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Home & garden.

Updated: 24 Jun 2022

Best air purifier 2022: Which? Best Buys and expert buying advice

Choose the best air purifiers for you with top recommendations and buying tips
Hannah Fox
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The best air purifiers will do a great job of cleaning the air in your home. But there are also plenty of air purifiers that struggle to tackle common household allergens, including some expensive models. Read on for our Best Buy recommendations and expert buying advice.

'Air purifier' is a popular term for these machines, so that's how we refer to them, but 'air cleaner' is more accurate. These machines don't leave you with sterile or completely pure air, but they can make it cleaner. 

Our tests have found that a good model will improve the air quality in your home quickly without making too much noise or using too much energy. Poorly performing air purifiers will be significantly slower, trap far fewer particles in the same time period, and potentially make more noise and use more energy in the process. 

Some air purifiers are great all-rounders, while others are better at tackling one type of pollutant than another. If you've got hay fever, for example, your priority might be picking a model that's great at trapping pollen.

Scroll down to find out if an air purifier is right for you, the types available and how much you should expect to pay. 

Already know what type you want? Check all our air purifier reviews to discover the models that will do a great job of cleaning the air in your home. 

Best air purifiers for 2022

We've put the most popular air purifiers on the market through our tough lab tests. Log in or join Which? to reveal our Best Buys in the table below.

  • 85%
    • best buy

    This air purifier does a great job of clearing pollen particles from the air. So, if hay fever routinely ruins your summer, it could really help you. It’s our third best air purifier for trapping pollen, and our joint-top air model overall. It’s also fairly cheap as far as air purifiers go.

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  • 84%
    • best buy

    This air purifier did a terrific job of removing dust, pollen and smoke from the air in our tests. It has an LED digital display, a timer, a night mode, an automatic mode and three fan speeds. It’s also controllable via wi-fi from a smartphone app. It is expensive, though.

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  • 80%
    • best buy

    We were hugely impressed with this air purifier; it aced our dust, pollen, and smoke removal tests, and it’s energy efficient, too. Just be aware that it’s noisy on the max setting.

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Table last updated May 2022

The pollutants we test for

We test with dust, pollen and smoke particles, as these are common household allergens. We can't specifically test with traffic pollution particles, another cause of concern, but an air purifier that performs well in our dust tests is likely to also do a good job of trapping harmful PM2.5 particles found in traffic pollution, which are of a similar size to dust at 2.5 microns (µm). 

Particles are only one aspect of traffic pollution, though. Gases such as NO2 (nitrogen dioxide) are also an issue and can't be trapped by an air purifier's main filter due to being too small. If you can, buy an air purifier that also has a carbon filter, as these are designed to trap gases. 

Video: how to buy the best air purifier

Watch this video to help you buy the best model for you.

Do I need an air purifier?

An air purifier shouldn't be thought of as a first line of defence against indoor air pollution. Ultimately, generating less air pollution means you'll be breathing cleaner air and contributing less towards national emissions. 

First, where it is possible to do so, eliminate the sources of air pollution in your home, and ventilate.

For example:

  • Minimise your use of products such as chemical sprays
  • Keep humidity under control, so that biological contaminants don't thrive, and employ good hygiene practices
  • Open windows, particularly when you've just carried out an activity that causes pollution. But be strategic about when you do this. If you live near a busy main road, for example, don't open your windows when traffic is at its busiest. 

Check our guide on improving indoor air quality for more tactics to try.

If it's not possible to increase ventilation because your outdoor air quality is poor, say, or you suffer from hay fever and can't leave windows open for long periods in case pollen comes in, then an air purifier could be a good investment, provided you buy the right model. Remember that you'll need to close the doors and windows to the room with the air purifier in, so that you're not giving it more pollution to tackle.

It's also worth keeping in mind that your air purifier will not be able to clean the air throughout your whole property, as it'll come with a maximum room size in which it can do so.  

Our tests show that using an air purifier in your home will reduce the number of pollutants in the air, such as dust, pollen and smoke particles. 

All the models we’ve tested removed at least some particles from the air, but the difference between the best and worst is enormous. In your home, picking one of the worst models we've tested means it would take much, much longer to clean the air. This is not much use if you’re allergic to household dust or pollen and need these pollutants banished fast. 

