What Is A HEPA Filter? Working And Benefits Explained!

Do you have an Air Purifier at your home? If yes, you must have heard of the term HEPA Filter. And, if you don’t have one at home, you should buy one. The pollution in India, especially in Delhi is increasing crazily. You must consider buying the best air purifier for your dear ones.

Well, let’s come to the topic, HEPA filter. HEPA stands for High-Efficiency Particulate Air.

HEPA is described as a filter that apprehends 99.97 per cent of bits or particles dropping to 0.3 microns. It is tested using a standard by an association named IEST.

Filters that do not satisfy these stringent test criteria can be less efficient at eliminating possibly dangerous particles from the atmosphere.

HEPA is also known by other terms such as There are other terminologies as well such as High-Efficiency Particulate Absorber, or High-Efficiency Particulate Arresting, or High-Efficiency Particulate Arrestance. However, they are all same.

Let us now study the High Standards of HEPA filters.

High Standards Of HEPA Filters

A HEPA filter used in an air purifier should be sufficient in removing 99.97% of bits or particles from the environment.

A micron is one-millionth part of a millimetre. If you still don’t understand the value, let’s take an example. Take the example of one strand of human hair. It is between 50micron to 100 microns. Any other object that is less than the size of 10 microns in size is not apparent to the human eyes.

Let’s look at the dimension of several airborne particles.

  • Bacteria – 0.3 to 60 microns
  • Car emission – 1 to 150 microns
  • Spores – 3 to 40 microns
  • Mould – 3 to 12 microns

How Does HEPA Filter Work?

HEPA filters are an arrangement of a network of randomly systematised fibres. These are usually composed of fibreglass. The diameter of the filter is between 0.5 and 2 micrometres.

The filter has three key constituents. They are-

  • Fibre diameter
  • Filter thickness
  • Face velocity

The constituent mentioned above highly concerns the function of the HEPA filter. Moreover, the air space between the HEPA filter fibre is more than 0.3 micron.

Working of HEPA Filter

HEPA Air Purifiers- Various Styles And Designs

HEPA air purifiers allow you to choose the best from the hundreds of options. You can fund the product that can suit the decor and theme of the room. Wall-mounted HEPA air purifies allows you to place them anywhere in the room.

Whereas, ionizers are a sleek vertical unit that is supposedly placed in the corner of the room. However, the new ionizers are fashionable and trendy, but they can still not match the looks of HEPA air purifiers.

Many people believe that the HEPA filter just acts as a sieve. A sieve that allows the small particles to pass through them. Whereas, this is disbelief. There is a combination of three mechanisms that work simultaneously. They constitute the working mechanism of the HEPA filter. The mechanism included are-

  • Interception
  • Impaction
  • Diffusion

Therefore, HEPA filters are highly efficient and can even ambush particles less than 0.3 microns as well.

HEPA Filters And There Utility

Initially, HEPA filters were used in the nuclear industry. They were highly helpful in eliminating the dangerous radioactive particles. Later, IQAir took patent over the HEPA filters and used them in air purifiers. Today, HEPA filters are used not just in air purifiers, but also in hospitals and aircraft.

Let us now discuss the Pros and Cons of HEPA Filter

HEPA Filter – Pros & Cons

  • HEPA filters can clean and purify the circulated air
  • They can keep out 99.97% of pollutants equal to or greater than 0.3µm
  • Dust and debris do not have any chance against the HEPA filter
  • It cannot trap pollutants like gas molecules, fumes, chemicals, and odours
  • The cost is an inhibitive factor. Replacing the HEPA filter is an expensive affair
  • The shape and compactness of the unit depends on the kind of HEPA filters you use
  • Some of the HEPA filters are washable whereas others are not.


HEPA is modern technology, especially for INDIA. You get to observe that the vacuum cleaner and air purifier manufacture resorts to marketing tricks. These tricks might include the terms like HEPA-style or HEPA-like. However, it all means the same. They represent the HEPA filters.

But, you should know that they all are not the same. HEPA filters are classified into 5 parts. Ranging from A to E. HEPA-A is the least effective whereas HEPA-E is highly effective.

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