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How to tell if an air purifier is working

By
Updated on November 21, 2023
Written by
James Booth
James has over ten years experience as a content producer and editor. He focuses on writing articles that are compelling, clear and, more importantly, helpful to the readers. He honed his research and copywriting skills working as part of NeoMam Studios, the parent company of HouseFresh.
TL;DR

Checking if your air purifier is doing its job is as easy as one of three tests:

  1. The Airflow Test  
  2. The Filter Test
  3. Using an air quality monitor.

Results will depend on the type of pollutants and state of your environment. However, it is generally relatively fast, and you could be breathing healthier air in a matter of hours

When your purifier runs, it’s not always easy to tell if it’s doing anything. This is especially the case as what the purifier does — remove ultrafine particles from your environment — is not detected by the human eye.

Air purifiers are a fantastic tool in your arsenal for cleaner air. However, the best air purifiers work away in the background to remove environmental toxins. 

While that’s great in theory — we love a silent bit of tech — it may raise your suspicions as to whether or not your air purifier is making any difference. Well, luckily, there are three main tests you can perform yourself to check on your air purifier’s functionality:

1. The airflow test

Like the name suggests, this is an easy test to check on your purifier’s airflow. When your air purifier is working properly, consistent and clear airflow will come from the machine.

✅ If yes, then your purifier’s doing what it’s supposed to do. 

❌ If not, then there’s more than likely an issue.

Additionally, your purifier should be making some noise (though not excessive). If it’s either silent or whirring loudly to blow the air out, something’s gone wrong!

2. The filter test

This is a pretty easy one to carry out, too; it just means checking the built-in filters in your air purifier.

✅ If they are dirty or full, that’s a clear indicator that the purifier’s doing its job. As air filters work by passing air through it — trapping the various pollutants and then expelling the now clean air back out again — this is what you want to see.

❌ If the filters a crystal clear, that indicates an issue. 

Make sure you change or clean your filters when they are dirty. While it’s good to see that they’re doing what they’re supposed to, your purifier won’t work as well if the filters are too clogged up.

3. The air quality monitor test

Finally, if you’re unsure whether your air purifier works correctly, use an air quality monitor. You can tell what difference your air purifier is making (if any) and have access to real-time data that you can measure.

1️⃣ We light a huge incense stick inside our testing room (sized 705 cubic ft), close the door and the window, and let the sick create as much thick smoke as we can. 

2️⃣ Then we use the monitor to track PM1.0ug/m3, PM2.5ug/m3 and PM10.0 ug/m3 every few minutes.

Tip

1. Test the air quality at different times of the day (overnight, when you have a full house and when you know the quality of the air outside is poor)

2. Check your air quality monitor with your air purifier switched off and note the changes

3. Check your quality monitor when the windows are both closed and open.

The top 3 air quality monitors

Having an air quality monitor can be a great tool to go along with your air purifier. In addition to the peace of mind it’ll bring in your home, some (with built-in CO2 monitoring) will also be handy to bring out and about with you — just in case you want to check if you want to go into that crowded restaurant. 

But with so many different ones on the market, which air quality monitor should you get? These are our top three picks:

