Choosing Your Next Air Purifier

Protect yourself from allergens and contaminants with air purifiers

Air Purifiers Buying Guide

Air purifiers can go a long way in getting rid of fungus, mold, dust and bacteria that can cause everything from sneezing to runny noses to illnesses.

This guide will tell you about the kinds of indoor pollutants that a purifier can help combat, along with the specific types of air purifiers.

Tip: When choosing an air purifier, the size of the room is one of the most important aspects to consider.

Purifier Types

Purifiers can help protect against tobacco smoke and its odors; irritation to skin, eyes and lungs that come from indoor pollutants; and allergy-related symptoms from bold, fungus, pollen and pet dander.

Consult the chart for details about different purifier types.

Purifier Type Effective Against Points to Consider

Activated Carbon Filter

  • Fumes
  • Gases
  • Odors
  • Smoke
  • Removes odors and unpleasant smells
  • Filter will need to be changed when full
  • Not effective against dust, allergens or microorganisms


  • Particulates
  • Some odors
  • Some gases
  • Allergens
  • Collection plates must be cleaned regularly
  • Requires electricity to operate
  • Available in both portable and whole-house configurations
  • Not effective against bacteria and viruses

HEPA Filter

  • Hair
  • Dust
  • Particulates
  • Pollen
  • Spores
  • Mold
  • Some bacteria
  • HEPA stands for “High Efficiency Particulate Accumulation”
  • Removes 99.97% of all particles 0.3 microns or larger in size
  • Filter must be replaced every 12-18 months
  • May be more expensive to maintain
  • Not effective against gases, odors or viruses


  • Particulates
  • Some viruses
  • Bacteria
  • Smoke
  • Causes particles to clump together and fall to the ground
  • Fallen particles may make floors and walls dirty
  • Removes extremely small particles
  • Doesn’t use a filter and has no fan, making operation quieter
  • Not effective against fungus, germs or some viruses


  • Microorganisms
  • Viruses
  • Bacteria
  • Pathogens
  • Mold
  • Organic gases
  • Bulb must be replaced annually
  • Bulb should be cleaned periodically, as per manufacturer’s instructions
  • The longer pollutants are exposed to light, the more effective it is
  • Not effective against particulates, gases or odors

Placement, Performance and Features

Make sure the purifier is suitable for the size room you’re looking to protect, and look for a high clean air delivery rate – the cubic feet of air a purifier cleans per minute.


  • Avoid placing a purifier in a room that’s too large for it to fully cover.
  • Some devices, like UV purifiers, are installed directly into your HVAC system.
  • You may need a purifier for each room you spend time in.
  • Casters and handles make it easier to move portable units around.


  • Improve the effectiveness of your air purifier and extend filter life by using pre-filters that trap large particles before air gets to the main filter.
  • To ensure quality, look for purifiers that have been approved by the Underwriters Laboratory.
  • Filters with larger surface areas are more effective than smaller ones.
  • The clean air delivery rate (CADR) indicates how many cubic feet of air a purifier cleans per minute.
  • The more air changes per hour a machine provides, the higher the quality of air it creates.


  • Multispeed fan: Allows you to increase or decrease the speed to help provide the proper number of air changes per hour in different-sized rooms.
  • Quiet operation: Operates quietly so you can sleep soundly without sacrificing air quality.
  • Automatic timer: Set your purifier to turn on and off automatically.
  • Filter change indicator light: Lets you know when it’s time to change the filter.
  • Personal air purifiers: Battery-operated units that you can hang around your neck to provide personal high-quality breathing space.