What is HEPA Air Purifier? Pros & Cons of HEPA Air Purifiers

What is HEPA Air Purifier
Photo: smartcleaningtips.com

HEPA is a household name for the majority out there, as it is a frequently placed prefix with the house cleaning devices such as vacuum or air purifiers.

We all agree on the fact that the air which surrounds us is contaminated by various pollutants.

For the sake of making air worth breathing, HEPA air purifiers do the job of making air clean for us by catching the pollutants suspended in the indoor air with the aid of various filters.

Let us dig deep to know what exactly does it mean? And how it works alongside the major pros and cons?

What Is HEPA Air Purifier?

In simple words, HEPA air purifier is a device which uses HEPA filter to clean the air.

It traces its history back to World War II when scientists based in America designed HEPA filters to capture airborne radioactive particles. The commercial use of HEPA filter started in the second half of the twentieth century.

HEPA stands for High Efficiency Particulate Air. HEPA filters are able to capture small particles such as dust, pet hairs, molds, and pollen while large particles are removed to near perfection.

HEPA Standards

Minimum standard set for the HEPA filter is that it must purge the air at least 99.95% (European standard) or 99.97% (US standard) of particles with a diameter equal to 0.3 microns.

In the market, you would generally notice words like HEPA-like, HEPA-type or True-HEPA associated with the air purifiers. They might sound the same to you but in reality they are not.

The true-HEPA is supposed to meet the prescribed standard mentioned above at all costs and have to purge the air with that precise accuracy.

On the contrary, it is less likely that HEPA-like, or HEPA-type air purifiers meet the same standards. In other words, they are inferior to true-HEPA in effectiveness and are not able to strip air of the pollutants like true-HEPA does.

You shall seek out true-HEPA when you aim to buy one for your home.

How Does HEPA Air Purifier Work?

How Does HEPA Air Purifier Work
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HEPA air purifier does the job of removing particles by passing air through various filters. The filter is made of glass fibers which are twisted and turned in myriad directions to create a fibrous web.

This fibrous web becomes capable enough to strike down airborne particles and at the same time, keeps good check of not releasing them back to the air.

Like any air purifying techniques, fan and filtration system are the two main components of the HEPA air purifier.

The role of the fan is to regulate the air by sucking it inside and blowing out after pollutant-free air.

Filtration System Process

Filtration system of the HEPA air purifiers complete the process in four steps to make sure that particles are trapped when traveling through the fiber web.

  1. Direct impaction: certain large contaminants such as dust, mold, and pollen stick to the fiber when it comes in direct contact.
  2. Sieving: particles which are carried away with the air between two fibers are checked effectively as the gaps are smaller than particles.
  3. Interception: air is capable enough to reroute around fibers, but the particles on their way are ensnared by the sides of the fiber.
  4. Diffusion: ultrafine particles which escape the initial colliding are likely to collide with gas molecules and stick to the fiber at this stage.

By channeling the air in your indoor through these fine mesh maze, you are likely to get rid of the majority of the pollutants that are disturbing the pure air.

Pros and Cons of HEPA Air Purifiers

Let’s take a look at some pros and cons of HEPA air purifiers:


  1. Very efficient, removes the most toxic contaminants.
  2. Keep good check of trapped particles from going back into the air.
  3. Able to capture a lot of dirt like Pollen, mold spores, fungi, dust, pet dander, hair, mold spores.
  4. HEPA air purifier may be called as antivirus HEPA air purifier, because the installed HEPA filters prevents the spreading of airborne bacterial and viral organisms.
  5. It is especially good for asthma or allergy-suffering patients because of its capacity to capture airborne contaminants to an excellent degree.    
  6. Because of its high effectiveness, HEPA air purifier plays a role in other industries as well such as hospitals, aircraft, cars, or laboratories.


  1. HEPA filter falls short of the target for some pollutants such as Volatile Organic Compounds (VOCs), gases, fumes, or odors as the molecules are too small to be trapped.
  2. They require proper maintenance and replacing filters could be costly.


While there is general agreement on air pollution, many people unwittingly ignore the fact that air inside their homes can be just as polluted as outside.

In the wake of this bitter reality, HEPA air purifier provides the relief if used properly.