What Is Clean Air Delivery Rate (CADR)?

How well an air purifier works depends on the efficiency of the unit itself (the percentage of pollutant removed as it goes through the unit) and the amount of air handled by the device.

For example, a filter may remove 98% of the pollutant in the air that passes through it, but if the airflow rate is only 20 cubic feet per minute (CFM) it will take a very long time to process the air in a typical room of 1,000 cubic feet.

Put another way, an air purifier must have the proper capacity to handle the volume of air in the room where it operates in addition to being able to filter very small particles. In other words, while filtration efficiency is important, it is the amount of times that the air in the room is scrubbed by moving it through the filter that really counts.

For example, let's say that your hands are covered with greasy, oily soil. You apply soap but only rub them together one time. Your hands don't get very clean, do they? But if you rub your hands together over and over the greasy dirt is soon rinsed away. This is exactly why Blueair's combination of high efficiency filtration and air volume results in an air purifier that produces the most clean air in its room size category!

Air purifiers are tested measuring their ability to remove airborne pollutants such as tobacco smoke, dust and pollen. The results are measured in what is known as Clean Air Delivery Rate or CADR.

CADR is a measure of the number of CFM of air an air purifier cleans of a specific material. For example, if an air cleaner has a CADR of 380 for tobacco smoke particles, (As the Blueair 501 does), it will reduce smoke particle levels to the same concentration as would be achieved by adding 380 cubic feet of 100% clean air every minute!

Put another way, the Blueair 501 with a CADR of 380 for smoke particles will clean the air in a typical 10 x 12 room with eight foot ceilings (960 cubic feet) every two and a half minutes! And, because the Blueair 501 has the highest CADR of any unit tested in its room size capacity, you can be assured of getting the most clean air for your money!

The Blueair 501 tests at a CADR of 380 for smoke, 390 for dust and 390 for pollen making it the very best performing air purifier available.

To simplify CADR, more is better! And nobody produces more clean air in our room size category than Blueair! AHAM recommends the Blueair 501 for rooms up to 550 square feet (22 x 25 assuming an 8' ceiling).