Up until 2019, air purifiers were a relatively niche appliance in Australia. “Hardly anyone had an air purifier in their house,” says Chris Barnes of consumer advocacy group Choice. What happened next need not be revisited, but, Barnes says: “They’ve become a lot more commonplace and people are a lot more conscious of indoor air quality.”
With the arrival of El Niño threatening another smoke-choked summer, many Australians will be dusting off their air purifiers for the first time in years, or contemplating making a purchase.
First-time buyers are in a better position than ever, Barnes says. “You can go into a major appliance retailer or look online and there’s a lot of product out there.”
“But at the same time, don’t leave it to a smoky day and then run off to Harvey Norman.”
Meanwhile, those who bought what they could get their hands on, back when air purifiers were harder to find, face a potentially more complicated challenge: maintenance.
Much like vacuum cleaners, washing machines, and basically all cleaning appliances, air purifiers can get absolutely filthy. On top of this, their filters are typically “consumables” that require regular replacement.
For this reason, Barnes recommends anyone pulling their air purifier out of storage ensures filters are still available for the model they own. “If you bought something like a no-name brand … it might be that you’ve got a filter that it’s going to be hard to find now.”
He suggests planning ahead to beat potential stock shortages. “If you’ve already got [an air purifier], and maybe you’re not sure how long the filter’s going to last, make sure you’ve got a spare filter on hand.”
Dusting the machine off
If an air purifier has been sitting in storage, the biggest issue is likely to be dust accumulation, which can lead to mould growth. James Shale, an engineer at Dyson, suggests opening the machine up and checking the filter for mould before you turn it on.
Barnes adds you should “make sure dust hasn’t clogged up the air intakes or anything like that – which is a bit ironic given the job of the thing is to actually remove dust out of the air”. He also suggests basic safety precautions like checking for damage to the power cord, “as you would with any appliance”.
If there’s no mould, no dust and the machine doesn’t look damaged, it should be good to go.
However, Shale says that air purifiers which include a heating element may start to smell when turned on after a long period of disuse. This smell “is the dust actually burning off the heating elements. So there’s nothing unhygienic or unhealthy about it, it’s actually a good thing”. Because of the smell, he recommends running the device for up to 15 minutes in a place where odours won’t bother you, before using it somewhere they will.
Maintenance while in use
While most air purifiers work in basically the same way – “they’re really just a fan and a filter,” Barnes says – their cleaning requirements vary significantly.
While some just need a dust-down, other manufacturers recommend regular disassembling and cleaning them regularly.
A representative of Winix, one of the first widely available air purifier lines in Australia, says with their products: “The important thing is to clean the pre filter once a month with a light vacuum; or gently rinse and replace when dry … The inside cavity should also be wiped out and vacuumed cleaned at the same time.”
I ignored these directions for about six months with my own Winix air purifier; while also running it constantly in my bedroom. When I opened the front of the machine, I was greeted with a thick, grey carpet of dust.
I may be a sloth, but I am not the only sloth. At Dyson repair centres, “often we see customers abuse their machine,” Shale says. He typically uses an air compressor to remedy situations like mine. “If we think there’s been a lot of dust accumulation on the motor we blow it out”.
As I do not have an air compressor, it takes a vacuum and an aggressive, half-hour brush-down to remove all the dust from the machine’s nooks and crannies.
When to change the filter
Most air purifiers sold in Australia use either a HEPA filter, or a combination of HEPA and carbon filters. While Shale and Barnes both say that running an air purifier past its filter life likely won’t make your home air quality worse, it will not make it any better, either.
Most air purifiers have a notification system for when their filters are full, though this may be based only on a timer. “You’ve got to kind of assume that the appliance is telling you the truth,” Barnes says. When you ignore filter replacement warnings, “the risk is that you don’t know actually if the filter’s still doing its job. You’re sort of in the lap of the gods there”.
Shale likens HEPA filters to a sheet that can be shaken out before it needs changing. “We don’t recommend this, this is not a Dyson policy, but you can actually vacuum them, put them back in and overrun them,” he says. “Basically how all HEPA filters work is they take cloth fibre material, fold it over as many times as you can, and that gives you a massive surface area to capture solid particulate matter,” Shale says. “So think dust mites, think pollen, think bacteria, stuff like that. Anything that has a physical presence.”
Carbon filters are designed to absorb gaseous air contaminants like NO2 (which comes from car exhaust fumes) and volatile organic compounds (VOCs). “So when you can smell stuff and it has an odour, that’s going to be volatile organic compounds,” Shale says. These are more like a bin bag. “When the bin bag is full and it gets to the point where the bin bag’s starting to be stretched, there is nothing else that you can do.”
Also like a bin bag, “when it’s completely saturated, it’ll start to smell,” he says. “The smell is a sweet, sour odour, like gone-off milk. [That] is the sign that your gaseous core filter is completely gone.”
Buying tips
Barnes says air purifiers, by and large, do improve your home’s air quality. “There are certainly a few that we’ve found that don’t do the job very well, but for the most part, they all have some reasonable effects.”
“They are really good when smoke’s got into the house, whether because you’ve burnt the cooking or because there’s bushfire smoke in the air.”
At Choice, air purifiers are ranked against each other based on their ability to rid the air of dust, smoke and VOCs – along with their energy efficiency, quietness and ease of use.
However, the machine’s initial price and its efficacy aren’t the only factors consumers should consider. “Filter replacement costs can be quite pricey, and it’s definitely something to have a look at,” Barnes says.
Filters “wear out as you use them,” Barnes says, so you will get a longer life from them if the machine is not in regular use. However, a cheap model can quickly become a bad deal if its replacement filters are expensive and you use it all the time. “You can end up paying hundreds of dollars a year on filters.”
Maintenance is also worth factoring in. If you’re unlikely to remember to clean a pre-filter regularly, and you’re considering a few models, read the manuals first – and pick a purifier that doesn’t need this kind of upkeep.
Finally, Barnes cautions that less dust in the air will not relieve you of other household chores. “Unfortunately, from experience, they don’t stop the need to keep vacuuming and dusting.”
