Air Purifier

Buying Guide for Air Purifiers

Want to buy air purifier for your home but not able to decide how to buy Air purifier? You should go through our air purifier buying guide to understand different types of purifiers and things to keep in mind before buying an air purifier.

Air purifiers can be classified either based on purifying technology they are using or based on portability.

What are the different types of air purifiers?

Types of purifiers based on technology

There are essentially five types of purifying technologies. Please keep in mind that air purifiers will often employ more than one purifying technology because no technology is complete in itself

1. Basic and HEPA filters: These are most common filters available in India today. HEPA air purifier remove cancer causing particles such as dust mites, pollens, cigarette smoke, animal skin etc. IT can remove particles of size of as small as 0.3 microns.

This works with help of filters. Therefore you will have to replace the filters every few months depending on your usage.

2. Ozone Generators: Ozone air purifiers work by producing actual Ozone air by charging the oxygen in the air and charging it and converting it into Ozone. Exposure of Ozone can be harmful for asthama patients since Ozone is not good for health.

3. Activate Carbon Technology: This filter works on principle that porous activated carbon with very high surface area can be used to remove particulate matter. The pores trap different types of compounds. It is usually used in addition to existing purifying technology. Also, it is very useful in case your existing purifier is not able to remove the smell in the air. Even these filters have a life span and have to replaced when its life ends.

4. UV technology: It is a powerful way to destroy microorganisms. This technology is also used in water purifiers for the same purpose. Since it is helpful in removing microorganisms such as bacteria and viruses, it used in addition to existing filter technology to combat particulate matter int e air.

Also, this technology works by producing Ozone and destroying germs, purifier should be able to absorb / handle the produced Ozone because Ozone gas itself can be harmful of not regulated.

Therefore it is recommended to change Ozone lamp as per manufacturer’s recommended time frame. Typically, after a air is filtered by HEPA and other technologies like activated carbon, UV is applied in final stages of filtration.

5. Ionizer: Ionizers produce charged particles or ions. The ions charge particulate matter and trap them. They are particularly effective in removing very small particles that HEPA or other filters are not able to filter. Therefore they are used in conjunction to filter technology

Type of air purifier based on portability

1. Pedestal air purifiers: These air purifier can be placed on floor surface and are heavier in weight.

Advantages of a Pedestal air purifier:

  • It is the most efficient type of purifier
  • It has higher CADR and ACH

Disadvantages of Pedestal air purifier:

  • It is typically heavier in weight.
  • It produces more noise
  • It takes more space in the room

Table-Top air purifier: Also call portable air purifiers, these filters are the light-weight air purifiers and are pocket friendly

Advantages of portable purifier:

  • It produces less noise
  • It is pocket friendly
  • It consumes less power

Disadvantages of portable purifiers:

  • It has limited speed settings
  • It usually does not have air ionizer technology or HEPA filters
  • It requires cleaning and maintenance at regular frequency
  • It is sufficient for very small rooms

Wall Mountable: These are smaller and lightweight and made to be mounted on the wall

What to look for while buying air purifier?

1. CADR: CADR stands for clean air delivery rate. It is a measure of speed of delivery of purified air by the purifier at its highest speed setting.

As a general rule, large room size requires higher CADR rating

The Environmental Protection Agency (EPA) has given these guidelines for minimum CADR ratings by room size:

Area (square feet)100200300400500600
Minimum CADR (cubic feet per minute)60130195260325390

2. Noise: Air purifiers produce noise. There you have to be careful of the noise levels of the air purifier before purchasing.

You can typically choose air purifier with higher noise for living room, while bedroom should have purifier with lower levels     

Anything less than 20 db is excellent. 60 dB noise levels are very similar to noise made by AC.

3. Air Change Rate: Also called ACH or Air change per hour, Air change rate is the number of times the entire air in the room is fully purified in an hour.

For example, ACH of 2 means that air is being purified every 30 minutes.

4. Anti- bacterial coating: Presence of anti-bacterial coating in HEPA filters is an added benefit

5. Maintenance and electricity cost: Apart from purchasing cost, Air purifiers use good amount of power. Higher power usually means more efficient purification, and more noise. Therefore you have to maintain a banlance between cost, effectiveness and usability.

Also, filters have to be replaced from time to time. Typical life of HEPA filters is 2000 hours. It means if you are using it for 10 hours per day, then filters will last for 200 days ( 6 to 7 months)

6. Brand: You should try to purchase air purifiers from established brands and zero-in on models with good reviews.  

7. Warranty: You should check the terms of warranty of product carefully before purchasing the air purifier. Check what all parts are covered under warranty.

8. After-Sales Service: Typically established brands will have good after sales service. Also, you should check how many services centers are available in your city. Usually, more services centers are considered good.

9. Other features:

Child-lock: Child lock feature is helpful when you have small children at home. It is a one click feature that helps ensure that the settings are not accidentally changed by kids.

Auto monitoring feature: This feature monitors the air quality and automatically regulates the speed of purification based on the pollutant levels


Air purifiers can be necessary if you are living in large polluted city. It is important to assess the type of air purifier you should purchase before you start looking for air purifier for your home.

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