Hepa Air Purifiers

HEPA Air Purifiers are those air purifiers that use HEPA air filters in them. The acronym HEPA stands for various things that mean the same thing like,

High-Efficiency Particulate Air“, or

High-Efficiency Particulate Arresting“, or

High-Efficiency Particulate Arrestance“, or as it originally stood for-

High-Efficiency Particulate Absorber“.

HEPA, basically, is a type of air filter. For an air filter to qualify as HEPA, it must be capable of removing 99.97% of particles in the air having a size of 0.3 microns. Originally used to prevent the spread of airborne radioactive contaminants, the HEPA air filter has since evolved into becoming a household staple.

HEPA is now used in many households cleaning devices such as air purifiers and vacuum cleaners and is even used in specialized fields such as in aircraft and in the bio-medical industry.

How does a HEPA Air Purifier works?

A HEPA air filter is made up of randomly arranged fiberglass fibers that have diameters between 0.5-2 microns. This filter looks a concertina or an accordion of folded paper, that traps particles by three mechanisms, namely interception, impaction, and diffusion.

HEPA Air Filter

For a HEPA filter to purify the air, air has to pass through it. This is exactly, what HEPA air purifiers do. HEPA air purifiers uses a fan or a blower to force air through the HEPA air filter, which filters the air and sends it out.

The more the number of times air passes through the HEPA air filter, the cleaner the air will become. But as air passes through the HEPA air filter, the filter gets accumulated with dust and other particles. Hence, it has to be changed periodically. But most HEPA filters last 2 to 4 years easily.

To put things into perspective, have a look at the below infographic, which shows some of the common air pollutants found indoors along with their sizes.

  • Pollen (5-100 microns)
  • Mold (2-20 microns)
  • Pet hair (0.5-100 microns)
  • Dust (0.5-50 microns)
  • Bacteria (0.35-10 microns)
  • Car emissions (1-150 microns)
  • Oxygen (0.0005 microns)

As is very evident from the above infographics, a HEPA air filter is able to purify most of the commonly found household air contaminants.

HEPA air purifiers are most efficient at trapping airborne pollutants. However, they do not remove odors, gases, fumes and cigarette smoke, and chemicals from the air, as these are much smaller than 0.3 microns. Hence, most HEPA air purifiers use some other technology, such as an activated carbon filter, in conjunction with HEPA air filters, so that they can even remove odors, gases, fumes, and chemicals from the air.

HEPA Air Purifier Buyer’s Guide

Here are some things that one should consider while looking to purchase a HEPA air purifier.


CADR stands for Clean Air Delivery Rate and is a measure of the clean air delivered by an air purifier when operating at its highest speed setting. The CADR rating is given in terms of the amount purified that the air purifier can deliver in an hour and is given as 180 cubic meters per hour, or so.

For faster purification of air, a higher CADR rating is suggested. The CADR is a good way of judging a purifier because it takes into account both the amount of airflow and the efficiency of particle removal. Hence, it helps to differentiate between a high-efficiency air purifier that delivers less amount of air from a low-efficiency air purifier that delivers a lot of air.

2. Air Change Rate

Air Change Rate (ACR), also known as Air Changes per Hour (ACH), tells us the number of times the air purifier can clean all the air in the room in an hour. An air purifier with an ACR of 4 means that the air will be cleaned every 12-15 minutes.

When it comes to ACR, the greater the ACR, the better the quality of the air in the room. However, the ACR will be affected by the size of the room. The same air purifier may operate at a higher ACR in a smaller room than when placed in a bigger room. Ideally, an air purifier should have an ACR of at least 4, but an ACR of 6 or 8 would be even better.

3. Other Technology

Since a HEPA air filter is only capable of purifying airborne contaminants and pollutants, and cannot remove odors, fumes, and chemicals, most HEPA air purifiers use some other technology along with the HEPA air filter to make up for it.

Most HEPA air purifiers comes with an activated carbon filter which helps in removing any fumes, odors or chemicals that are present in the air. Other purifiers use other technologies such as ionizers, UV technology, and Ozone air purifiers.

