How Long Does An Air Purifier Take To Work?

Last updated on May 12, 2022 FEATURED
Note: This post may contain affiliate links. As an Amazon Associate, we only earn from qualifying purchases!

Air purifiers are one of the best ways to improve your indoor air quality. In fact, doctors recommend the use of air purifiers to avoid respiratory-related issues. However, the question that bothers many people is how long does an air purifier take to work? 

Various air purifier manufacturers have come up with specific time frames their products take to clean the air. But, very few can actually match up the stated time frame whenever they are switched on.

On average a good air purifier can take between 30 minutes to 3 hours. However, there are various factors that can determine how long your air purifier takes to purify the air.

In this article, we have provided a guide on how long air purifiers take to work and the factors that determine their performance.

Factors That Determine The Working Timeframe Of An Air Purifier

As stated above, most air purifiers take between 30 minutes to 3 hours. Though the exact time taken by your air purifier to cleanse your indoor air depends on the factors below.

  • Clean Air Delivery Rate (CADR) Rating

Image showing AHAM verified CADR label
CADR label

CADR is a metric system used to measure the performance of air purifiers. Particularly, it reflects the air volume in cubic feet per minute (CFM) that is cleaned in a given room size. That is to say, an air purifier can clean fast if its CADR rating is at least two-thirds (⅔) of the total area coverage. For instance, for an air purifier that can cover 200 square feet, the CADR rating should be at least 150 CFM for it to clean fast.

  • Type Of Airborne Particulate

No air purifier can be consistently effective on all types of pollutants. Some air purifiers can remove specific impurities faster than others. For example, some models can remove dust in a short time and take longer when removing odors. Usually, most air purifiers show their superiority with a CADR breakdown. In your air purifier specification guide, you may find a CADR rating for dust, smoke, pollen, and others depending on the model.

  • Fan Speed Setting

The higher the fan speed, the lesser the time an air purifier takes to remove indoor pollutants. Most air purifiers have 2 or more fan speed settings. In this case, an air purifier running at a 5-speed setting will purify faster than that operating at 2 or 3.

  • Area Coverage

The covered area also determines the time an air purifier can take to remove pollutants. If the room is wide, an air purifier will take a longer time to work. This time might be shorter when operating in a smaller room.

How To Improve Air Purifier Cleaning Time

  • Replace Filter On Time

Image showing air purifier filter
Air purifier filter

Filters help trap airborne impurities. However, as time passes, these filters lose efficiency. So, to maintain the cleaning speed of your air purifier you need to keep replacing these filters in time.

  • Vacuum or Clean the Floor

Air purifiers can only deal with contaminants suspended in the air. This means dust and other pollutants resting on the surface may not be removed. Challengingly, these might be released back into the air any time you move around. For this reason, you need to clean your indoor surfaces to limit impurities getting released back into the air. Therefore, an air purifier can only remove pollutants floating in the air.

  • Close Doors and Windows

It is good to always close your house or room when using an air purifier. This is because the purified air may move out while more pollutants come in. Certainly, this would make an air purifier work for longer to completely clean the air. Ultimately, by closing doors and windows you limit pollution, thus aiding the air purifier in cleaning the air faster.

Tips To Test If Your Air Purifier Is Working

  • Use Air Quality Monitors

Image showing air quality monitor
Air quality monitor

You can tell whether your air purifier is working or not by using air quality monitors. These detect the current air quality in a room. Some air purifiers also come with built-in air quality monitors. So, these can help measure the current indoor air quality to help you determine whether your unit is working.

  • Check Filters

As discussed above, filters get worn out after some time. A clogged filter may not perform to the maximum. Therefore, if you find molds or pollen clogged on the filters, your air purifier may not be working well.  


Air purifiers can take between 30 minutes to 3 hours to purify a room. However, the time taken for an air purifier to cleanse a room depends on a number of factors. These have been discussed in detail.

If you have read the article all through, we hope your questions have been answered. Below we have also provided some frequently asked questions. These can help you get answers to other questions you might be having.

Frequently Asked Questions

 How long does an air purifier filter last?

This primarily depends on filter type and pollution levels. However, on average filters need to be replaced every 6-12 months. For pre-filters, you should replace them every 3 months depending on your indoor air quality.

How Long Should The Air Purifier Run

Air purifiers should run for as long as there is air pollution. In fact, it is advisable to let your air purifier run 24/7 for effective performance.

How To Use An Air Purifier Effectively?

In case you want to use your air purifier effectively, take note of these factors.

  • You need to frequently maintain your unit by cleaning or replacing the filters.
  • Keep your doors and windows closed when your unit is running
  • Let the air purifier run consistently

Featured Posts

Latest Posts