CADR – What Is It?
CADR stands for Clean Air Delivery Rate and is the number value assigned to an air purifier on the basis of a set of independent tests that are conducted for AHAM (Association of Home Appliance Manufacturers). AHAM started measuring and assigning CADR to air purifiers during the 1980s.
According to the information found on Wikipedia, CADR is defined to show the filtered air that can be delivered by portable air purifiers. This parameter is indicative of the extent to which the pollen, dust and tobacco smoke are reduced in the ambient air by the air purifier. The CADR thus serves to provide an objective standard on the basis of which a buyer can evaluate the performance of an air purifier.
Since the market is currently flooded with a variety of air purifiers, a standard like CADR is almost a necessity. CADR (as classified and validated by AHAM) values are assigned on the basis of final results after the removal of particles by the air purifier and are not dependent on the technology used: ionizer, HEPA filter, etc.
How Is CADR Determined?
The CADR value is assigned to an air purifier using a process that is easy to understand. It is based on the ANSI/AHAM AC-1 Standard. The rating is assigned on the basis of the following test:
First of all, the amount of air contaminants is measured in a testing chamber of 1008 cubic feet. Thereafter, the air purifier is placed in the chamber and is activated for about twenty minutes, and the level of contaminants is checked. At the end, the reduction in the amount of contaminants is compared to their natural decay rate. After completion of the test, a CADR value is assigned to the portable air purifier unit.
The explanation of CADR as per the EPA is as follows: CADR is the number that indicates the amount (in cubic feet) of clean contaminant-free air that is delivered by the portable air purifier in one minute. As an example, a CADR value of 250 (for dust particles) for an air purifier indicates that the concentration of the contaminant is being reduced by the air purifier to the same extent that would occur if you introduced a volume of 250 cubic feet of clean air in just one minute.
CADR Ratings: Dust , tobacco Smoke, Pollen
AHAM assigns three CADR ratings for air purifiers. These ratings are assigned for the effectiveness of the air purifier in reducing three common indoor contaminants, namely, pollen, dust and tobacco smoke. AHAM recommends the following rule of thumb when selecting an air purifier. The portable air purifier should have a tobacco smoke CADR which is at least two-thirds (2/3) of the area of the room in which the purifier is going to be placed.
CADR ratings – Maximum values
The following are general CADR ratings for common indoor pollutants: dust particles: 10-400 CADR, pollen: 25-450 CADR and tobacco smoke: 10-450 CADR.