clean Air Delivery Rate (CADR), which tells you how effective the purifier is at different types of allergen, compared to introducing clean air. For example, an air purifier with a CADR score of 190 for dust particles is as effective as adding 190 cubic feet of clean air per minute. In short, the higher the CADR rating for each type, the better. And, CADR scores are comparable across all products, helping you make the right choice.
CADR has three main ratings to help you decide: smoke uses very small particle sizes of 0.09 to 1µm; dust has particle sizes of 0.5 to 3µm; and pollen uses particle sizes of 5 to 11µm. It’s best to choose your air purifier based on how effective it is at the pollutant you want to remove. Hayfever sufferers, for example, should choose an air purifier that’s efficient for pollen removal.
Finally, since air purifiers come in different sizes, the CADR rating should equal (or exceed) 2/3 of your room size in square feet. A 135-sqft room would need CADR ratings of 90 or above, for example.