Best air purifiers 2024: Which? Best Buys and expert buying advice

The best air purifiers will do a great job of cleaning the air in your home, but there are also plenty that struggle to tackle common household allergens, including some expensive models. 

A good model will improve the air quality in your home quickly without making too much noise or using too much energy, and our tests measure all of these. Poor-performing air purifiers will be significantly slower, trap fewer particles in the same time period, and potentially make more noise and use more energy in the process. 

Some are great all-rounders, while others are better at tackling one type of pollutant than another.

Read on to find out whether an air purifier is right for you, the types available and how much you should expect to pay. 

Already know what you want? Check all our air purifier reviews to find one that will do a great job 

Best Buy air purifiers for 2024

We've put the most popular models on the market through our lab tests.

Log in or join Which? to access all our Best Buys and air purifier reviews. We've tested over 40 air purifiers from brands including AEG, Dyson, Blueair and Philips, but only the very best become a Best Buy.

The pollutants we test for

We test air purifiers with small, medium and large particles, as these are representative of a range of common household allergens. 

We can't specifically test using traffic pollution particles, a concerning pollutant you may be keen to get rid of, but an air purifier that performs well in our small particle tests is likely to also do a good job of trapping harmful PM2.5 particles found in traffic pollution, which are a similar size 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. If you're worried about pollution from a busy road, look for one that also has a carbon filter, as these are designed to trap gases. We also test to see how effectively an air purifier can filter gases.

Find out more in how we test air purifiers.

Do I need an air purifier?

An air purifier isn't the first line of defence against indoor air pollution. Ultimately, generating less indoor pollution means you'll be breathing cleaner air. 

If so, start by eliminating the sources of air pollution in your home and ventilate.

For example:

• Minimise your use of chemical products, especially sprays and aerosols
• Keep humidity under control, to avoid biological contaminants such as mildew and mould. A Best Buy dehumidifier will help.
• Open windows, particularly after any activities that cause air pollution, such as cleaning, dusting or decorating
• However, 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.

If it's not possible to increase ventilation because your outdoor air quality is poor or you suffer from hay fever and open windows introduce pollen, then an air purifier could be a good investment. 

Remember that you'll need to close the doors and windows of the room with the air purifier so it works effectively.

Your air purifier won't be able to clean the air throughout your whole property, as it will come with a maximum room size.  

Our tests show that using one 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 huge. 

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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 on the market, but if you’re buying one we haven’t reviewed, choose one with a HEPA filter. 

A HEPA filter doesn’t guarantee that an air purifier will be good as there are other aspects that might make it a bad machine. At least one 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, so 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 money on replacements. Always follow the manufacturer instructions, though. 

If you do vacuum your filter, go gently as it 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.

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 its estimation), in the form of a coloured light on the display. If you've got a smart air purifier (one that's internet connected), you may also get more detailed information sent to your smartphone app. 

Suffer from a pollen or dust allergy? Find out which are best at removing these types of particles from the air in all of our air purifier reviews.

Air purifier timers

Most air purifiers come with a timer, which 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, quieter speed in the evening and during the 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, 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.

Smart air purifiers

Smart air purifiers tend to be more expensive, but 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. 

Those we've tested include the Blueair Classic 605 and  Blueair Classic 405.

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

Which smart air purifier brands offer the best software and security support?

Software and security support are important considerations when buying any smart product, dictating how long the brand continues updating the device with features and security patches, to guard against emerging threats.

We reached out to the biggest brands to find out more about support policies, and some are better than others.

• AEG offers a decent policy of five years from end of sale. 
• ElectriQ offers a minimum of five years of support from launch.
• Beurer and Ikea both told us they will support their smart air purifiers for five years.
• Duux said it will support its air purifiers for a minimum of five years. 
• BlueAir did not have a general policy but appears to support its products for four years.
• Meaco offers at least three years of support from launch. 
• Dyson did not share a general policy but appears to offer up to seven years. 
• Hoover only offer two years of support from purchase, as does Philips. 

While you may not be at immediate risk if you're using a device that's unsupported, it's obviously desirable to buy and use a device that you know will receive update support for a decent period of time. For more information, read our guide to smart devices and security.

How much do air purifiers cost?

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, you’ll need to spend at least £200. Most of our Best Buys cost between £200 and £400. 

Spending this much doesn’t guarantee you’ll avoid the duds, though. One of the models we've made a Don't Buy is sold for over £400, which is at the top end of the market, so check our reviews before getting one.

How much does an air purifier cost to run?

Obviously, the running costs 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, 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.

Where to buy an air purifier

Popular online retailers include:

• Amazon has plenty of models to choose from, including cheaper air purifiers from Levoit, but pay attention to the seller's customer score.
• Argos offers a selection of air purifiers, the majority of which are by Blueair and Dyson. Prices start at around £60 and rise beyond £500 for some Dyson models. If you buy online before 5pm, Argos delivers by 10pm the same day for £5.95, subject to availability.
• Currys stocks them from a vast selection of brands. Prices start at around £45 for small entry-level models from Beldray and Russell Hobbs.
• John Lewis sells air purifiers from AEG, Blueair, Dyson, Meaco, Philips and Shark.

To see which retailers are rated highly by Which? members, see the best and worst shops.

Do air purifier filters need replacing?  

Yes. All filters have a lifespan, the length of which depends on how often you use yours, how often you clean the filter and how dirty the air in your home is. Manufacturers generally recommend that you change it 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 the 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 them, the filter will eventually clog up and the model will no longer work. Keep this in mind if you buy a second-hand model, as filters may be tricky to get hold of for some older models. 

We check the availability of filters for our Best Buys. If any have long-term 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 yours has reached the end of its lifespan, it's important to dispose of it responsibly and, in most cases, you should be able to recycle it. Look for the crossed out wheelie bin symbol as this indicates that it can be. 

Before you do, 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 will 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 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 electrical items.

How quiet are air purifiers?

All models make a bit of noise in use, but some are far louder than others, particularly on the highest setting. The quietest do a very good job both on the lowest and highest setting. 

Some 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, you can use our reviews to find the ones that are genuinely quiet on their lowest or night setting. The difference between the 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 one that's loud at night or in 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 will be much cleaner at the point you try to sleep.

Unless you can try out an air purifier out before you buy, the only way you can tell if it's likely to disturb you or not is with our air purifier 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 usually need to worry about air purifiers that use a HEPA filter alone to clean the air. However, ionizing models, or those that use UV lights, could give off ozone because of the electric charge. If you can, look for one that states that it doesn't create ozone. And you should avoid any that are described as 'ozone generators'.

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