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How to clean an air purifier

From cleaning and replacing the filters to checking the sensors, here are our best tips for maintaining your air purifier.

changing air purifier filter
Last updated: 15 November 2023


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

Need to know

  • To keep your air purifier performing well, it's essential to regularly replace the filters and keep your unit clean
  • You can wash, dry and reuse most pre-filters and carbon filters, but you'll need to buy a replacement HEPA filter from time to time, and these costs can add up
  • CHOICE industry experts comprehensively lab test leading air purifier brands like Dyson, Philips and Winix to help you find the best performers on the market, and CHOICE members have exclusive access to our reviews of 39 models

If you've invested in an air purifier to improve the air quality in your home or work space, it's crucial you keep the unit clean and well-maintained to make sure it continues performing. This includes cleaning the filters and replacing them regularly. 

The filters in an air purifier play a vital role in capturing and removing airborne contaminants like dust, pollen, pet dander and smoke from the air, and over time the filters can become clogged and less effective.

A little maintenance here and there will reduce the strain on the air purifier's motor, keeping it working efficiently and helping you breathe a little easier. 

Can you clean an air purifier filter?

Most air purifiers have a pre-filter, HEPA filter, and sometimes an activated carbon filter. You can wash, dry and reuse most pre-filters and carbon filters, but you'll need to buy a replacement HEPA filter from time to time. This is because HEPA filters cannot be cleaned, as cleaning them tends to destroy their structure that keeps them filtering well.

If you give the HEPA filter a gentle brush or vacuum regularly, though, you won't have to replace it as often, which will save you money. 

Some air purifiers have separate filters, so you can clean them individually and  buy each one as it needs replacing, but others have an all-in-one filter cartridge which can mean you'll need to replace the entire filter each time.

How long do air purifier filters last?

When you buy an air purifier, the manufacturer will likely include a recommendation for how often you should replace the filters, rather than detailed information about how long the filters will actually last. This advice is often given in hours or months, and we find that the recommendations vary wildly. 

How long your filters will last depends on your environment (such as the air quality in your area), how often you use the air purifier and whether you do anything to maintain your air purifier.

Of the 60 air purifiers we've tested, only eight will alert you as to when they need replacement

While we haven't conducted a lifespan test on air purifier filters, we suspect that you can probably get away with keeping your filters in for longer than the length of time recommended by the manufacturer. Over time, however, you can expect a loss of filtering efficiency. 

If the filters are really getting clogged by extreme pollutants, it'll be harder for the unit to operate, pulling contaminants into the filter and keeping them there, which will strain the motor and ultimately reduce the life of your air purifier.

How often should you change air purifier filters?

Firstly, refer to the user manual to find out how often the manufacturer recommends changing the air purifier filters to maintain optimal performance. 

During our expert testing, we've looked at manuals for over 60 purifiers and we typically see advice given to clean pre-filters every 2–3 weeks, and advice to replace HEPA and/or carbon filters anywhere from every three months to every two years. If you're not using your air purifier very often, your filters will last longer.

  • Clean pre-filters every 2 weeks to 3 months.
  • Clean or replace carbon filters every 3 months to 2 years.
  • Replace HEPA filters anywhere from every 3 months to 2 years.

Some air purifiers will let you remove and soak a carbon filter or pre-filter to clean it and dry it off before reinstalling. HEPA filters require complete replacement, and costs for these replacement filters start at $18 and go up to $280 depending on the manufacturer (for the models we've looked at). Some models will even refuse to operate until the filter is replaced.

Investing in high-quality replacement filters is a smart choice, as they ensure your air purifier operates at its best, providing clean and healthy air for your home or office. 

How much do replacement filters cost?

We've tested air purifiers that cost between $99 and $1730, and even if you opted for a cheaper air purifier to begin with, the ongoing cost of replacement filters can add up to hundreds of dollars over the lifetime of the appliance. 

The cost of replacing air purifier filters varies depending on the manufacturer, so we've detailed the range of filter costs per year for each major brand for which we've reviewed multiple models.

