Air cleaner testing (CADR testing) How is a CADR Rating Calculated?

How is CADR Rating Calculated for Air Purifiers

There’s a standard test procedure to calculate and assign CADR ratings to air purifiers that’s been pretty much constant over the years. The Association of Home Appliance manufacturers have labelled the following precise test guidelines under the ANSI/AHAM AC-1 standard.

The air purifier is placed in an examination room that measures 1008 cubic feet in volume.

The initial concentrations of separate sized particles are measured and noted before the air purifier is activated.

The air purifier is run for a period of 20 minutes at full fan speed. Throughout this time, the reduction in the concentration of respective particle size categories is evaluated and noted.

At the end of the 20 minutes, the total reduction in the concentration of pollutants is compared to their gradual rate of degradation during the test period.

The testers then assign the CADR rating to the air purifier as a product of filtration efficiency and unit’s airflow.

For instance, if a large air purifier has an airflow of 300 cubic feet per minute (cfm) and a filter efficiency of 100%, its CADR rating is 300 cfm. Similarly, a unit with 300 cfm airflow and 75% filter efficiency will have a CADR rating of 225 cfm (300*0.75).

HUANYI Instruments "Air cleaner testing (CADR testing)" related materials

Large room Air purifiers have a higher CADR rating than that of smaller air purifiers.