How To Tell If An Air Purifier Is Working? (5 Quick Tests)

  • Author: Irene Batres
  • Date: January 2, 2023
  • Time to read: 6 min.
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We often think that if something is clean, it is working well. This is true of many things, but not so much of air purifiers.

It is quite common for most people to install an air purifier and have no idea whether it is really cleaning up the air or not.

So, the question is how to tell if an air purifier is working.

To determine if an air purifier is working properly, a physical test can be conducted on the device. This includes checking the device’s airflow and inspecting the air filters for contaminants such as dust, pollen, and mold. Dirty filters should be replaced if needed.

Most importantly, check the filter service indicator light or particle sensor. Lastly, do an Air Quality test.

In the rest of this article, you’ll learn how to do physical checks on your air purifier. This will ensure that your air-cleaning device is working properly. And above all, you’ll have a clean, healthy pollution-free home.

How To Check If An Air Purifier Is Working?

1. Check The Indicator Lights

A good way to tell if there is an issue is to check the service lights. Depending on your air purifier type, there are different lights.

Such as the Replace filter indicators, pollen mode indicator, fan speed indicator, ion mode, and air quality indicator.

The first thing, you can do is check the replacement filter indicator light. If this indicator is on, more than likely the filter is clogged up with dirt particles, pollutants, and allergens.

Because of that, it causes the air purifier’s purification system not to work.

Normally the filter life indicator has 3 different lights. Green, Yellow, and Red. Depending on your model.

  • Green indicator light- This means all is good. This light stays on most of the time
  • i>The yellow indicator light comes on shortly before the filter should be replaced
  • Red indicator light -if it is illuminated the air filter needs to be replaced.

2. Check Filters For Contaminants: Mold, Dust, Particles

Nobody likes breathing dirty air. An Air purifier is a high-efficiency particle device that removes contaminants and airborne particles in the air.

>Not to mention, it protects you from pollutants, dust, allergens, bacteria, pet dander, dust mites, and viruses and improves air quality indoors.

However, depending on the type of air purifier you have (HEPA technology, Activated charcoal technology, UV, Negative Ion, or Ozone) it’s important to check if you have dirty air filters.

This can create bad indoor air quality and can cause the air purifier not to work.

>Although, as previously mentioned all air purifiers are different. But most require you to clean or replace the pre-filter every 2-4 weeks. This will give your air purifying device the best performance and improve the indoor air quality of the room.

The pre-filter (Activated carbon) helps to stop odors, helps to capture airborne large particles like dust mites, and captures VOCs (Volatile organic compounds), and pet hair that enters the air purifier.

On the other hand, the other purifier filters need to be replaced every 6-8 months.

>These filters are, the Medium filter, BioGs true HEPA filter, Customized filter, and charcoal-based activated carbon filter. Depending on your model.

Air Filter TypeWhen To CleanWhen To Replace
Pre-FilterEvery 2-4 Weeks6-8 Months
True HEPA & Activate Carbon FilterDo Not Clean6-8 Months

With that, here are 2 simple methods to help you check and clean the air purifier’s pre-filter. Keep in mind, all fresh air devices are different. So always refer to your device’s user manual.

Method 1. The Pre-Filter Vacuum Method:

  • Turn the device power off
  • Re
    move the front panel of the device
  • Set the vacuum power setting on low and then gently run the vacuum cleaner along the pre-filter to remove particles, dust, and pollutants.

Method 2. The Pre-Filter Washing Method

  • Turn power off
  • Re
    move pre-filter
  • Fill the sink with lukewarm tap water and gently wash with water until completely clean. About 2-3 minutes
  • Use a towel to remove excess water from pre-filter
  • Dr
    y for 12-24 hours. Once completely dry place back into the air purifier

While the air purifier front panel is open. You can check the other filters to see if they need replacing.

Once the air filters are cleaned or replaced. You then can press and hold down the filter indicator button for about 5 sec.


s will reset it. And, the light will turn from Red back to green. To do this refer to your user manual.

3. Test The Airflow

If your Air purifier is on. But, you noticed that there is no air blowing out and, it has poor air circulation. Then this means that it’s definitely not working correctly.

With that being said, you should check the air intake and outlet of the device. If you notice dust by the air intake, clean the air intake and outlet it with a soft brush or cloth.


o, check the fan inside the air purifier to see if it is moving. If it is moving, but is louder than normal or is making a lot of noise.

Then the filter needs to be replaced. The fan shouldn’t be overworking.

The fan is an important part of the purifying process, it removes the pollutants from the air in the room.


the dirty air is brought in from the fan. The dust and the particulate matter is collected in the air filters. The High amounts of dirty particles can block the pores of the filter causing the air purifier device not to work.

Once the dirty air goes through the fans and comes out of the air filter the outlet air becomes clean fresh air.

4. Air Quality Performance Check

After performing all these tests and you are still unsure if your air purifier is working correctly. Then the next best thing to do is a home air quality performance check.

In fa

ct, the best test for allergies, pollen, odor, and even mold in your home, is to do a particle test. You can do this by using an air quality monitor.

If you have allergies or asthma this is a great device to have on hand. Not only will you be able to tell if your air purifier is working. But, you will also be able to know how bad the pollution is in your home.

Below, I posted the steps in which air quality works best and how to use it.

="font-size:19px">Step 1.

You’ll need an air quality monitor. A good air quality I found that works excellently is the Brand: EG Air Quality Monitor.

It is small, accurate, and allows real-time measurement of formaldehyde (HCHO), synthetic volatile organic compounds, and fine particulate dust. On top of that, it has tons of highly-rated reviews on Amazon.

font-size:19px">Step 2.

Take the Air quality monitor (Brand: EG) and test a room that your air purifier hasn’t been in. And write down the reading.

Step 3.

Take your

air purifier and bring it to the room that you just tested with the air quality monitor. Let the air purifier run for 15-30 minutes or so. Then use the air quality monitor to record a second reading.

Keep in mind the air purifier still running. If the reading is lower than the first time your air purifier is working. 

On the other hand, if the reading from the air quality monitor is the same or higher then your air purifier is not working. Contact the manufacturer.

I hope th

is article was helpful and answered the question of how to tell if an air purifier is working.

If you liked this post check out our other helpful air purifier posts.

Further Resources

If you’re looking for more air purifier resources, consider checking out our other posts on air purifiers.

irene mills author of freshairdevices


Irene Batres

is eager to help others create an indoor allergen-free home. She has years of experience testing out air purifiers, dehumidifiers, and other products designed to help with indoor air quality. Learn more about me.