Informational Guide

How Long & How Often Should You Run an Air Purifier?

Air purifiers are designed to clean your home and can be run 24/7 as long as they are properly maintained. Read the rest of our guide to learn more.

by Josh M

When you purchase a new air purifier, one of the first things you might ask yourself is, “How long should I run an air purifier?”

Running an air purifier all day is something that many people do, and it is more than acceptable. Air purifiers are designed to clean your home and can be run 24/7 as long as they are properly maintained. To get the most out of your new air purifier, read the rest of our guide.

How long it takes for an air purifier to purify a room depends entirely on the size of the room and the exchange rate of the air purifier itself. So, let’s break down this equation. First, look at your air purifier specifications. Then look at the square footage of the room where the air purifier is located.

If your air purifier can purify 240 sq ft in two hours and you have a 480 sq ft room, then it will take your air purifier approximately four hours to purify the room. Most air purifiers take between 30 minutes and two hours to do a full air exchange cycle for the square footage listed on their manufacturer’s instructions.

When purifying large spaces, it is best to use a whole-house air purifier so that the space can make it through several air changes each day. Hotels have begun adding air purifiers as the latest amenity to keep visitors happy.

How Long Should You Run an Air Purifier?

Man Looking at Air Purifier in Living RoomClients often want to know how long they should run their air purifier, but this is really a matter of personal preference. The important thing is to make sure that you run your air purifier for a minimum of six hours so that several air exchanges are completed each day.

We do recommend that most homeowners with allergies run their air purifiers 24/7 if possible and simply change the speed (most air purifiers have eco-friendly, low, medium, and high-speed settings) throughout the day. This is particularly true in the summer when allergens are at an all-time high.

Running the air purifier 24/7 does have numerous benefits, including better air quality, reduction of airborne pollutants, and white noise for anxiety. However, running an air purifier 24/7 also comes with disadvantages, including higher costs and maintenance bills.

Pros & Cons of Running An Air Purifier 24/7

What We Like
  • Better air quality
  • Filters out more airborne pollutants
  • Better control over allergens during summer or when windows are open
  • White noise can help calm anxiety
  • Can move throughout the home (purify multiple spaces)
What We Don’t Like
  • Higher electric bill
  • Higher maintenance cost (replacing filters)

How Much Does It Cost to Run an Air Purifier Per Hour?

The cost of running a home air purifier depends on the type of purifier, the size it purifies, and your personal home electric costs. Most air purifiers cost between $0.10 and $1.00 per day. The bigger the air purifier, the more expensive it will be to run.

This comes to approximately $0.70 to $7 per week and $36.50 to $365 per year. For more information on what an air purifying device can do for your home, Wirecutter made a quick video. For many, the cost of running an air purifier 24/7 year round is far outweighed by the benefits of clean air.

How To Get The Most Out of Your Air Purifier

Leave the air purifier on all the time.

If you leave your air purifier on all the time, you will be able to have the cleanest air possible for your home. The longer your device is left on, the more air exchange cycles occur and the fewer allergens you have in your air.

Leave the air purifier in the same room.

We recommend leaving the air purifier in the same room because it takes time to clean the air from each room. If you move the air purifier frequently, you won’t get as many air cycle changes as you need to have a cleanroom. If you have a large, whole-house air purifier, then you can change it once or twice during the day.

Keep the doors and windows closed.

In order for your air purifier to work efficiently, it is best if you keep the doors and windows closed. However, we do recommend opening your window to vent your room, once per day for a few minutes or weekly for a few hours. Otherwise, you may end up with a stuffy environment. You can shut your air purifier off when you vent the room.

Point the flow of clean air toward the breathing zone.

We recommend pointing the flow of clean air towards the breathing zone.

This means the direction of air flowing out of the air purifier should be moving towards the area where you will spend the most time breathing (middle of the room, couch, table, etc.).

Air Purifier Point of Flow
Replace filters on time

Make sure that you replace your air purifier filters on time. Most air purifiers need to be replaced every two to six months. We recommend checking your air purifier filter every week for a light cleaning to increase the time between filter exchanges.

Avoid air purifiers that emit ozone.

There are air purifiers that emit ozone, and these should be avoided while you are present in the room. Ozone is dangerous when inhaled, and low levels can cause shortness of breath and coughing.

People Also Ask (FAQ)

How long should Honeywell air purifiers run for?

Honeywell air purifiers should run for the recommended amount of time on the instruction manual. This is typically anywhere from six to twelve hours per day, but it is perfectly acceptable to run your Honeywell air purifier 24/7 as well.

How long do Dyson air purifier filters last?

Dyson air purifier filters last approximately twelve months. Therefore, we recommend replacing your Dyson air purifier filter every year.

How often do you change most air purifier’s filters?

Most air purifier filters must be changed every three months to six months. A few models can last up to twelve months. Follow the instruction manual for the best results.

Is it bad to sleep next to an air purifier?

No, it is not harmful to sleep next to an air purifier. In fact, you should end up with better air quality as a result. However, if you have the air blowing directly on your face, you may wake up with a slightly sore throat or stuffy nose.

Can personal air purifiers keep cold and flu bugs away?

No. Personal air purifiers cannot help keep cold and flu bugs away, but they can help reduce the particles and allergens present in your air.

Does an air purifier make air dry?

An air purifier does not take moisture out of the air, so it does not make the air drier. For humid environments, use a dehumidifier as well.


Purchasing an air purifier for your home is one of the best ways to take control of your air quality. It is also one of the most affordable. Even when running your air purifier 24/7, homeowners will only need to spend between $36.50 to $365 per year on their electric bills.

Last Updated on April 3, 2022

Josh M

My name is Josh and I am obsessed with the HVAC industry. I created this website to help HVAC techs of all levels get the best out of their heating & cooling systems. I have spent thousands of hours studying air conditioners, heaters and home air products so you can learn & buy with confidence. Learn more about the team here.