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6 air purifier myths busted

CHOICE air purifier expert Chris Barnes filters facts from fiction.

air purifier in a room with a woman sitting on couch
Last updated: 16 January 2024


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

An air purifier can be a great addition to your home, improving air quality, reducing irritation and helping those prone to asthma and allergies. However, it's important to remember that you can do a lot to reduce indoor air pollution simply by regularly vacuuming, mopping and airing your home.

If you do decide you need an air purifier, exaggerated marketing claims can make it difficult to tell fact from fiction. To help you make sense of it, CHOICE air purifier expert Chris Barnes set us straight on some of the most common air purifier myths.

1. An air purifier means you don't need to clean

If you think that plugging in an air purifier means you can get rid of the dusters, vacuum cleaner and mop then you are going to be disappointed. 

While a good air purifier will help remove dust from the air, it can't do anything about the stuff that settles on surfaces around the home. That means you won't be able to give up on your cleaning routine quite yet. 

"Air purifiers are good but they can't get everything out," says Chris. 

"Dust on the floor or furniture still needs to be cleaned up, so dusting, vacuuming and mopping remain necessary chores," he explains.

dusting tables with cloth

Air purifiers can't remove stuff that has already settled on surfaces, so you'll still need to clean.

2. An air purifier can kill all the germs and viruses in your home

An air purifier won't magically stop viruses from spreading in your home but it can help, as long as it's a model with the features you need. 

"A HEPA filter is an incredibly dense and complicated weave of fibres. When viruses or bacteria bump into that filter they will stay there and die," Chris says. 

While the CHOICE lab doesn't test with viruses or bacteria, we do test with dust, smoke and volatile organic compounds. 

A HEPA filter is an incredibly dense and complicated weave of fibres. When viruses or bacteria bump into that filter they will stay there and die

CHOICE expert Chris Barnes

"Any model that is good at removing fine dust and smoke will likely also be good at trapping germs that are in the air," explains Chris.

Using a special test room, we add the pollutant to the air and see how long it takes to come out of the air by itself. Then we do the same thing with the air purifier running and measure it again.

"The best air purifiers remove pollutants very quickly," Chris says, "but with the worst that we've tested it's like you haven't bothered putting one in at all."

3. An air purifier replaces the need for ventilation

An efficient air purifier is great but it's no replacement for good ventilation.

To prevent the build-up of carbon dioxide, odours, moisture and other pollutants, the air in a room should ideally be replaced by fresh air several times an hour. 

"The easiest way to do that is by opening doors and windows and allowing a breeze to do the work," says Chris. "If that's not possible, an air purifier can help, but it's unlikely to achieve the same level of air change in the long term as good ventilation."

opening windows is vital for good airflow

Even with an air purifier, good ventilation is still important.

4. All air purifiers filter out dangerous chemicals

When we test air purifiers we measure their ability to remove volatile organic compounds (VOC), the kinds of chemicals that are typically released into the air from paint, furniture, aerosol sprays, cleaning products and so on. 

"These sorts of chemicals can cause breathing and skin irritation, headaches and worse," says Chris. "While some air purifiers are specifically designed to remove such chemicals, most are not very effective and several are pretty useless at this particular task."

If you're looking for a way to clear these sorts of indoor pollutants, good ventilation (i.e. opening a window and turning a fan on) is likely to be much more helpful than an air purifier. 

5. All air purifiers can be used in rooms of any size

An air purifier that works in a small bedroom won't necessarily do an efficient job in a large open-plan living room. When choosing the right model for your requirements, you'll need to ensure the air purifier you buy can circulate the full volume of air in your room, otherwise, it simply won't perform the job you've bought it for.

Most air purifiers come with a claimed room size, which can be anything from 20m2 (about the size of a medium to large bedroom or small lounge) all the way up to more than 200m2 which is only slightly smaller than the total size of the average Australian freestanding house. You should take note of that figure when you are purchasing. 

You'll need to ensure the air purifier you buy can circulate the full volume of air in your room

"It may be worth getting a model that's rated for a larger room than you plan to use it in," says Chris. "That way, 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 which is especially important if you're using it while trying to sleep."

6. Air purifiers are a one-off cost

The air purifiers we recommend in our tests range in price from $599 up to $1695, and as is often the case, price is not a reliable indicator of performance. Whatever you pay for your air purifier, it's worth bearing in mind that the cost doesn't end there.

If your air purifier uses a pre-filter or carbon filter, most of these can be washed, dried and reused but HEPA filters will need to be replaced periodically. You can help your HEPA filter last longer by gently brushing or vacuuming it regularly. You'll still need to replace it, but you won't have to do it as often, which will help save you money.

"Filters are a key ongoing expense for these sorts of products," says Chris.

"They will need replacing, though how often you need to do that will depend on how often you use the purifier and the level of pollution in your home," he says.

"You could end up spending hundreds of dollars a year just on filters, so it's important to find out what the replacement costs are for the filters you'll need for the model you're looking at."

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.

Stock images: Getty, unless otherwise stated.