If you want to breathe cleaner air in your house, getting an air purifier is a solid investment. Air purifiers with a high-quality HEPA filter have been proven to reduce the amount of pollution in the air, although they’ll never remove it all entirely. We’ve reviewed some of the best air purifiers around, so you can find the one that’s right for you. While we can’t conduct lab-style testing to verify manufacturers’ claims, we can tell you how they work, which types of pollution they work best against, if they’re noisy or quiet, if they’re easy to move around and if we think they made a difference to air quality. Some of the air purifiers are dedicated appliances, others are multifunctional and also heat or cool the air, or dehumidify it. Some have displays for air quality information and others are app-connected. All of them have been taken home and tested in our homes.
If you want more information on home air quality, we’ve got articles on how to monitor and how to improve it. And if you want a bit more advice on what to look out for in an air purifier, see which pollutants they can handle and find out what common terms mean, see our buying advice after the round-up.

How to buy an air purifier

If you’re mulling over different air purifiers, there are some factors you might want to consider before your part with any cash. No air purifier will be 100% effective at cleaning the air, but they can make a noticeable difference to people with allergies and hay fever. They are also handy for reducing cooking odours, as well as lingering paint and cleaning product smells.

				Three air purity measures					   					Easy to move, thanks to its wheels					   					Smart features					 

				No remote					   					No handles					   					No ioniser

Jya states that the Fjord will deal with zones from 31m2 to 54m2. Its Clean Air Delivery rate (CADR) is 450m3 an hour, and for the TVOC CADR, 150m3 an hour. It has a touchscreen control panel, with a display that’ll show you the air quality in terms of either PM2.5, PM10, or TVOC. It also has smart features. It’s Apple Homekit, Google Assistant and Alexa compatible. Also, via the app, you can monitor your air quality in the longer-term, with daily, weekly and monthly graphs. There are four operation modes, including a whisper quiet (18.8dB(A)) sleep mode.

				Sleek, premium design					   					Impressive cooling capabilities					   					Protects from gases and pollutants in the air					   					Quiet performance					 

				No onboard controls					   					No companion app or other smarts

Dyson claims that it can generate up to 290 litres of purified air per second. In typical Dyson fashion, however, the brand has issues with Clean Air Delivery Rate (CADR) as a measurement of how well air purifiers work in real life. So it’s hard to be sure that all of the air that it’s moving is being effectively cleaned and it’s difficult to compare it against rival appliances. However, in our test, it effectively cleaned a room of smoke after cooking. It has a replaceable glass fibre HEPA H13 filter to filter toxic and smelly VOC gases, as well as 99.95% of particles as small as 0.1 microns. And the whole chassis meets the HEPA H13 standard to keep trapped pollutants inside. The colourful on-unit display shows PM 2.5, PM 10, VOC and NO2 depending on what’s detected in the air. It’s also a very effective fan, which you’ll appreciate when summer comes. There are no smart features, but it comes with a remote. Our one design bugbear is the lack of controls on the unit itself, which would be handy. You can also check out our reviews of the Dyson Pure Cool Tower and the Dyson Pure Cool Me.

				Remote control					   					UV sanitiser					   					Ioniser					 

				Not smart-enabled					   					No fan adjustment on sleep mode					   					No wheels

There’s a prefilter for particles one micron in size and larger: dust, hair, and dander. The HEPA HII filter catches particles above 0.3 microns in size and 95% to 99% of particles below 0.3 microns. Next, there’s an activated carbon layer. The final layer is cold catalyst filtration, to control VOCs (harmful and smelly gases). It’s also equipped with a negative ion generator and a UV light. It will clean spaces from 150-550ft2, so 14m2 to 51m2, and it will clean up to 550ft2 every hours, up to 1650 ft2 in three hours. There are no smart features but it comes with a remote control. The unit itself also has a light indicator to give at-a-glance air quality information, as well as a numerical indicator.

