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Do air purifiers really work?

Our expert take on what they can and can't do and whether they are worth your money.

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Last updated: 21 September 2021
Fact-checked

Fact-checked

Checked for accuracy by our qualified fact-checkers and verifiers. Find out more about fact-checking at CHOICE.

Need to know

  • Air purifiers are growing in popularity and there are a huge range of brands and types available
  • CHOICE rates different models based on things such as how well they remove smoke, dust and other irritants from the air, and their ease of use
  • Air purifiers can help to clear the air of viruses such as COVID-19, but they're not a perfect solution

As we learn to live with a heightened awareness of airborne viruses such as COVID-19, and head into another Australian bushfire season, retailers are seeing a growing interest in air purifiers. Not to mention that spring has sprung and the associated levels of pollen and cases of hayfever are on the rise again!

Air purifiers are billed as an easy way to improve the air quality in our homes, school or workplaces, and there's a huge variety of brands, sizes and types available at a wide range of prices. Some boast sleek designs and impressive-sounding features, from virus-zapping UV lights to activated carbon filters and Wi-Fi connectivity. Plus, there's a whole host of acronyms you've probably never heard of – HEPA, CADR, VOC – what? 

In a new take on futuristic fashion, there's even wearable air purifiers you hang around your neck like a necklace (spoiler: studies indicate that most of these are not very effective, and they could be largely useless in the open air; you'd be better off just wearing a mask). 

So, can standard air purifiers actually benefit your health – improving air quality to reduce bacteria and the risk of viruses, for example, or lessen the effects of bushfire smoke and other irritants such as dust, pollen and chemicals – or are they just another useless fad?

CHOICE household expert Chris Barnes says, not all air purifiers are created equally and they do have their limitations. Whether an air purifier is worth buying and how much you should spend depends on things such as what you'd like to use it for and the effectiveness of the product you buy.

"We have reviewed a range of air purifiers from different brands, ranging in price from $79 to over $1500," says Chris. "We measure the Clean Air Delivery Rate (CADR) of each air purifier to assess how well it clears particles of dust, smoke and other volatile organic compounds (VOC) from the air, and use that information to give each model a score based on its performance and ease of use. 

We are seeing some disappointing products in our labs, some which barely clear anything from the air

CHOICE Expert, Chris Barnes

"The performance of different brands and types of air purifiers definitely varies and we are seeing some disappointing products in our labs, some which barely clear anything from the air," he says. "How well a model will perform in your home can be affected by things such as its relative size to the size and shape of the room you're using it in, as well as how many, and which, pollutants are in your air." 

Can an air purifier remove bushfire smoke and other irritants from the air?

Smoke from back-burning or actual bushfires is a reality of living in Australia and can be very irritating or even damaging for asthma sufferers or people with other health conditions. 

"Yes, a good air purifier can help clear the air of smoke from bushfires or tobacco, and odours, but you should look for a product with a HEPA filter, which is a filter that traps very small particles," says Chris. "It's one of the most important features of an air purifier – not all purifiers on the market have this, so make sure you check the product specifications."

Look for a product with a HEPA filter, which traps very small particles ... It's one of the most important features of an air purifier

CHOICE household expert, Chris Barnes

The HEPA filter may be used in conjunction with another type of filter such as carbon, charcoal, ionisation or UV filter, and all have different key uses and effectiveness. For more on different types of filters to look out for, read our air purifier buying guide

Air purifiers can also help remove common household allergens, such as dust, pollen and mould, that can trigger hay fever, asthma and other respiratory conditions. In our expert reviews, we give individual performance scores for how well each model removes smoke, dust and volatile organic compounds (VOCs) from the air, so you can check each model's performance against your specific concerns before you buy.

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A good air purifier can help clear the air of smoke from bushfires or tobacco, and odours, but you should look for a product with a HEPA filter.

Will an air purifier kill coronavirus and other bacteria? 

While we'd all love a magic COVID-busting appliance in our homes, air purifiers aren't the perfect solution. But, they can be useful. 

"An air purifier with a HEPA filter can be surprisingly good at trapping viruses and bacteria out of the air," says Chris. "The issue is that it can only process what's in the air that it happened to suck in at the time, so wouldn't necessarily process all the air in your home to trap and kill a virus that may be present.

"But, in addition to following health advice such as regularly washing your hands, an air purifier might be worth considering as an extra protection against airborne viruses if you have people coming and going in your house, such as kids going to school or essential workers, or if it's hard to keep your home freshly aired."

We don't test the ability of air purifiers to kill viruses in our labs, but you can read more: Do air purifiers trap viruses and other germs? 

What size/capacity air purifier will work best in my home?

Size really matters here! When choosing an air purifier, our experts recommend you look especially closely at the advertised Clean Air Delivery Rate (CADR) and consider the size of the room you will be using it in. Most models will advertise what capacity room they are suited for. You basically want to ensure that the air purifier works hard enough – or has a CADR that's high enough – that it can circulate the full volume of air in your room to clean it thoroughly, otherwise it won't be doing the job you bought it for. 

Generally, the higher the CADR the better, but keep in mind this standard is tested using very specific settings i.e. with the purifier unit placed in the centre of the room and set to its highest speed setting, and it only relates to the removal of three pollutants – dust, tobacco smoke and pollen. 

It may be worth getting a model that's rated for a slightly larger room than you plan to use it in

CHOICE household expert, Chris Barnes

Chris suggests: "It may be worth getting a model that's rated for a slightly larger room than you plan to use it in. That can mean the purifier will clear the room's air faster on its highest setting, but still comfortably keep the air clear on its lowest and quietest speed (good for when you're trying to sleep)."

Find out more about CADR and the Dyson-specific test method known as POLAR, in our air purifier buying guide.

Ongoing costs to consider

There's nothing worse than being hit with unexpected costs, so if you're considering whether you should buy an air purifier, ensure you take into account the cost of replacement filters, which can add up quickly.

Costs vary between brands and models, and replacement filters for the models we've tested can range from about $55 to $89 each, which could add up to well over $100 per year depending on how often you run your purifier and at what setting. Check our air purifier reviews for filter prices and estimated annual costs on models we've tested.

We care about accuracy. See something that's not quite right in this article? Let us know or read more about fact-checking at CHOICE