Clean Air Delivery Rate (CADR) Explained

If you have begun researching and shopping for an air purifier, I would imagine you have come across the acronym CADR, which is short for Clean Air Delivery Rate.  I’d like to break this down a bit for you and make this statistic is something that you can understand and more importantly use while you look for the purifier that is right for you.

Specifications of the CADR (Clean Air Delivery Rate)

In the early 1980’s, the Association of Home Appliance Manufacturers or AHAM created a standardized way to test portable home air cleaners for their ability to remove particles from the air.  The test puts a given air purifier up against smoke, dust, and pollen and sees how it does at removing particles in a sealed chamber of a size determined in the test’s guidelines (1008 cubic feet).  The results indicate the ability of the purifier to remove smoke, dust, and pollen particles of .10 to 11 microns in size from the air.

There are a few important things to know about the results.  One is that the test does not take into account what type of filtration methods are used by a given air cleaner.  It could be True HEPA filtration, HEPA-type/like filtration, ionization, electrostatic, or any combination of the above.  The standards of the test also provide a maximum CADR result of 400 for dust and 450 for pollen and smoke.  These means should you see a result higher than this claimed by a manufacturer (which I personally never have), it is not accurate or valid per the standards and methods of the AHAM test.  Additionally, whole house purification systems (as in those ones that are incorporated into the duct work of your home) can’t be accurately assessed with this test and keep in mind that the results pertain only to particle removal and not odors, gaseous contaminants, toxins, ozone, microorganisms, or sound.

Is CADR Worth Paying Attention To?

Recognized as an industry standard by the FTC, EPA, and the Consumers Union this test has validity and is worth paying attention to as a consumer.  AHAM performs this assessment as a third party, in an independent laboratory.  Those manufacturers who participate, must put a seal/label on the outside of the box with the ratings (see image below).  This easily visible information can help you comparison shop and inhibits the ability of the manufacturer to make false claims as to the purifiers capabilities.  As recommended by cadr.org, you should look for a CADR for smoke of at least 2/3 the recommended room square footage (for smoke).  While they do not specify for dust or pollen, it seems that you can’t go wrong sticking with the same rule as well.