"Dyson has developed its own testing methodology, the POLAR test method, which, unlike the CADR, Hill said, "measures the intelligence of the purifier, the ability for it to know when that room is clean or dirty and automatically react, and its ability to mix that pure air around the room."
While Hill agrees that CADR is an important part of purification, he notes that it is important that products also sense and capture pollutants, and project air.
"I think what we're trying to do is pull back a little bit from the CADR metric," he said. "Not everyone needs an enormous CADR, has huge rooms or incredibly dirty air."
Several experts told Marketplace the CADR is the most important metric and an internationally recognized benchmark.
"CADR is what you want to know, period," said Francis (Bud) Offermann, an indoor air quality researcher who has helped develop test methods for the performance of portable air cleaners with the American Association of Home Appliance Manufacturers (AHAM).
"An air cleaner with a very high-efficient filter and very little air-flow rate will have a low CADR and little air-cleaning ability; same for an air cleaner with a very high air-flow rate and a very low filter efficiency." "