				Small					   					Quiet					   					Portable					   					Good range of settings options					 

				Better suited to smaller rooms					   					No smart features

It has a clean air delivery rate (CADR) of 176 cubic feet per minute or 300 cubic metres per hour, and an effective range of 273 sq ft or 25.4m2. This means it’s good for smaller spaces only. We think it would work best beside your bed or desk to help with symptoms of hay fever or dust allergies. It won’t disturb your sleep or work either, as it’s very quiet in use, with an operating volume of 20-54 dB. On its lowest setting, that’s very quiet indeed. It has an H13 True HEPA Filter, which will trap 99.97% of particles down to 0.3 microns, an ultra-fine nylon pre-filter to capture larger particles, and an activated carbon layer which will get rid of bad smells, smoke and harmful gases like VOCs. This makes it a good all-rounder. It doesn’t have smart features, or any kind of display beyond a coloured LED to indicate air quality.

				Attractive					   					Portable					   					Good for personal use					 

				No air quality display screen					   					No remote control					   					No smart features

It has six stage filtration, including a HEPA H13 filter and an activated carbon layer for gaseous pollutants. There’s an optional UV light to help to sterilise the inside, as well as an ioniser. Its CADR rates are 191 m3 per hour for smoke, 190m3 per hour for dust and 205m3 per hour for pollen. It’s easy to use as well, with a straightforward control panel and corresponding indicator lights. You can set a timer to switch it off after 4, 8 or 12 hours, turn on a night light and dim the indicator lights in night mode. On its lowest setting, it’s only 33dB, so it would be ideal to stop a room getting stuffy while you sleep without disturbing you.
But there’s no display to show pollution levels, so if you want to monitor your home air quality, it won’t be right for you.

				Can cycle clean air multiple times an hour					   					Compatible with H14 filters					   					UV-C lamp and negative ionisation					 

				Loud at faster fan modes					   					Can’t disable annoying chime					   					AI mode is exclusive to Zigma app

It has a 5-in-1 filter system with an H14 HEPA medical-grade element that filters up to 99.97% of fine dust, pet hair, mites, air pollution, PM 2.5 (pollutants smaller than 2.5 microns) and ultrafine particles under 0.3 micrometres. That’s backed up by an activated carbon filter that helps remove lingering smells like pets, kitchen smoke, cigarette smoke as well as neutralising formaldehyde and other harmful substances. Plus, there’s a UV-C LED bulb that aims to kill viruses and bacteria that pass through the appliance. The Aerio 300 has a Clean Air Delivery Rate (CADR) of up to 330m³ an hour, allowing it to clear up to a 1580 sq ft space within an hour. It also has smart features, and it’s reasonably priced as well.

				Powerful and quiet					   					Easy to use					   					Smart features					   					Complete air filtration					   					For large rooms					 

				Not an attractive appliance					   					Two expensive filters to replace

And there’s a lot to like about it. It has a three-stage filter, with a pre-filter for pet dander, hair and dust; a HEPA 13 filter for airborne particles down to 0.3 microns, including viruses, pollen, dust mites and mould; and an activated charcoal layer to help with smoke, VOCs and unpleasant odours. In our home tests, it cleared the kitchen of smoke quickly. It also has two air intakes equipped with filters for pulling in air from two directions. Other benefits are its quiet operation, its mode options and a clear display both on the appliance itself and in the app. However, it is not an air purifier that will blend in to your home. Its design seems to draw attention to itself, and with an ugly appliance, that’s not a good thing. Two filters also means twice the number to replace.

				Quiet					   					Easy to use					   					Portable					   					Dual use					 

				Pricey					   					Featureless design

We tested the 25L Arete One, which can extract up to 25L of moisture from the air per day at 30°C and 80% relative humidity, which is high performance. It has an easy-to-read control panel but what makes it even easier to use is that it will intelligently adjust to the moisture level in the air and you won’t need to tweak it at all. It’s very quiet in operation at 42dB. You can also use it in air purification mode, without the dehumidifier. It’s equipped with a washable dust filter, plus an optional medical grade H13 HEPA filter and charcoal filter. If you want an air purifier but your home has problems with damp or condensation, or if the air gets damp when you air dry clothing, the Arete One is a solid, dual-function option. But unless you have a serious mould problem, you can opt for the smaller size and save some money.
Here are some questions to consider before you buy.