Replacing your air purifier filters
Brand Price of filters (per year)
 Beurer $180–200
 Breville $60–200
 Coway $140–269
 Dyson $99
 Ikea $70–90
 InovaAir $132–224
 Ionmax $70–276
 Kogan $172– 280
 Philips $40–130
 Samsung $119–298
 Sharp $35–75
 TruSens $54–128
 Winix $149–169

These figures are helpful to give you an idea of what you're up for on a yearly basis in terms of filter running costs, but check our test results for the most important element – how well the purifier removes contaminants from the air.

How to dispose of air purifier filters

Some air purifiers have recommendations on how to dispose of their various types of filters. Some claim to be recyclable, while others are likely destined for landfill. 

As a first step, check your manual for how to dispose of any filters you're replacing in your air purifier. You can also contact your local council or recycling service to investigate options for recycling old filters. 

How to clean an air purifier pre-filter

While not the main filter, pre-filters trap larger particles, and cleaning or replacing them helps maintain the unit's efficiency. 

Some of the pre-filters are changed when you replace the HEPA filter, but some require cleaning in between changes. You may need to be careful with fabric pre-filters so you don't damage them. Check your manual for tips on how best to clean yours.

If your pre-filter is affixed, you may need to vacuum the filter with the brush tool of your vacuum as gently as possible so it doesn't damage the pre-filter mesh. 

Where the pre-filter is not fixed to the purifier, you can take it out to clean. Check the manufacturer's instructions but generally you can follow these steps:

  1. Make sure the space you're in is well ventilated. Switch off the air purifier and unplug it from the wall outlet. Remove the pre-filter.
  2. Rinse the filter with warm water until the water runs clear. If the pre-filter is very dirty, use a soft brush to brush away the dust.
  3. Gently wring out excess water.
  4. Leave the pre-filter to thoroughly air dry before replacing.

How to clean a carbon filter

Where carbon filters are able to be cleaned, generally they just need to be placed in some water and left to sit for some time before retrieving them, drying them and returning them to the purifier.

woman and dog lying on the lounge near an air purifier

Keep the area around your air purifier clear so that there's good ventilation and airflow.

Tips for maintaining your air purifier

As well as regularly cleaning and replacing your filters, there are a few simple things you can do to make sure your air purifier continues to function efficiently and keeps the air in your living space fresh and clean. 

  1. Wipe down the exterior regularly with a damp cloth. This will not only keep the air purifier looking clean (it's probably a prominent feature in your living space, after all) but can prevent any excess dust finding its way into the appliance.
  2. Keep an eye out for leaks or cracks in the exterior of your air purifier that can affect its performance.
  3. Keep the area around your air purifier clear so that there's good ventilation and airflow, ensuring in particular that vents and fans are unobstructed. Some of them come off for ease of cleaning (compared to those that are permanently affixed to an air purifier) and some have fabric-covered grilles you can vacuum.
  4. Be aware of unusual noises. While different air purifiers create different levels of noise during operation (during our expert air purifier testing we measure how quiet and loud they are), and some noise is to be expected,  unusual noises could be indicative of a problem you need to address.
  5. Take note of indicators or error codes. Some air purifiers will alert you when it's time to replace or clean a filter, or if certain features or sensors aren't working. Take note of the alerts and consult your manual to troubleshoot. 
  6. Monitor performance. If you notice that the air purifier isn't working as well as it usually does, it may be a sign that it's time to clean or replace filters, or that there's a more serious issue that needs to be addressed. 

How to clean the air purifier sensors

Many air purifiers are equipped with sensors that monitor the air quality in your environment, allowing them to automatically adjust their settings to meet your specific needs. 

Over time, these sensors can accumulate dust, dirt, or other particles, which can interfere with their accuracy and performance, so it's important to keep them clean in order to prolong the lifespan of your air purifier and make sure it does its job.

Check your air purifier's manual for specific instructions, but here are some general steps to follow: 

  1. Turn off the unit and unplug it for safety. Gently remove the sensor cover or casing and access the sensor itself.
  2. Use a soft, lint-free cloth to carefully wipe away any accumulated debris. Avoid using harsh chemicals or abrasive materials that could damage the sensor.
  3. After cleaning, reassemble the sensor components and plug in the air purifier. 
  4. It's a good idea to allow the unit some time to recalibrate and ensure the sensors are functioning correctly. 
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Stock images: Getty, unless otherwise stated.