Ozone air purifiers emit ozone to purify the air. But ozone poses a huge health hazard and is capable of causing breathing problems.

Ionizers produce negative ions to trap particles in the air. Even ionizers are capable of producing ozone. So, if your air purifier uses any of these technologies, you should check if they produce ozone or not. Ideally, a HEPA filter with an activated carbon filter should do the trick for purifying the air.

4. Maintenance Costs

Air purifiers function at their best when they are maintained properly, especially HEPA air purifiers. HEPA air purifiers would require you to change the HEPA filter from time to time. One should have a clear idea about how much replacing the filter would cost and how frequently it should be done. Some HEPA air purifiers come with a pre-filter which can help in increasing the life of a HEPA filter.

5. Power Consumption and Noise Level

Just like any other gadget or device that you have at home, a HEPA air purifier will need power as well. And since an air purifier will be working continuously, it could have a great impact on your electricity bill. It goes without saying that one should look for an air purifier that consumes lesser power while working efficiently.

All HEPA air purifiers have a fan or a blower to force air through the HEPA air filter. Having a fan or a blower would mean that it would produce some amount of noise. And since there’s a good probability that the air purifier will be used in your bedroom, look for an air purifier that does not produce a lot of noise. You wouldn’t want an air purifier that will not let you sleep in peace, would you?

6. Manufacturer Reputation and Warranty

Before purchasing a HEPA air purifier, do a background check on the manufacturer and read reviews by other people. Some manufacturers could make claims which may not be valid or true. Some manufacturers claim to have “HEPA-like” technologies, which are not true HEPA air purifiers, and hence, do not fall for them.

Also, check the warranty that your manufacturer gives on your HEPA air purifier. Air purifiers are long run products and hence, look to get the best warranty on it possible. Also, go through the warranty details and find out which parts like the fan, motor etc. are covered under the warranty.

7. Extra Features

These are the bells and whistles that will make your HEPA air purifier simpler and easier to use. Some features like air quality monitoring are almost a must have, as this feature checks the air quality in the room and adjusts the clean air flow accordingly.

Other Features could include a visual reminder when it is time to change the air filter or a child-lock feature which could prevent children from changing the settings of the air purifier. Audible reminders, LED screens, timers, power saver modes etc. are other features that you could consider.

Top 10 HEPA Air Purifiers

1. Philips 3000 Series AC3256 AeraSense (Editor’s Choice)

Philips 3000 Series HEPA Air Purifier

The Philips AC3256 AeraSense is capable of removing ultrafine particles up to the size of 0.02 microns with 99.97% efficiency.

It does this by using an extra thin HEPA filter which they call as the NanoProtect HEPA filter.

This air purifier can be used to purify the air in a room as big as 95 square meters. This air purifier tops another air purifier due to its wide range of features, advanced air purification, and sustainability.


  • Can be used with a room as big as 95 sq.m. or 1022 sq.feet.
  • CADR- 367 cu.m/hr.
  • Has an activated carbon filter along with the HEPA filter.
  • Certified by AHAM (Association of Home Appliance Manufacturers), ECARF (European Centre for Allergy Research Foundation) and Airmid.
  • Comes with a 2-year warranty.


  • Real-time feedback with a four-step color ring shows the real-time quality of air.
  • AeraSense technology automatically monitors air quality and changes fan speed accordingly.
  • Has an automatic alert for when the filter has to be replaced.
  • Very quiet, especially in the silent mode (only 33 dB).


  • A bit heavy.
  • Doesn’t have a remote control option.



2. Atlanta Healthcare Beta 350

Atlanta Healthcare Beta 350 HEPA Air Purifier

The Atlanta Healthcare Beta 350 is very effective in combating air pollution in Indian conditions. The Beta 350 has a special iCluster technology that uses a seven stage purification process that results in purified air, free of dust, allergens, odors, gases, and chemicals.

The seven stage purification process uses a pre-filter, an anti-bacterial filter, a HEPA filter, an activated carbon filter, a photocatalyst, a UV filter and an ionizer to purify the air of any type of contaminants.


