A to Z Guide on HEPA Filter- Full Form, Size, Working, Price, HEPA Air Purifier 2020

If the body is an Air Purifier, the heart is a HEPA Filter. Whenever we talk about the best ways to tackle air pollution, the first thing that comes to our mind is using a ‘HEPA Air Purifier’. 

There are various air purification methods used in air purifiers like Ionisation, UV Action, HEPA Filtration and more. But the most efficient of all is HEPA Air Purification Method.

In this detailed guide, we have covered the complete details of HEPA Filter, its working model, benefits, limitations, best HEPA Purifier in India, etc. 

We are sure that you will have a thorough knowledge about HEPA Filters by the end of this guide and you will be able to choose the best HEPA Air Purifier for your home.

A Real-life Experiment on Artificial Lungs

Before getting into the details, we want you to watch this real-life experiment on artificial lungs made of HEPA Filters.

Dr. Arvind Kumar, Chest Surgeon from New Delhi, India carried out an experiment which is worth watching. This would be a reality check for most of the people living in India.

Credits: Lung Care Foundation

What is HEPA Filter | Understanding Basics

Let’s understand the basics of this air filter. HEPA filter is a special type of filter that captures microscopic foreign particles like dust, pollen, pet dander, bacteria, mold spores, smoke, the particulate matter which are main components of outdoor air pollution. 

HEPA Filter Full Form

HEPA stands for High-Efficiency Particulate Air. It is being used to filter out air pollutants since decades.

“HEPA filters were used for the first time in World War II by American scientist to capture radioactive particles that were released during the creation of the atomic bomb”

HEPA Filter Size

Talking in terms of its efficiency, it can trap 99.97% of particles up to size of 0.3 microns. The HEPA Filter size depends on respective Air Purifiers. 

What is the relevance of 0.3 microns? and why not any other number?

As per scientists, 0.3 micron size is the most penetrating particle size. It is found that particles of 0.3 micron size evade air filters more than particles of low as well as higher size than 0.3 microns. So, it becomes mandatory to block particles of this specific size.

Benefits of HEPA Filter

As other air purification methods like ionisation involves harmful ozone gas as a byproduct, it is strictly not recommended. 

Air Purification through HEPA Filter is one of the most efficient and effective ways. This method is recommended by doctors, environmental protection agencies and trusted for filtering out harmful pollutants.

This being one of the most preferred air purification methods even by doctors and air experts, it’s super beneficial. 

How Does HEPA Filter Work | Working Model

HEPA filters consist of interwoven glass fibers that are twisted and turned in multiple directions to create a fibrous filter. This HEPA filter does not allow any particle more than 2.5 PM size to pass through it. 

Their working is quite simple. HEPA Filters work by forcing air through a fine mesh that traps harmful particles such as pollen, pet danger, smoke, dust mites, etc.

As they enter the pre-filter where the larger dust particles are filtered out, they get ready to pass from the HEPA Filter. The circulation is explained below –

How HEPA filters work

In short, the larger sized particles are stopped by direct impaction, while particles of small size try to escape through the gaps which eventually stick to the next fibrous filter by interception and diffusion.

In Layman’s term, HEPA Filter works by forcing incoming air through a very fine mesh that traps all the harmful particles up to size of 0.3 micron

Generally, HEPA filters are used in combination with activated carbon filters which act as a pre-filter to HEPA membrane due to which more targeted air filtration can be obtained. 

A research published by Lung India has confirmed that HEPA filters proved to be beneficial and help in enhancing the Indoor air quality, thereby reducing risk to lives.

What is the difference Between HEPA-like and True HEPA?

The main difference between HEPA-like and True HEPA is their Filtration efficiency. HEPA-like Air Filters are like not HEPA but similar to HEPA Filters. 

It’s like first copy, therefore you need to check Filtration efficiency of your HEPA Filter.

Efficiency Rate

0 %
HEPA-like Filter
0 %
True HEPA Filter

Particle Size Filtration

0 µ
HEPA-like Filter
0 µ
True HEPA Filter

µ = Microns | 1000µ= 1mm

There are various classifications of HEPA filters used in the market. 3 different types of HEPA filters used in the Market are:

You might get confused between these 3 types. But remember that the True-HEPA filter is the best filter you must prefer while buying air purifier. So check for this term while buying your HEPA Air Purifier and also check the Filtration Efficiency.


HEPA Like, HEPA Type

Limitations of Normal HEPA Filter

Normal HEPA Filters in HEPA Air Purifier has 3 limitations. It cannot remove:

Therefore, you should either use True HEPA filters specially treated with Purification technologies.

