How Often Do You Change Air Purifier Filters? Detailed Guide

People with allergies or asthma often suffer from these conditions due to air pollution. To breathe better, they have a simple yet expensive device – the air purifier. But this is not enough – they also need to change filters regularly.

There are several kinds of air purifiers, and each one needs a different type of filter that can easily be replaced. The most common ones are Pre-Filters, HEPA filters or Activated Carbon Filters. The latter absorbs gases and odors by using active carbon granules that trap chemicals within its mass. It has two stages of filtration: primary and secondary. A fine particle filter (1st stage) removes larger airborne particles such as dust, pollen and pet dander from the air. The true HEPA filter (2nd stage) purifies the air that passes through it, trapping 99.9% of particles down to 0.3 microns in size.

The frequency of changing a filter varies from one air purifier model to another and depends on the volume of pollutants within your home or office. If you suffer from allergies or asthma, you should get new filters every 3 to 6 months (for HEPA filters) and change Pre-filters more often. Otherwise, if no one has such issues but still wishes to breathe cleaner air, it would be better to do routine filter changes once or twice per year.

Bad quality filters not only fail to clean the air spread contaminants back into your house. If you’ve been using a filter for a long time and the air quality hasn’t improved, it should be replaced immediately.

Related Post: How Long Does It Take An Air Purifier To Clean?

Filter Replacement Schedule

Our guide will help you to learn how to use the best air purifier filters for your home.

HEPA filter

Change every 6-12 months or when you begin to notice a decrease in the purifier’s performance.

Carbon/Odor remover

Replacing filters on purifiers paired with these types of filters is unnecessary since carbon granules lose their chemical properties after some time. However, if they are pre-filters, then it’s recommended to change them monthly or when they are half-filled with dirt.


Depending on the size of the particles in your house, try to replace this filter once every 1-3 months.

To summarize:

  • The more often you use your air purifier, the more often you need to change its filter.
  • If someone in your house suffers from allergies or asthma, it’s recommended to replace filters every 2 months on average.
  • Also, if you wish for a pure air environment and there aren’t a lot of pollutants around, change your filter once per year.
About Maria A. Davis

Hi, I am Maria A. Davis and I am a loving mother and a dedicated reviewer for I tried and tested a number of air purifiers and humidifiers on the market to improve indoor air quality. I created this guide from my knowledge and personal experience so you can improve the air quality in your home and office.

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