  • Has a coverage area of 350 sq. feet.
  • CADR- 170 cu.m/hr.
  • Comes with a 1-year warranty.
  • ACE (European Conformity) certified product.


  • iCluster technology uses a 7-stage air purification process.
  • Has Super Silence technology, which produces less than 45 dB of noise.
  • Monitors air quality automatically and changes fan speed accordingly.
  • Comes with a filter change indicator.


  • Comparatively poor CADR.



3. Gliese Magic Room Air Purifier

Gliese Magic HEPA Air Purifier

Gliese’s Magic room air purifier has an advanced 5-stage air filtration system that puts this among one of the elite HEPA air purifiers. The 5 stage air filtration system has a pre-filter, true HEPA filter, an activated carbon filter, a UV lamp and an ionizer which produces fresh air free from all sorts of contaminants including smoke, gases, and chemicals.


  • The coverage area of 430 sq.feet.
  • CADR- 140 cu.m/hr.
  • Comes with a one year warranty.


  • Advanced 5-stage air filtration system.
  • Four color air quality indicator provides real-time feedback of air quality.
  • Auto mode automatically adjusts fan’s speed according to room air quality.
  • Ultra quiet, with minimum noise, produced is 25 dB.
  • Portable


  • Very poor CADR.



4. Honeywell Air Touch HAC35M1101G

Honeywell Air Touch HEPA Air Purifier

The Honeywell Air Touch has an advanced 3-stage purification system while covering an area of 450 sq.feet.

The 3-stage filtration system has a pre-filter and a patented HiSiv filter which has a HEPA filter on one side and a honeycomb shaped activated carbon filter that enables it to remove more than 99% of the pollutants. The design itself is an award winning design.


  • The coverage area of 450 sq.feet.
  • CADR- 300 cu.m/hr.
  • Comes with a 1-year warranty.
  • Polycarbonate body with premium finish for durability.


  • Design that ensures zero blind angle air flow.
  • Ozone-free air purifier.
  • Touch panel with air filter replacement indicator.
  • Easy replacement of air filter without the need for service engineer or technician.
  • Comes with a LED air quality indicator.
  • Low noise and low power consumption.


  • Unlike its higher versions, it has no app connectivity.



 5. Mi Air Purifier 2

Mi Air Purifier 2 HEPA Air Purifier

Mi Air Purifier 2 from Xiaomi is a relatively new product but has some great features on offer for a good price. It is an efficient portable room air purifier and has a 3-stage air purification process.

The 3-stage air purification process uses a pre-filter, an activated carbon filter, and a HEPA filter to purify air from all pollutants. The 360-degree cylindrical filter takes in air from all directions and purifies it.


  • The coverage area of 400 sq.feet.
  • CADR- 310 cu.m/hr.
  • 3-stage air filtration process.
  • Comes with a one year warranty.


  • Displays real-time air quality.
  • Automatically adjusts fan speed according to air quality.
  • Smart Controls feature enables connectivity with your phone which can be used as a remote control and also notifies when the filter has to be replaced.
  • Low noise of 30 dB.
  • Energy efficient.
  • Portable


  • No UV lamp.
  • No child lock.

Buy now from the official Xiaomi Site: Mi Air Purifier 2



6. Honeywell Lite Indoor HAC20M1000W

Honeywell Lite Indoor HEPA Air Purifier

The Honeywell Lite Indoor air purifier has a simple, elegant and compact design while producing superior performance.

This air purifier has a 3-stage air purification system including a pre-filter, a HEPA filter, and an activated carbon filter.

Its maintenance is simple and easy and can be done without the need to call for a technician. The Lite Indoor has been designed in such a way that it does all this while using as less power as possible.


  • The coverage area of 250 sq.feet.
  • CADR- 210 cu.m/hr.
  • ABS polycarbonate body with an anti-UV coating for durability.
  • Comes with a one year warranty.


  • Compact yet powerful.
  • Touch panel with child lock, timer, and other functions.
  • Produces noise lower than most ceiling fans (30-50 dB).
  • Easy filter replacement which can be done by anyone.
  • Has filter replacement indicator.


  • No automatic monitoring of air quality.
  • Coverage area is only 250 sq.feet.



