How to clean your air purifier—and how often you should clean it

Learn how to clean your air purifier with our easy guide.

The best air purifiers will keep the air in your home clean, fresh and healthy - but it's important to make sure that the air purifier itself is clean too. It can't filter the air if it is clogged with dirt. 

Air purifiers are rather like vacuum cleaners, although thankfully they’re an awful lot quieter. Their fan pulls in air and passes it through a filter that traps large particles such as dust, allergens and irritants. The result? You can breathe more easily. Unfortunately, there’s another way in which they resemble vacuums: They fill up with dust and dirt and lose their efficiency. Those trapped particles eventually clog up the filter, making it a lot less effective. 

The good news is that it’s quick and easy to restore it to peak performance and improve the air quality of your home. 

How to clean an air purifier

What parts of your air purifier do you need to clean?

Get to grips with how an air purifier works and you will see that there are three bits you should pay particular attention to when it comes to cleaning: 

• The air inlet
• The air outlet 
• The air filter

If the first two are a bit fuzzy, a soft brush around the vent(s) should do the trick, but cleaning or replacing the air filter will require you to open up the air purifier and take the filter out. 

It’s very likely that your air purifier has a HEPA (high-efficiency particulate air) filter, because all the best models do. HEPA filters are made from various materials, but they all do the same job, using paper-like sheets of very finely spaced fibres to trap tiny particles from the air that’s passed through them.

Even the best air purifiers for dust will collect dirt in them - so removing the filter can be a bit dusty sometimes. This means that it’s wise to do it in a well-ventilated space and have your vacuum cleaner handy. Remember, you should also always switch off and unplug electrical devices before opening them up.

How often should I clean my air purifier?

This will differ from home to home – a purifier that’s running all day, every day, will need to be cleaned more frequently than one that’s only used from time to time –but manufacturers usually recommend changing or cleaning the filter every three to six months to enjoy all the benefits of air purifiers. But if you have one of the best air purifiers for allergies, the recommended frequency is one to two months. Some filters are made to last longer, so for example the filter in a Dyson Pure Cool device is good for a year.

Should I clean the filter or replace it?

That depends on what kind of air purifier you have. Some filters are supposed to be replaced, rather than cleaned; some can be cleaned a few times but should be replaced at specified intervals; and some can be cleaned and put back for as long as you have your purifier. 

If you didn’t keep the manual for your air purifier, search for it online – you need to know whether the filter in your air purifier is washable, because washing non-washable filters can damage them. There may be special washing instructions, too – for example, with some filters you might find that only part of it is washable. 

HEPA filters can be very delicate things, so it’s really important to play it safe here. If you can’t find out whether your filter is washable, assume that it isn’t. 

How to clean a washable HEPA filter

Remove the filter from your air purifier – check the manual for instructions on how to do this, or look online if you can’t find it, and see if there are any special instructions.

If it’s OK to wash the whole thing, rinse it gently under cold water until there’s nothing but water coming out. Don’t use any cleaning products on it, not even a squirt of washing-up liquid. Leave the filter to dry and don’t put it back if it’s still damp – you don’t want to end up with mould growing in your air filter.

How to clean a non-washable HEPA filter

Remove the filter from your air purifier – check the manual for instructions on how to do this, or look online if you can’t find it – and very gently clean it with a soft brush or with the brush attachment of your vacuum cleaner, provided your vacuum cleaner has its own HEPA filter. If it doesn’t, you’re not getting rid of the dust and other irritants – you’re just sucking them out of the filter and putting them back into the air again.