How to Tell If an Air Purifier is Working: 5 Ways You Can Know for Sure

If you want to know how to tell if an air purifier is working properly, you are not alone. Many purifier owners are uncertain about whether their device is working normally or not. I invite you to read this detailed informational guide so you can clear your doubts. Let’s get started!

How to Tell If an Air Purifier is Working? Quick Answer

In order to know if your air purifier is working correctly or not, you can do the following to find out:

  • Check the Air Blowing Out: Evaluate the consistency of air blowing from the purifier’s outlet to determine its functionality.
  • Have a look at the Air Filters: Regularly inspect the filters for dust accumulation. The debris and dust accumulation can hinder the air purifier’s performance.
  • Assess the Operating Sound: Monitor for steady operational sounds. Also, note any unusual noises that might indicate mechanical problems.

However, that’s not all! Continue reading to learn why the purifier is having issues and what are the 5 best ways to test its performance. I also share some effective troubleshooting steps you can take to make sure your device works with complete potential. Let’s dive deeper into the details!

Read also: How Long to Run an Air Purifier for the Best Result

1. Examining Airflow and Operating Sound

The airflow and noise method is the simplest way to determine whether air purifiers are working or not. You need to see:

How to Tell if an Air Purifier is Working: 3 Signs of Faulty
  • Air Blowing: Place your hand in front of the outtake of the purifier and see if it is throwing out air. The airflow should be regular and consistent. If not, then there could be a problem.
  • Monitor Noise: Check if the air purifier is making an operation noise. If the voice on the highest settings is too meek to even hear above ambient sound (40 dbs), then something is wrong.
  • Rattling Sound: Too loud of noise should be alarming as well. Especially if you hear loud thuds, grinding, or rattling. Ideally air purifier sound is consistent vacuum cleaner-like.

2. Do the Air Purifier Filter Test

One more easy way to check if an air purifier is working optimally is to check the filters. Here are things that you need to note:

Do the Air Purifier Filter Test
  • Dirty Filter: If the Pre and HEPA filters have air pollutants like dust, hair, and debris attached to them then the air purifier is working.
  • Wear and Tear: If the air filters have worn out and aged then it is a good and bad sign at the same time. Worn out filter means your purifier was working well but in its current state most likely it is not capturing pollutants very well. You will need a filter replacement for your air purifier to work.
  • Clogged: If the airborne particles have completely blocked the filters that not even air can pass through then the air purifier is not working. Running it on is only straining it.
Pro tip: Check the product description for filter replacement intervals and if they can be washed or not. An activated carbon filter can not be washed in most cases, HEPA filter – optionally. Also if it is possible to clean the prefilter. Just make sure you take them outside so the particles are not reintroduced into the environment.

3. The Indoor Air Quality Monitor Test

If you are still confused after the airflow and filters test because the indoor air quality might not be as you expected, then you need an indoor air quality monitor.

Let me save you time. The following are my favorite products that will let you know about the surrounding atmosphere quality and whether the air purifier is working or not.

Product Name

Qingping Air Quality Monitor

Airthings 2930 Wave Plus

Temtop Air Quality Monitor

Qingping Air Quality Monitor
Airthings 2930 Wave Plus


4 Color Coded Indicators, SmartPhone that provides detailed stats, Touch Screen Display

Shows CO2, VOC, Humidity, Temp, and Pressure. Can be powered by 2 AA Batteries

Histogram Chart to track indoor Air Quality, 6 Color, and Level Indications


The app takes time to update

It has a limited radius that will display AQ status

It lacks TVOC indication


3.35"D x 2.69"W x 3.4"H

4.75"D x 4.75"W x 1.4"H

6.06" D x 1.81" W x 8.9" H


4. Visual and Digital Indicators

To keep an eye on indoor air quality, visual indicator lights, and digital displays are quite reliable. Here is how they can help:

  • Indicator Lights: Most air purifiers have sensors inside that detect airborne particles in the atmosphere and display overall air quality through color codes.
  • Data Display: Some modern air purifiers are equipped with LED screens that are able to display real-time data while the purifier is working. It can include values of PM2.5, formaldehyde, and VOC. The stats can also be shown via bar graphs. You can pinpoint how poor air quality turned into clean air.
Visual and Digital Indicators
Tip: Keep your windows closed while monitoring indoor air. This will stop the reintroduction of other various pollutants from outside. You can try reopening the windows and checking the concentration of the pollutant to understand the difference the air purifier is making.