These specially treated True-HEPA Filters with Ultra Filtration technology are also called Hyper HEPA Filters which can trap and eliminate as small as 0.1 microns of dust, gases, bacteria, germs & viruses.

Some of these Air Purifiers are also tested for removing H1N1 Swine Flu Virus & Influenza Virus.

Moreover, a combination of True HEPA Filter and Activated Carbon Filter is always advisable as the carbon filters have the ability to filter out the foul odor or the bad smell including fart smell and tobacco smoke smell.

What is HEPA Air Purifier?

Air Purifier which uses High-Efficiency Particulate Air (HEPA) filter for Air purification is called HEPA Air Purifier. 

These purifiers may have HEPA as a stand-alone technology or even a combination of 2-3 air filtration technologies to give the best quality of air (by balancing the drawbacks of all air purification technologies)

Best HEPA Air Purifier to buy in India

Considering the Quality, Performance, Price and the benefits of all the technologies used in Air Purifiers, we have selected the best HEPA Air purifier for your home/office. These Air Purifiers are specially handpicked for people having dust allergies and asthma.

Mi Air Purifier 3

MI Smart Air Purifier 3

Specifications of MI Smart Air Purifier 3

(Recommended for low budget buyers)

  1. It is a True Hepa Filter Air Purifier
  2. It consists of Carbon Filter for pre-filtration 
  3. Effectively traps PM2.5 particles
  4. MI Air Purifier 3 has a high Clean Air Delivery Rate (CADR) 
  5. Changing the filter is a simple process (can be done at home)
  6. Effective coverage of your complete area
  7. It prevents dust and eliminates mold
  8. It eliminates allergy-causing elements of air
  9. Real-time data of Air Purification can be seen on the display panel
  10. Highly Trusted brand
  11. Durable and affordable product
Coway Sleek Pro AP-1009

Coway Sleek Pro AP-1009

Specifications of Coway Sleek Pro AP-1009

(Must buy Value for Money Product)

  1. Coway is the World’s Best & Most Trusted Air Purifier Brand
  2. Multi-Layered HEPA Filter effectively traps PM 2.5 particles allowing only clean air to pass through Optimized Airflow
  3. Unique Air Filtration Process- Pre-Filter, Patented Urethane Carbon Filter (To Deodorize the air)
  4. Only Air Purifier with 5 Years of Warranty (others have only 2 or 3 years of warranty)
  5. Real-Time Air Quality Indicator
  6. One-Touch Air-Speed Adjustment
  7. Only Air Purifier with Longest HEPA Filter Life: 8500 hours (most imp filter for any purifier)
  8. Longest Filter life means low cost of maintenance than others
  9. It requires 15-18 months to change filters (almost 6 months more durable than others)
  10. Filters are easily available on Amazon (no wasting time searching for filters)
  11. Air Purifier Coverage Area comparatively high: 355 sq. ft
  12. Clean Air Delivery Rate per hour is also high
  13. Super Silent Operation (Must)
  14. Equally traps bacteria & viruses due to Green Anti-flu HEPA Filter
  15. Highly cost-beneficial air purifier (value for money!!)

Specifications of Philips AC1215/20

(Recommended for Sensitive Groups)

  1. This is a perfect air purifier that can be good for your household use. 
  2. It has 4 Stage Filtration process through pre-filter, activated carbon filter & double layered H13 Grade True HEPA Filter that removes harmful particles of 0.3 microns
  3. It removes 99.99% pollen and house dust mites also it is Allergy-friendly quality tested by ECARF
  4. It is equipped with pre-filter, activated carbon filter and HEPA layer 1 and 2 for the sake of quality air purification
  5. A great quality product is favorable for sensitive groups like Pregnant women, babies, allergic people, asthma patients, senior citizens, etc.
  6. It removes pathogens germs, bacteria, Viruses (tested for H1N1 Swine Flu Virus)

Best HEPA Air Purifiers

(Top Recommended)


To sum up, HEPA Filter is a mandatory filter that must be present in your Air Purifier. Don’t use any Air Purifiers other than HEPA Purification Method as they are not recommended due to health risks.

All the Air Purifiers present on our website use HEPA filters so you don’t have to worry about any Air Purifier.  Do check out the list of best Air Purifiers here.

Best Air Purifier using HEPA filter in India are Coway Sleek Pro AP-1009, Philips AC1215/20, Mi Air Purifier 3

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