Model
Best Portable Sensor
Best Sensor for VOC and Radon
Style
Qingping Air Quality Monitor, Indoor Air Quality Meter Detects PM2.5, Temperature, CO2, and Humidity, Smart Air Quality Sensor for Bedroom, A Rechargeable Device with 2 Colors, Smart Home
Airthings 2930 Wave Plus - Radon & Air Quality Monitor, Battery Powered (CO2, VOC, Humidity, Temp, Pressure)
PurpleAir Touch Indoor Air Quality Monitor
Pros
Excellent value for money
The Wave plus has multiple sensors
Excellent for data gathering and exporting
Cons
When on battery mode, switches off automatically after 30 minutes as default
The App connects via Bluetooth so it has to be within range to function
It is not pretty at all
Dimensions
2.52 x 1.81 x 2.17 inches (‎6.4 x 4.6 x 5.5 cm)
4.75 x 4.75 x 1.4 in (12 x 12 x 3.5 cm)
4.25 in x 3 in x 2.25 in (108 mm x 67 mm x 57 mm)
Price
$134.99
$229.27
$209.00
Best Portable Sensor
Style
Qingping Air Quality Monitor, Indoor Air Quality Meter Detects PM2.5, Temperature, CO2, and Humidity, Smart Air Quality Sensor for Bedroom, A Rechargeable Device with 2 Colors, Smart Home
Pros
Excellent value for money
Cons
When on battery mode, switches off automatically after 30 minutes as default
Dimensions
2.52 x 1.81 x 2.17 inches (‎6.4 x 4.6 x 5.5 cm)
Price
$134.99
More Details
Best Sensor for VOC and Radon
Style
Airthings 2930 Wave Plus - Radon & Air Quality Monitor, Battery Powered (CO2, VOC, Humidity, Temp, Pressure)
Pros
The Wave plus has multiple sensors
Cons
The App connects via Bluetooth so it has to be within range to function
Dimensions
4.75 x 4.75 x 1.4 in (12 x 12 x 3.5 cm)
Price
$229.27
More Details
Best Overall
Style
PurpleAir Touch Indoor Air Quality Monitor
Pros
Excellent for data gathering and exporting
Cons
It is not pretty at all
Dimensions
4.25 in x 3 in x 2.25 in (108 mm x 67 mm x 57 mm)
Price
$209.00
More Details

Want to read more about each of the air quality sensors? Well, you’re in luck as we have recently updated our article recommending our favorite six air quality monitors currently available on the market. 

How long does it take an air purifier to work?

So you’ve just purchased and installed your air purifier in your house. It seems to be working and you’ve done the three tests to check. So, how long will it take to start making a difference? 

The short answer is that it’s already working — but it will take some time to make a real difference.

As soon as you turn your purifier on, it will work. However, depending on your main source of pollution, it may take some time before you notice a significant difference. For example, tobacco smoke and odor being cleared from your environment will be more noticeable than ultrafine particles, bacteria and some VOCs. It will also depend on how polluted your home is.

Having said that, a good, high-quality air purifier could have you noticing changes in half an hour. After a few hours, you may see significant improvement in your air quality.

Tip

Before you buy an air purifier, make sure to check the CADR rating

If you’d like to be sure before you buy, all air purifiers are rated by the Association of Home Appliance Manufacturers (AHAM). This rating is independent and can help you to understand how well your chosen air purifier may perform in your home or workplace.

This rating is known as the Clean Air Delivery Rate (CADR) and is a score given to the appliance judging by how well it can remove dust, pollen and smoke — three of the most common air pollutants.

The higher the volume of clean air that is emitted when the purifier is used against these pollutants, the higher the score. This is, therefore, a helpful way to ensure the air purifier you invest in will be fit for your purpose.

In conclusion

If you’re not sure if your air purifier is working, you can use the three handy tests outlined in this article to check. Remember, these are:

  • The Airflow Test
  • The Filter Test
  • Using an air quality monitor.

Regardless of whether or not you use the other two tests, an air quality monitor can be a convenient gadget to have on hand — especially if it’s portable or has a built-in CO2 monitor!

Finally, it will vary as to how quickly you notice the positive effects of an air purifier. This will depend on the type of pollutants and state of your environment. 

However, it is generally relatively fast and you could be breathing healthier air in a matter of hours. Remember to pay attention to your potential air purifier’s CADR so that you can confidently purchase and know that the device will be effective in your home or workplace.

Last update on 2024-02-21 / Affiliate links / Images from Amazon Product Advertising API

About the author

James Booth

James has over ten years experience as a content producer and editor. He focuses on writing articles that are compelling, clear and, more importantly, helpful to the readers. He honed his research and copywriting skills working as part of NeoMam Studios, the parent company of HouseFresh.