Here's my experience...p> Many air purifier companies actively market their cleaners based predominately on this rating which stands for "Clean Air Delivery Rate". It is a measure of air flow, not air purity. This is why other companies will skip this CADR Air Purifier Ratings altogether - because it does not address some technologies critical to cleaning, and purifying the air. CADR is associated with air flow alone, make its numbers, at best, Irrelevant and at worse, Misleading.
CADR Air Purifier Ratings Do Not Factor Germs, Bacteria, Mold, Mildew, Fumes, Odors, etc.
The CADR is basically only a measure of how rapidly air is circulated through a given air filtering device. While this figure is perhaps relevant for the vast majority of filtration-only devices that attempt to clean air using only one or two types of filters, it's meaningless because filtration is simply one single aspect. The fact is that the CADR number tells you nothing about how well, or even "IF", an air purifier filters germs, bacteria, viruses and other harmful biological agents nor does it assess how well the unit clears chemical fumes and odors.
The easiest way to think of it is that, even though everyone in the industry refers to their products as an air "purifier", the fact is that the overwhelming majority of competing products out there are simply air "filters" that don't use anywhere near the number of additional "purification" technologies available, e.g., UV light, TiO2, activated charcoal, negative ionization, etc.
The AHAM organization represent big companies like Honeywell and Whirlpool to 'seeemingly' make sure politicians in Washington support their agenda. (I'm sure there are some good lobby groups but I get a little leary of lobby groups and what they have done to world views of America, to the environment, let alone to consumers. I've heard a few stories about AHAM I don't like).