How often should you change an air purifier filter? Experts urge everyone to follow this timeline to protect their health and home

If you have one of these handy appliances at home, chances are you haven't given much thought to when (and even if) you need to change an air purifier filter. But it's something you need to do... and often quite regularly.

The best air purifiers will trap dust, allergens and bacteria and keep the air in your home clean and healthy, but let's face it, regularly cleaning your air purifier probably isn't on the top of your to-do-list! However, like most household appliances, air purifiers require a little TLC to keep them running effectively for as long as possible.

Several factors can cause an air purifier to stop working - a faulty filter being up there. At some point, the majority of air purifier filters will need replacing in order for them to keep working properly (yep, it's one of the things I wish I knew before buying an air purifier). That's why I asked air quality experts how often you should actually change an air purifier filter.

How often should you change an air purifier filter?

Whilst there's no hard and fast rule when it comes to how often you should change an air purifier filter, as a general guide HEPA filters - which are the most common type - should be changed every 6-12 months. Carbon filters however, need replacing more often, every 3-6 months.

'To keep your machine in top condition, you should replace your air purifier’s HEPA filter once every 6-12 months, depending on frequency of use,' advises Noel Fok, CEO and co-founder of EcoAir.

Dyson engineer, Shawn Navarednam, agrees, 'It is recommended that air purifier filters are changed every 12 months following regular use, though it depends on pollutant levels in your home, where you live and how often you’re using the machine,' he says.

However, many air purifier brands are now designing models that require minimal replacements - if any at all. The filter of the Shark NeverChange5 Air Purifier will last an incredible five years before you need to change it, and the Vitesy Eteria Portable Air Purifier filter doesn't need replacing at all.

But as they're a relatively new addition to the air purifier world, it still remains to be seen whether this is truly the case. That's why it's a good idea to also good to know the signs to look out for that indicate it's time for an air purifier filter replacement.

The good news is they're all pretty easy to spot...

The 5 signs it's time to change an air purifier filter

1. Allergy or asthma symptoms worsen

Air purifiers can help with allergies, as they capture airborne particles, dust and pollutants in your home, reducing their presence in the air. Over time, the filter can become clogged and, as a result, will be unable to trap these allergens.

So, if you have asthma or suffer from seasonal allergies, such as hay fever, and your symptoms start to worsen, this is one of the biggest alarm bells that indicate you need an air purifier filter replacement.

'You may need to change your air filter more frequently if you experience allergy or asthma symptoms, or if you have pets,' Shawn advises.

2. The airflow isn't as powerful

Another obvious tell-tale sign that you need an air purifier replacement is if you notice the airflow in the room isn't as powerful.

'Reduced airflow could indicate that the filter is clogged or that its performance has been affected,' Noel says.

'HEPA filters, used in many air purifiers, are made up of a very fine mesh. Wear and tear over time will create tiny holes, inevitably affecting the number of particles captured,' explains Noel.

3. It starts to smell

Certain air purifiers are designed to remove unpleasant odours (is there anything this nifty gadget can't do?!). If you're asking yourself 'why does my air purifier smell?' then it could be a sign you need an air purifier filter replacement.

'Over time, a clogged or saturated filter can lead to lingering odours because activated carbon loses its ability to absorb smells,' says Lars Dunberger, head of technology at Blueair.

'In some cases trapped organic particles may also promote bacteria or mould growth unless the filter is equipped with germ busting technologies,' Lars explains.

4. The room looks dustier than usual

An air purifier is designed to trap dust in the air, so if you start to see more dust than usual circulating and built up on surfaces - it could mean the filter in your air purifier is clogged.

'A good way to know when it’s time to replace your filter is when you notice more dust buildup than usual from your air purifier,' says Noel from EcoAir.

'Using a filter which is filled with dust won't bring dangerous components to your home. But if the filter is full, it may be difficult for the clean air to come out and it might damage the air purifier in the long run,' warns Lars.

So, increased dust is yet another red flag that you need an air purifier filter replacement.

5. It's loud or making unusual noises

Whilst you'll probably struggle to find an air purifier that doesn't make a sound, if it starts to make strange sounds or it is generally getting noisier, chances are you need an air purifier filter replacement.

'Restricted airflow forces the air purifier’s fan and motor to work harder, which can create whirring, rattling, or buzzing noises as the system strains to push air through a blocked filter,' says Lars Dunberger at Blueair.

'Replacing the filter on time prevents this issues, ensuring the purifier continues to run quietly and effectively while keeping your air fresh,' he adds.

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FAQS

What is the life expectancy of an air purifier?

Whilst we've made no secret of the fact we are big fans of this must-have appliance, air purifiers are an investment. If you're still weighing up if air purifiers are worth it, you'll no doubt want to know how long it's going to last.

When well-maintained, an air purifier should last up to ten years,' says Noel Fok, CEO and co-founder of EcoAir.

The life expectancy of an air purifier filter varies from manufacturer to manufacturer, says Hamid Salimi, residential property manager at Daikin.

'Some only last for a year whilst others last for up to 10 years. Irrespective of this you might need to change it more frequently. For example, if you use it regularly and if the air is heavily polluted, it will need to be changed more often,' advises Hamid.

'You should factor in the cost of replacing air filters when deciding on which air purifier to buy,' Hamid adds.

Can I clean my air purifier filter instead of replacing it?

This depends on the type of filter, but the majority of air purifiers use a HEPA filter, and unfortunately there's no shortcut when it comes to replacing them as they can't be cleaned.

Noel Fok from EcoAir says, 'HEPA filters in air purifiers are designed to capture tiny particles such as dust and pollen. These filters should never be washed as the water can damage the delicate material and create gaps, which would then allow airborne particles to pass through, reducing effectiveness.'

You can however clean the pre-filter, which catches larger particles to extend the life of the main filter, says Lars from Blueair.

'The pre-filter can be easily cleaned using a dust cloth or with a soft brush. For best performance, I'd recommend cleaning the pre-filter on a weekly basis,' Lars advises.

So, with all this in mind, there's no clear-cut answer as to how often you should change an air purifier filter. But it's still a necessary step if you use one of these handy appliances in your home.