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What is a HEPA Filter?

Derek Hales

Written By: Derek Hales

Updated on:

If you breathe air, chances are you’ve thought about the quality of the air you breathe at some point in time. Maintaining healthy air quality is important to help prevent the spread of allergens, germs, and other airborne illnesses.

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In the world of dirty air, there are air purifiers- designed to clean the air you breathe.

A HEPA air purifier is one of the most popular kinds of air purifiers, designed to remove airborne particulate and bacteria using HEPA technology as the primary filtration.

What does “HEPA” stand for?

HEPA” stands for “high efficiency particulate absorber”. Basically, a HEPA filter is designed to effectively absorb small, airborne particles and trap them in the filter.

True HEPA vs. HEPA-like vs. HEPA-style

Some air purifiers have HEPA type filters and some have TRUE HEPA filters. A fancier name, but is there really a difference?

Actually, yes.

By definition, a true HEPA filter can capture up to 99.97% of particles as small as 0.3 microns.

This value is determined by the U.S. Department of Energy and helps to ensure that all HEPA filters on the market perform at the same level.

True HEPA vs. HEPA like - air purification

Thanks to this standard, it’s easy to know that any filter which performs worse than the data listed above is not a true HEPA filter.

Important Note: One popular term in the world of HEPA impostors include “HEPA-like” or “HEPA-style”. These are marketing terms that make a product look like a HEPA filter, but without meeting those strict standards.

“HEPA-like” or “HEPA-style” filters will only be able to capture approximately 99% of particles that are 2.0 microns or larger.

As a general rule, smaller particles can pose a greater risk. Their smaller size allows them to stay airborne and more easily make their way into your respiratory system more easily.

How do HEPA filters work?

When a HEPA air purifier is originally placed in the room and turned on, it begins to start sucking air in. As particles are drawn through the purifier, they begin to interact with the HEPA filter.

Dyson fans - air purifiers

The HEPA air filter is made from fibers that create a barrier that air can pass through, but larger particles cannot.

As air passes through the filter, larger particles are absorbed into the filter and clean air passes through.  

HEPA filters can be permanent or removable. A disposable HEPA filter is made up of a dense paper-like product and will degrade over time and need to be replaced

True HEPA filters stop particles from traveling into clean air

On the other hand, a permanent HEPA filter will likely last the lifetime of the purifier, but not without a little maintenance.

To clean a permanent mesh HEPA filter, you can use a soft microfiber cloth or use a soft dusting brush attachment on a vacuum.

Many vacuum cleaners include HEPA filters within the vacuum itself, helping to removing fine debris while you clean. The Dyson V10, V8, and V7 all include a washable HEPA filter.

The filter on the V7 is located on the top of the radial cyclones
The filter on the V7 is located on the top of the radial cyclones

RELATED – See our full list of vacuum cleaner reviews here.

Even many robot vacuum cleaners are commonly including HEPA filters (though usually not true HEPA).

HEPA filter on the iLife A7 robot vacuum
HEPA filter on the iLife A7 robot vacuum

HEPA filters are effective against:

  • Bacteria
  • Viruses
  • Pet Dander
  • Pollen
  • Mold
  • Dust

This guide has a nice comparison of HEPA filter effectiveness vs. Electrostatic vs. Activated Carbon and vs. Ultraviolet purification methods.

The Benefits of HEPA Filters

  • Readily available. HEPA filtration is one of the most popular kinds of filtration found in air purifiers today. If you’re looking for something that is proven to provide cleaner air and abundant on the market, HEPA filtration could be a great option for you.
  • Captures a wide variety of debris. Since a true HEPA filter is able to capture up to 99.97% of particles, it’s highly effective at cleaning the air. This includes airborne particles like pet dander, pollen, and dust mites.

The Disadvantages of HEPA Filters

  • Potentially expensive to replace: Depending on the design, HEPA filters can be a costly expense. While some advanced HEPA filters can last up to two years (like the filters on the Rabbit Air MinusA2), many others are only approved to last about 6 months.
  • Not great for odors: If you’re looking for a filter that can absorb and dissipate odors, you may not be pleased with the performance of a HEPA filter. A filter of this type is just not designed to capture gasses or odors. For the best results at odor-removal, look for an air purifier that includes a carbon or activated charcoal filter, like the Levoit LV-H132 or Levoit LV-PUR131.

