How Long Should I Run My Air Purifier?

When you have concerns about the quality of the air you’re breathing every day, one of the first things you can do is get yourself an air purifier.

However, there are a lot of things you should know about these devices to make sure they are effective in improving your air quality.

For example, you should know what kind of filters your air purifier works on and replace them periodically.

Furthermore, you should know how long your device should stay on to effectively clean your air.

In this article, we’ll provide information about this: not only we’ll tell you how long you should leave the air purifier on but also why.

How Long Should I Run My Air Purifier?

Key Takeaways

  • An air purifier takes 30 minutes to 2 hours to clean indoor air.
  • When you turn off the air purifier, the air quality goes back to its normal polluted values.
  • To make your air purifying system more energy efficient, isolate your room.

Read: How Do We Review Air Purifiers?

How Long Should You Run Your Air Purifier?

How Long Should You Run Your Air Purifier

The short answer is that an air purifier should stay on 24 hours per day. But why? There are several factors to be considered.

The first is that the air purifier improves the air quality only when it stays on.

As soon as it turns off, unless the room is completely isolated from the external environment, the air quality would go back to its normal polluted values.

The second factor is just as important, but very few users are aware of it: an air purifier doesn’t clean up the entire indoor environment immediately.

It can take from 30 minutes to 2 hours to clean indoor air. Why is this important to know?

If you have an air purifier in the office, or if you have one at home, but you spend half a day in your workplace, you may wonder whether it makes sense to leave the air purifier on 24 hours per day. Can’t you just turn it on when you arrive at home or at the office?

You could, but you need to be aware that for the first 1 or 2 hours, you’d be breathing polluted air.

If you want to find a clean environment when you get home or at work, the air purifier needs to be working for a while.

You could purchase an air purifier with programmable features: for example, you could set the air purifier to turn itself on 1 hour before you get home or to the office.

This is an effective way to optimize the energy consumption of your device. 1

Tips from Reddit users

For how long should you run your air purifier?
by u/superduper30000 in EnvironmentalEngineer

Read: AHAM: What It Is And What It Does?

Read: Activated Carbon Filters

Ways to Make Your Air Purifier More Energy-Efficient


One of the main cons of leaving an electrical appliance always on is that it is going to consume a lot of energy.

We’ve already talked about programmable features, but another way that you can use to make your air purifying system more energy efficient is to isolate your room as best as you can.

Keep windows and doors closed, for example, so that new pollutants or other particles don’t come in. This way, even when the device is off, the air can remain clean. 2

When Should I Turn Off my Air Purifier?

Air Purifiers work effectively when you keep them on 24×7. But you can put the air purifier on low mode during the night if you are tired of its noise.

You can also turn it off if you’re going away from your house for long hours or days.

In case you do not have an allergy or respiratory problems, you can turn it on for some hours during the day or night.

Can Air Purifier Be Kept on the Floor?

You should keep your Air purifier on a bedside table or counter because that way, it is able to take up the air and pollutants closer to the ceiling and is able to clean the air more efficiently and faster. 3

How Long Does an Air Purifier Takes to Clean a Room?

air quality

The timing depends on how large your room is and the setting of the air purifier.

The air in smaller rooms can be cleaned in 30 minutes, while larger rooms can take 2-3 hours. You can buy an air quality monitor to know if your room is cleaned or not. 4


Your air quality would improve only when the air purifier is on. For this reason, you should keep it working 24 hours per day. However, in this article, we’ve seen ways of optimizing its functions.

Read: How Does An Air Purifier Work?

Read: Filter Health Indicator


Will I get a hefty bill if I use an Air purifier for long?

No, you will not! Air purifiers have wattage that ranges between 40W-200W. You can even run the air purifier on 10W-30W low setting.

So you would get $5-$10 of additional bill even if you run in 24×7.

Should I keep my windows closed while using an air purifier?

Yes, keeping the windows closed would obviously make it easier for the air purifier to clean the air of your house and maintain it.

But the best thing is that air purifiers are effective in purifying air even when you have open windows.

Can air purifiers help with allergy?

Yes, air purifiers can effectively reduce air borne particles and dust-containing allergens, so it is very effective in helping with allergies.

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The National Planning Cycles is committed to producing high-quality content that follows industry standards. We do this by using primary sources, such as white papers and government data alongside original reporting from reputable publishers that were appropriate for the accuracy of information while still being unbiased. We have an editorial policy that includes verifiable facts with due credit given where applicable.


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