How large is the space you want it to clean?

Most air purifier manufacturers will give an optimum room size that their air purifier can clean. This is a good guide, although it may not be perfectly accurate. The key thing is to ensure that the air purifier has enough capacity to clean the air in the room you’ll most often use it. If you’re not looking to clear an entire room of paint fumes or cooking odours, but just want to refresh the air around your desk while you work or your bed while you sleep, you may just need a personal air purifier. In this case, something like Dyson’s Pure Cool Me could be a better option.

What is CADR?

Most air purifiers will state their Clean Air Delivery Rate (CADR), a metric to measure air cleaning efficiency. This is the amount of air, in cubic feet per minute, that has had all of the particles of a specific size removed. So an air purifier will have a separate CADR for particle sizes corresponding to smoke, pollen and dust. CADR ratings were created by the American Association of Home Appliance Manufacturers (AHAM) and are considered the industry standard. You can use a CADR rating to compare how efficient different air purifiers are, and what size room you can use them in. In perhaps typical fashion, Dyson doesn’t agree with this rating system, so its appliances don’t use it. This makes it difficult to compare Dyson air purifiers with rivals, although when we have tested Dyson air purifiers, the experience has been positive.

Which pollutants can a purifier remove from the air?

Good air purifiers tend to have multi-layer filtration systems, to deal with different types of air pollution. They will have some or all of the following forms of purification:

A pre-filter: this filters will help to remove hairs and larger forms of particle pollution from the air. A smaller particle HEPA filter: this will help to filter out larger particles that may affect hay fever and allergy sufferers and very small particles of pollution, which can be harmful to the lungs. An activated carbon layer: this will help to remove VOCs (volatile organic compounds) from the air. These chemicals are a gas at room temperature and can be toxic: you may see this class of pollutant referred to as TVOC – total volatile organic compounds. Typically they come from solvents, cleaning products, personal care products, new furniture, paints and aerosols used around the home.UV light: if there’s a UV light, it will be inside the purifier and it won’t shine out. It’s there to prevent bacteria from growing inside the appliance, in areas that may be damp or warm. Ioniser: an ioniser will create a static charge that affects airborne particles and causes them to fall out of the air onto surfaces where they can be wiped or vacuumed up.

What is a HEPA filter?

A HEPA (High Efficiency Particulate Air) filter is the industry standard. HEPA filters must remove at least 99.95% or 99.97% (depending on the legislation in your region) of particles from the air down to at least 0.3 microns in size. If a product says it has a “HEPA-style” filter, or uses a similar phrase, it probably means that the filter does not meet HEPA standards.

How often should you change the filter?

Air purifier manufacturers will give you a rough estimate of how often you need to change the filter. It will likely last you around six months. But if you’re decorating your home or have an open fire or wood-burning stove, you’ll need to change it more often. Some purifiers will have an indicator to let you know when a filter needs to be replaced, although it’s not always clear if this is after a set period of time, or in response to use.

How noisy will it be?

Moving a lot of air tends to be a noisy process. A really effective air purifier cleaning the air of smoke or fumes is unlikely to do it silently. Manufacturers usually display decibel ratings for different modes, and some purifiers will have sleep modes that are very quiet.

Does it have smart features?

Some air purifiers have a full set of controls on the appliance. Others (Dyson, again, we’re looking at you) have very few controls on the purifier itself, instead relying on a remote control. Some air purifiers are app-controlled. The advantage of this is that, not only can you use your phone as a remote control, but you will usually get much more information about air quality in the app, often in the form of a graph showing the change in air quality over a day, a week or a month. Emma is Home Tech Editor at Tech Advisor. She covers everything from kitchen appliances to smart home devices, from floor care to personal care to air care technology. She’s particularly interested in environmentally conscious brands and products that save people time and money.