Is CADR a reliable measurement for comparison?

CADR stands for Clean Air Delivery Rate. Essentially, it is a metric created by the Association of Home Appliance Manufacturers (AHAM) to help consumers make comparisons between various brands and models. As can be seen in the picture below, the CADR certification comes with four numbers for comparison: the coverage area and dust, tobacco smoke, and pollen CADR ratings.

In this example, the 80 CADR rating means that it can filter out 80 cubic feet per minute (CFM) of the various air contaminants. The higher the number, the faster the air purifier will be able to clean the air.

At first glance, this system of rating air purifiers seems simple and to the point: it gives you a recommended room size as well as an idea of the filtration capabilities of the air purifier. However, the simplicity of the calculations behind the rating is a point of contention.

When calculating the CADR rating for an air purifier, the product is placed in an 11’ by 11’ room with an 8’ high ceiling – a small room by any standard. The room is completely enclosed, and the test for pollen is completed with 10 minutes, and the dust and tobacco smoke tests are completed within 20 minutes.

Due to the fact that the tests are conducted in a small, enclosed room within a short period of time, the CADR rating tends to favor air purifiers that can move air quickly. While the efficiency of the filter also comes into play, any air purifier with a low filtration rate but high airflow rate to circulate the air more quickly will have higher ratings. On the other hand, air purifiers with highly efficient filters that trap much more particulate matter but have a lower airflow rate do not fare so well.

Many manufacturers are fully aware of this flaw in the CADR rating test, so they purposefully design their products to maximize the airflow rate. We at Go-Clair do not believe in this philosophy. We believe that higher filtration efficiency should take precedence over a higher airflow rate – and we are not the only ones. There are prominent air purifier manufacturers that, like us, decided not to opt for a CADR rating with AHAM.

We believe the air that you breathe should be the cleanest air possible.

Clair air purifiers. Clean air. All day. Every day.