What is Clean Air Delivery Rate (CADR)?

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.

Follow The 2/3 Rule:

You'll always want a unit with a tobacco smoke CADR at least 2/3 your room's area (square feet - sqft). For example, a 10ft x 12ft room -120 square feet - 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 8ft, you'll want an air cleaner rated for a larger room.

Note: Not all air purifiers and air cleaners sold in the marketplace are certified by the AHAM process and given a CADR rating. The AHAM certification process is voluntary for manufacturers to participate in and they are not required to submit product for testing. This does not mean that if an air purifier does not carry an AHAM CADR rating that it is not a good air purifier, but that it has not been submitted to AHAM for testing. There may be various reasons per manufacturer for that. It makes it easier to compare air purifier performance when they are certified and rated, but most air purifiers on the market (even some of the top rated air purifiers) have not gone through the AHAM process.

Courtesy of: The Association of Home Appliance Manufacturers (AHAM) - A Consumer Advocate Group