Best air purifiers: woman with allergies

What features should I look for on an air purifier? 

HEPA filter

A high-efficiency particulate air (HEPA) filter is a type that uses a combination of trapping mechanisms to capture pollutants. These are often made up of a large particle filter, which can be reused and washed, as well as other finer filters, usually including a disposable HEPA filter. 

EU standards state that to use the term HEPA a filter must remove at least 99.95% of tiny particles with a diameter of 0.3μm.  

Keep an eye out for filters with marketing names such as HEPA-type, HEPA-style and so forth, as there's no guarantee they will conform to the same criteria.  

An air purifier with a HEPA filter is more likely to do a good job than those with another type of filter. We’ve reviewed most air purifiers on the market, but if you’re buying one we haven’t reviewed, buy one with a HEPA filter. 

A HEPA filter doesn’t guarantee that an air purifier will be good as there are other aspects to an air purifier that might make it a bad machine. At least one air purifier we’ve tested with a HEPA filter was so disappointing in other respects that we made it a Don’t Buy. 

A HEPA filter won’t tackle odours or gases – for that you'll need a carbon filter.

How to make air purifier HEPA filters last longer 

With some machines (not all), you can clean the filters to extend their lives, which will save you money on replacements. Always follow the manufacturer instructions, though. 

If you do vacuum your filter, go gently. Vigorous vacuuming can damage the delicate fibres. And do it outside, to avoid reintroducing captured allergens to your home.

Carbon filter

For unpleasant smells and gases, including volatile organic compounds (VOCs) from common household products such as cleaning products, you’ll need a carbon filter as well as a HEPA filter. 

This is also sometimes called an activated carbon filter or a charcoal filter. 

Increasingly, most air purifiers, and a few dehumidifiers, come with a carbon filter. But don’t rely solely on it: instead, ventilate your home regularly, as we've highlighted above.

Automatic mode and air-quality sensors

Many models have air-quality sensors. If left on automatic mode, these machines will sniff out pollutants and spring into action as needed. If you've just sprayed deodorant, for example, it will detect a change in the air quality and work harder.  

Often these air purifiers will also give you information on the quality of the air in the room (based on their estimation), in the form of a coloured light on its display. If you've got a smart air purifier (one that is internet connected), you may also get more detailed information sent to your smartphone app. 

Do you suffer from a pollen or dust allergy? Find out which models are best at removing pollen and dust from the air: see all our air purifiers.

woman breathing in

Air purifier timers

Most air purifiers come with a timer, which you can use to set your air purifier to turn on or off after a certain number of hours. That could be handy if you routinely change the settings at the same time each day. You might, for example, want your air purifier to run at high fan speed all day if you're out at work, then at a lower speed in the evening and at night. 

If you're going to use a timer, it's worth bearing in mind that you can't just set an air purifier to run for a few hours each day and expect it to make much difference to your air quality as they're designed to run pretty much constantly. The more often air passes over the air purifier filter, the cleaner the air in your room will be. 

Humidification or heater functions

A couple of air purifiers have other functions, such as heating or humidification. 

The Dyson HP04 Pure Hot+Cool Purifying Fan Heater (£549), for example, can heat or cool a room, while the Dyson Pure Humidify+Cool (£599) can also humidify. 

Dyson is a big-name brand, but our tests have shown time and again that this is no guarantee of a great product – check our Dyson air purifier reviews before you buy.

Smart air purifiers

Smart air purifiers tend to be more expensive, as you'd expect. These can be controlled from a paired smartphone.

Some of the accompanying apps offer other useful features, such as information about the air quality levels in your home, reports on the outdoor air quality in your area and reminders to change the filter. 

Smart air purifiers we've tested include the Blueair 605 and  Blueair Classic 405.

Go to our air purifier reviews to find out which apps and smart functionality we liked best.

How much do air purifiers cost?

Air purifier prices start from around £100 and go up to more than £600. Our tests suggest that, to be confident you're buying one that does a good job of cleaning the air, you’ll need to spend at least £200. Most of our Best Buys cost £300 to £400. 

One of the models we've made a Don't Buy is sold for £320 at time of writing, which is mid-priced for an air purifier.

