Understanding AHAM and CADR Charts

How to Interpret AHAM's CADR Ratings

Please note: CADR does not apply to technology that does not use air flow such as Airfree's ceramic core and Vortex's SPI technology.

Certified Clean Air Delivery Rate (CADR) - Recognized by the U.S. Environmental Protection Agency and the American Lung Association, the CADR is independently measured by the Association of Home Appliance Manufacturers (AHAM) to enable consumers to compare air purifiers with regard to performance in eliminating tobacco smoke, dust and pollen.

All of the manufacturers voluntarily participate in the AHAM certification program for room air cleaners. This standardized measurement system - known as the Clean Air Delivery Rate, or CADR - determines how well an air cleaner reduces pollutants such as tobacco smoke, dust, and pollen. From air cleaner to air cleaner, compare the CADR numbers listed next to each model number.
The Association of Home Appliance Manufacturers (AHAM) seal (usually found on the back of an air cleaner's box) will list three CADR numbers - one for tobacco smoke, one for pollen and one for dust. The CADR number indicates volume of filtered air delivered by an air cleaner. The higher the tobacco smoke, pollen and dust numbers, the faster the unit filters the air.

First, look at suggested room size. Then refer to the tobacco smoke, dust, and pollen CADR numbers. The higher the numbers, the faster the unit filters the pollutants out of the air. If from one unit to the other the ratings are the same, their air filtering performance is similar.

In basic terms, the higher the number (rating), the more clean air delivered.

Follow AHAM's 2/3 Rule:

You'll always want a unit with a tobacco smoke CADR at least 2/3 your room's area.

For example, a 10 ft x 12 ft room - 120 square feet (sqft) - would require an air cleaner with a tobacco smoke CADR of at least 80. If your room size is smaller, the unit will simply clean the air more often or faster. If you have ceilings higher than 8', you'll want an air cleaner rated for a larger room.


CADR Performance Measurement Parameters


  Dust                         10 - 400 CADR 

Tobacco Smoke       10 - 450 CADR 

Pollen                        25 - 450 CADR


Example of CADR performance measurement:


  Room Size Calculation

Room size square footage is calculated using the following formula:

Square feet of room = Smoke CADR value x 1.55

This formula is based on the CADR requirement to remove 80% of smoke particles on a continuous steady state basis, assuming one room air exchange per hour.