5. Sound Level of the Air Purifiers

As I mentioned above in the Airflow Test section, operating noise can be quite a vital indication to tell if your air purifier is functioning properly. Understand that a working air cleaner will make a buzzing sound as it has a fan inside. In case it is not, then there could be a problem.

Sound Level of the Air Purifiers

Read also: Why is My Room So Dusty? 7 Important Reasons to Know

Grinding, rattling, or loud noises are also worrisome. Working purifiers will only produce steady, consistent sound.

Fixing Issues In Your Air Purifier

By now you have probably figured out if your air purifier is working efficiently or not. So how can you fix it? No need to do another search. Read below for answers.

1. Poor Air Circulation by Air Purifier

Poor air purification might be due to the following reasons:

Poor Air Circulation by Air Purifier
  • Fan not Spinning: This could be due to some blockage inside. Check if the air purifier’s vent is not obstructed. Clear them up and it should resolve that.
  • Dust Guard: The air purifier’s performance can be affected negatively if dust accumulates on the dust guard. Clean it to get the air flowing as it should.
  • Loud Noise: If the air purification is taking more time than usual and the machine is making louder noise then check the filters. It is a possibility they are clogged.

If the issues persist or the noises coming out of the air purifier are rattling or grinding then it is recommended to call customer service. This is basically indicating that the air purifier is faulty.

2. An Air Purifier is Operating at a Reduced Speed or with Intervals

If your purifier is working with a reduced speed then in this case, the appliance might benefit from a basic reset procedure.

An Air Purifier is Operating
  • It is suggested to turn off the air purifier for a minute and then turn it on.
  • Following this, assess the unit when it is powered on for proper functionality.
  • If this step proves ineffective, power off the air purifier.
  • Then attempt to connect it to a different power outlet.

This is recommended in case the issue arises from the current power source.

3. Filter is Jammed

Air purifiers utilize HEPA filters to clean indoor air. The airborne particles collect over the filters and after some usage, the filters can be clogged.

Filter is Jammed

Read also: 12 Benefits of Air Purifier: Check Why it Best for Clean Air

The good thing is most machines come with lights that indicate filter replacements. Hence it will turn on when needed. You must change the filter to keep the air purifier running.

4. Unpleasant Smells Despite the Air Purifier Running

If you notice no pleasant smells then the air purifier is not working properly. The solution is simple. You need a new filter as the old one might have been worn out or may contain mold spores. As soon as you change, you will feel the difference.

How Will You Know if a Filter Replacement is Required?

If the air purifier does not work despite air filter cleaning:

  • Try clearing the vent.
  • Remove any blockage in the air vent way.
How Will You Know if a Filter Replacement is Required

After none of this works, you will need to replace the filter entirely. As I said before some air purifiers have indicators that inform you if it’s time to get the filter changed.


How long does it take to notice a difference with an air purifier?

To notice a difference with an air purifier it takes 30 minutes to an hour. However, this can fluctuate depending on the size of the room and how powerful the air purifier is.

How do you know if the HEPA filter is working?

To know if the HEPA filter is working, check the airflow of the air purifier and the filters. Alternatively, you can monitor through the air quality indicator devices.

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Summing up how to tell if the air purifier is working and improving air quality, there are a few things you can do. Firstly put a hand in front of its vent and feel its airflow. It should be consistent, otherwise, the machine must have issues.

Alternatively, you can check the filters. If they are clogged or there is any debris, then clean them up. The operational noise can also tell you. No noise means the air purification system is not working, and loud thuds, or rattling also means that there could be some problem with your device.

Lastly, you can fix issues with your purifier by cleaning it thoroughly, opting for a reset, and replacing its filter.