How much space can a HEPA filter clean?

HEPA purifiers can come in many shapes and sizes and with a variety of functions.

Depending on the size and price of the purifier, a HEPA purifier can cover anywhere from 50 up to 1,000 square feet of cleanable air.

Small HEPA Filters

Compact HEPA air purifiers: These purifiers are small, portable and designed to go where you go. They are also generally less expensive, and lightweight, but their smaller filters may also mean that they have small cleaning coverage areas. (Average Coverage area: 50 – 200 sf.)

Levoit LV-H132 Air Purifier Filter Removal
3-stage filtration on the Levoit LV-H132 (HEPA shown on right)

An example of a compact HEPA air purifier is the from Hamilton Beach with a coverage value of approx. 140 sq. ft.,  or the Levoit LV-H132 with a coverage value of approx. 86 sq. ft.

Medium Room HEPA Filters

Medium Coverage HEPA air purifiers: Medium coverage HEPA air purifiers are a little larger and designed to purify medium to large-sized rooms. The larger size generally means that they’re too big to sit on a tabletop or counter.

But their larger size also means that they usually have much larger HEPA filter installed in the machine. (Average coverage area: 200 – 500 sq. ft. )

Levoit LV-PUR131 air purifier filters
3-stage filtration on the Levoit LV-PUR131 (HEPA shown on right)

An example of a medium-sized HEPA air purifier is the Levoit LV-PUR131 with a coverage value of approx. 322 sq. ft or the Coway AP-1512HH air purifier with a coverage value of approx. 360 sq. ft.

Large Room HEPA Filters

High Coverage HEPA air purifiers: High coverage HEPA air purifiers are designed to tacked open concept floor plans or very large rooms. These purifiers generally have the largest footprint, but also the largest filter size.

Large filters capturing tiny particulate means that these filters may also last a little longer than the smaller filters since there is more surface area on the filter.

Rabbit Air Purifier Review
6-stage filtration on the Rabbit Air MinusA2 (HEPA shown in middle)

An example of a high coverage HEPA air purifier is the Rabbit Air MinusA2 with a coverage value of approx. 700 sq. ft. or the Austin Air B450B1 medical air purifier with a coverage value of approx. 1500 sq. ft.

Should you Buy a HEPA Air Purifier Filter?

HEPA is a popular type of filter and air purifier. It is affordable and effective at removing 99.7% of particles 0.3 microns or larger.

As potential disadvantages, a HEPA filter won’t be able to address any odors, but that’s not necessarily a deal breaker.

Many times HEPA filter are paired with other types of filters to help improve overall performance. When paired with a carbon or activated charcoal filter, they are better equipped to deal with smells.

The chemical composition of carbon allows for smells and hazardous VOCs to be trapped in the filter, making it a great partner for a HEPA filter.

Want to learn more about the different types of air purifiers?

Check out our guide on the best air purifiers and learn everything you need to know.

Get through the guide and still have questions? We’ve got you covered.

Click here to shoot us a quick message and we can help clarify any questions you could have or help make a recommendation.

About Derek Hales

Derek HalesDerek Hales is the Founder and Editor-in-Chief of He has been featured in Fast Company, Reader's Digest, Business Insider,, She Knows, and other major publications. Derek has a Bachelor's Degree in Business Administration from Kansas State University. Hales has been testing and reviewing products for the home since 2014.

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4 Comments on “What is a HEPA Filter?”

  1. i purcchase a used hunter ionized hepatech air filter , with/ 1 filter . i orderer other air filters & they sent me one filter. . looks like there should be more than 2 filters there was no pamplet or directions w/. can you set me straight on how many i should have . also what results will i get if i run without ionizer turned on,activated ? thanks !

    • I have no idea. I don’t know anything about Hunter air purifiers. This is a question for the manufacturer.

  2. I have an ionic air purifier that releases 8mm negative ions for every cubic centimeter. How many hours shall I let it run in a 200 square foot room and then move it to another room in the house? Thank you for your help. Mary

    • Hi Mary,

      You should reach out to the manufacturer to better understand ideal / safe run time. Unfortunately, we don’t have enough information to safely make a recommendation.