Spending this much doesn’t guarantee you’ll avoid the duds. One of the models we've made a Don't Buy is sold for £320 at the time of writing, which is mid-priced in the market. So check our reviews before parting with your money.

How much does an air purifier cost to run?

Obviously, the cost of running an air purifier will depend on a number of factors, including how much energy it uses, how often you run it and how much you're paying for energy. 

Depending on the model you have, if you were to run yours for 12 hours a day, every day, it could cost you anywhere between £20 and about £250 a year. For the models we've tested, the average annual cost is £57. That's based on the assumption that electricity is 21 pence per kWh (kilowatt-hour).

Do air purifier filters need replacing?  

Yes. All filters have a lifespan, the length of which depends on how often you use your machine, how often you clean the filter and how dirty the air in your home is. Manufacturers generally recommend that you change your filter every six months, as once it's clogged up it won't be much use. 

Some machines have a filter-replacement indicator light and some send a notification to your smartphone app.   

New filters can cost from about £20 to more than £50, depending on which model you buy.

When buying, it's wise to check if replacement filters are easily available. If you can't get replacements, the filter will eventually clog up and the model will no longer work. Keep this in mind if you buy your air purifier second-hand, as filters may be tricky to get hold of for some older models. 

We do routine checks on the availability of filters for our Best Buys. If we find any that have long-term filter stock issues, we will remove its Best Buy status until and unless the situation is resolved.  

If you’ve bought a second-hand air purifier, read our guide to your rights when buying second-hand goods. 

How to dispose of your air purifier

If your air purifier has reached the end of its lifespan, it's important to dispose of it responsibly, so don't just chuck it in the bin. In most cases, you should be able to recycle a defunct air purifier. Look for the crossed out wheelie bin symbol on your air purifier, as this is an indicator that it can be recycled. 

WEEE logo

Before you recycle your air purifier, remember to check how to dispose of the filter. It’s likely that this part will need to go in your normal household waste, as it’ll contain pollutants (such as smoke, dust or pollen) that it’s been designed to capture.

Depending on where you live, your local council may offer kerbside collection for your unwanted electrical items. You can also visit a recycling centre, but before you go remember to check if you need to take a proof of address or book a slot. 

Find out more about how to recycle your electrical items correctly.

How quiet are air purifiers?

All air purifiers make a bit of noise while in use, but some are far louder than others, particularly on their highest settings. The quietest machines do a very good job of keeping noise to an absolute minimum, both on the lowest and highest setting. 

Some air purifiers have a night mode, which reduces the fan speed and dims any lights so that the machine doesn't keep you awake. If you're not planning to run your air purifier in the bedroom, you might not be too worried about this. 

If you are though (if you have allergies that interfere with your sleep, for instance), you can use our reviews to find the ones that are genuinely quiet on their lowest or night setting vs those that aren't. The difference between lowest and highest settings can be the difference between hardly being able to hear an air purifier and an annoying whine. 

If you've already bought an air purifier with a disappointingly loud night or low-fan mode, try running it in your bedroom all day with the doors closed and switch it off at night. That way, at least the air in your room will be much cleaner at the point you try to sleep.

man sleeping

Unless you can try an air purifier out before you buy, the only way you can tell if it's likely to disturb you or not is to read our reviews.

What is an air ioniser? 

An air ioniser is an alternative type of air purifier. Instead of using a fan or filter to purify the air, as is the case with most air purifiers, an air ioniser does it by electrically charging air molecules.

An ioniser creates negative ions (charged particles) and pushes them into the air where they can attach to positive ions (dust, allergens etc.). After bonding together, the particles become too heavy to float and will drop to the floor or nearest surface, to be cleaned away.

Do air purifiers release ozone? 

Ozone can react with pollutants to alter their chemical composition. If you have a lung condition, ozone can lead to breathing difficulties, wheezing and coughing. Even if you're healthy, ozone can irritate your airways. 

You don't need to worry about air purifiers that use a HEPA filter alone to clean the air. However, ionizing air purifiers, or products that use UV lights, could give off ozone because of their electric charge. If you can, look for one that states that it doesn't create ozone. And you should avoid any that describe themselves as 'ozone generators'.