Buying Guide to Air Purifiers


Breathe easy; choosing the right air purifier for your home or office just got a whole lot simpler. Designed to help reduce airborne particulates such as pollen, smoke, pet dander, dust and mold spores and aid in scoring a better night's sleep, the guide to finding the perfect air purifier is right under your nose.

Air Purifiers

What should you consider first in selecting an air purifier?

To begin, the terms air purifier or air cleaner mean the same thing. Familiarize yourself with the following 6 factors when purchasing a freestanding single room unit or a freestanding, whole-house machine to help you select the unit that best fits your needs.

  • Type of removal technology
  • Type of filter
  • Air change/Efficiency rate (ACH)
  • Clean Air Delivery Rate (CADR)
  • Room size

What do you really need to know about these 6 factors?

Type of removal/air cleaning technology
There are four primary types of air cleaning technology to choose from:
  • a. mechanical filtering
  • b. electrostatic air cleaners
  • c. ion generators
  • d. hybrid systems

The goal of each system is primarily the same: clean the air by reducing particles caused by pollution, interior fumes, smoking, dust, pollens, allergens and air borne irritants.

Type of filter
One of the biggest differences between the purifiers is the type of filter that is used. You will want to be aware of the three types.

HEPA (High Efficiency Particulate Air):
This filter removes high amounts of dust, as well as animal dander, pollen and dust mites. True HEPA is certified 99.97% efficient, so look for a model with True HEPA certification. It is important to note that most HEPA filters must be changed annually. Be sure to check on the cost of replacement, or choose a model that can be cleaned and reused.

ULPA (Ultra Low Penetration Air, or Ultra HEPA Filter):
This filter removes 99.97% of dust, pollen, mold, bacteria and airborne particles and is best for removing even the smallest particulates.

Charcoal or carbon filters work to remove larger particles such as those from smoke and odors. These types of filters are often featured as a pre-filter combined with HEPA or ULPA.

Air change/Efficiency rate (ACH)
The ACH rate, or Air Change per Hour, indicates how many times the air purifier will clean the room's air during the course of one hour. For example, 2 ACH means the air will be cleaned every 30 minutes, while 4 ACH means it will be cleaned every 15 minutes. The highest ACH rate is 6; or six complete cleanses per hour.
Clean Air Delivery Rate (CADR)
Now, while the ACH measures how frequently the air will be cleaned, the CADR, or Clean Air Delivery Rate, indicates the volume and speed at which particles will be filtered. Consider purchasing a purifier with a CADR rating that is at least equal to two-thirds of the room size (i.e., a 120 square foot room would require a cleaner with a minimum of 80 CADR rating).
Room Size
While CADR gives you a good rating to work with, it is often advisable to select a model that is meant to work in an area slightly larger than the actual room size you will be placing the air purifier in.