How to Check Air Purifier Filters for Replacements?

Breathing in clean and hygienic air is getting increasingly challenging with every passing year, especially in metro cities. An air purifier has become a dire necessity to cope with air pollutants and ensure healthy living.

As air purifiers clean up the indoor air by removing the harmful pollutants, these are subjected to intense filtering work-load and may get clogged over time. Thus, you need to clean or replace your air-purifier filter regularly.

As you cannot see the minute air pollutants present in the circulated air inside your home or office, you can’t make out if your air purifier is functioning efficiently with naked eyes.

This article discusses a few effective ways of checking your air purifier’s HEPA filters to confirm if these filters need replacement.

Tips to Check Air Purifier’s HEPA Filters

Checking Air Purifier’s Airflow

Checking the airflow of your air purifier is the simplest way of testing the air purifier’s efficiency. You should check if your air purifier is blowing out the clean air with normal flow.

The air purifier functions by drawing in the polluted air through the fan from inside the room. It filters out the air-pollutants, including particulate matter, from the air and blows out the healthy and hygienic air.

Thus, if your purifier is not blowing out healthy air with the normal flow as it used to when it was new, it suggests that it is not functioning optimally.

Checking the Fan Inside the Air Purifier

Check if your air purifier’s fan is functioning normally.

Ideally, the fan should not make a loud sound or work hard to blow out the healthy air. If it does make an abnormal sound, then it indicates some underlying issues with an air purifier.

On the other hand, if your air purifier is silent while working, it may not be drawing enough air to improve air quality.

Thus, if the fan of your air purifier is not working properly, you may need to replace your air purifier.

Checking the Filters in Your Air Purifier

The most common reason for the less than optimal performance of your air purifier is the presence of clogged filters. Once these air filters are clogged, you may need to clean or replace them.

As most air purifiers come with more than one filter, you need to inspect all the air purifier filters regularly.

The air filters capture the air pollutants and other particulates like pollen, dust, mould, etc. Over time, these pollutants build up in the air filters and clog them. This drastically reduces the filtering efficiency of air filters.

You should periodically check the air filters to see if you need to replace them.

If you are residing in a highly polluted area, your filters are subjected to heavy-duty cleaning, and you may need to replace them more often.

Some high-end models of air purifiers feature a filter service indicator that indicates when the air filters need replacement. This indicator uses a timer for suggesting the time frame for replacing the air filters.

While inspecting your air filters, you should check for the presence of black spots or any discolouration of filters. It suggests that your air filters have become dirty. A dirty air filter gives away polluted air and needs immediate replacement.

Using an Air-Quality Monitor 

After inspecting your air purifier, it does not imply that your air purifier is blowing healthy air if you find it looking clean. Naked eyes do not detect the microscopic air-pollutants, and you need to check the air with an air-quality monitor.

An air quality monitor serves as an effective way of checking the efficiency of your air purifier. This can work with any air purifier.

With an air quality monitor, you can easily test the air quality blown by your air purifier.

First, get the baseline air quality reading while your air purifier is off. Now switch on the air purifier and close all the doors and windows. Now keep the air quality monitor near the air purifier’s vent and wait for a few hours.

Note down the reading again. If you don’t see any substantial air quality improvement, it suggests your air purifier is not performing well and needs replacement.

Also, don’t rely too much on your air purifier’s in-built air quality monitor, as it may give you inaccurate readings.


It is important to check the performance of your air purifier periodically to replace them in time. This allows you to breathe in clean and healthy air always. It gives you peace of mind by maintaining optimal hygiene in your home.

A properly working air purifier keeps you in pink of health and protects you against various air-borne diseases and allergens.


Preksha is passionate about writing articles that will inspire readers to make better choices. You will find her eating desserts for lunch, dinner and any time of the day. Also, she is the chief playlist engineer for any road trip.

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