CADR. CADR takes into account air leakage, the small amount of particles the HEPA does not filter out, and how often the air purifier cleans previously cleaned air .
Another way to think about it is that a strong fan with no filter may have a high airflow number, but is not producing any clean air (CADR=0).
Also consider real-world tests:
CADR tests are done in labs, so don’t necessarily tell the performances in the real world. We recommend comparing CADR and the data from real-world tests when choosing an air purifier.
Learn more about: How to choose the best air purifier »