7. Philips 1000 Series AC1215/20

Philips 1000 Series HEPA Air Purifier

The Philips 1000 Series AC 1215/20 air purifier is a very effective air purifier, which uses only a NanoProtect HEPA filter to purify the air.

Philips uses its very own NanoProtect HEPA air filter along with VitaShield IPS technology to purify air from particles as small as 0.02 microns.

This air purifier can be thought of as a lower version of the 3000 Series AC3256 AersSense by Philips. But it still offers high performance with many smart features at a pretty good price.


  • Coverage is of 63 sq.m.
  • CADR- 270 cu.m/hr.
  • Certified by ECARF and Airmid.
  • Touch UI with the display.
  • Comes with a 2-year warranty.


  • 4-step color real-time air quality feedback.
  • Night sensing mode makes the air purifier continue doing it works but quietly.
  • Comes with a child-lock feature.
  • 100% ozone-free.


  • 1-stage HEPA purification system means that it cannot deal with gases and odors adequately.



8. Moonbow AP A8400UIN

Moonbow AP A8400UIN HEPA Air Purifier

The Moonbow AP A8400UIN is an ideal air purifier for homes and offices. It is a compact and complete air purifier which is power by a Puri5 technology to purify the air.

The Puri5 technology is a 5-stage purification process which uses a pre- filter, a HEPA filter, an activated carbon filter, a UV lamp, and an ionizer which they like to call as a Refreshing energizer.

The Puri5 technology is more than capable of producing fresh and clear air and can cover up to 400 sq.feet.


  • The coverage area of 400 sq.feet.
  • CADR-215 cu.m/hr.
  • Comes with a one year extended warranty.


  • Puri5 technology enables it to purify the air of any type of pollutants including germs, bacteria, pollen, gases, and odors.
  • Very light, portable and compact.
  • Low noise production.
  • Comes with a filter replacement indicator.


  • No air quality indicator.
  • No auto mode.
  • No remote control.



9. Atlanta Healthcare Alfa 351

Atlanta Healthcare Alfa 351 HEPA Air Purifier

The Atlanta Healthcare Alfa 351 is an air purifier suitable for homes and offices and can cover an area of 350 sqm. feet. It uses a similar iCluster technology to that used in the Atlanta Healthcare Beta 350.

This is a budget air purifier and hence lacks the sophistication of the Beta 350 and hence, uses a 5-stage purification system instead of the 7-stage purification system.

The 5-stage purification system consists of a pre-filter, a HEPA filter, a cold catalyst, an activated carbon filter and an ionizer.


  • The coverage area of 350 sqm. feet.
  • CADR- 100 cu.m/hr.
  • Comes with a 1-year warranty.
  • Has a LED display screen.


  • Portable and compact.
  • Comes with a remote control.
  • iCluster filtration system.


  • A poor quality CADR.
  • No UV lamp.
  • Bit noisy.



10. Gliese Compact Air Purifier

Gliese Compact Air Purifier

The Gliese Compact Air Purifier, as the name suggests, is a compact yet powerful and very efficient air purifier. It comes with a four level filtration system that uses a pre-filter, a HEPA filter, an activated carbon filter and an ionizer.

This has a 360 degrees purification technology, which enables it to purify air from all around it.


  • The coverage area is of 200 sq.feet.
  • CADR- 130 cu.m/hr.
  • Come with a one year warranty.


  • Compact and portable.
  • High CADR for such a small air purifier.
  • Comes with a 3-button touch panel which makes it an easy to use the air purifier.


  • No air quality and air filter replacement indicator.
  • Not suitable for big rooms.
  • No UV lamp.




In conclusion, look for a HEPA air purifier that can cover a bit more area than your room. This way you can use your air purifier at a lower speed and it will be able to do its job more efficiently.

If you are looking to use the same air purifier for various rooms, look for one that is compact, portable and easy to move.

Having said that my recommendation to anyone looking to buy a HEPA air purifier would be the Philips 3000 Series AC3256 AeraSense, for its brilliant features and not to forget the fact that it comes from a trusted brand.


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