So what exactly is CADR rating and what are the highest possible ratings awarded to home air cleaners?
The Association of Home Appliance Manufacturers (AHAM) has developed a method for measuring an air purifier’s performance called Clean Air Delivery Rate (CADR), to provide consumers with a metric to compare different models of air purifiers.
CADR is the volume of filtered air produced by an air cleaner, measured in cubic feet per minute (CFM).
CADR takes into account an air cleaner’s ability to remove only particulate air pollutants completely disregarding gaseous pollutants.
We discuss health-related dangers posed by both particulate pollutants and gaseous pollutants elsewhere on this site.
We also emphasize how important it is for a home air cleaner to have the capacity to filter out the most dangerous types of air pollutants – gases & odors.
The fact that the CADR rating measures the filtration of only particles, and completely disregards gases & odors such as volatile organic compounds (VOCs), drastically reduces its real value to potential buyers – especially those ones who are seeking to purchase an air cleaner to control a health condition.
The particles measured by CADR are dust, pollen and tobacco smoke 0.1 to 11 micron in size. The maximum CADR ratings awarded by this system will be 450 for pollen and tobacco smoke and 400 for dust.
The rule of thumb is the higher the CADR rating, the better.
Let’s repeat it once again: you cannot use the CADR metric to compare home air cleaners which remove both particles and gaseous pollutants at the same time – CADR is only capable of testing particulate pollution filtration.
It is almost certain that this rating will not help allergy sufferers to make the right buying decision.
This system has been recognized by US government bodies such as the Environmental Protection Agency (EPA) and the Federal Trade Commission (FTC).
However, it has been widely criticized by experts and consumers alike.
For a number of different reasons.
- AHAM excludes the removal of gaseous pollutants and odors from their tests.
We know the dangers posed to human health by gaseous pollutants. While ignoring this parameter the CADR does not really help identify the highest-quality home air purifiers which attempt to deal with this type of contaminant.
- AHAM’s tests exclude particles smaller than 0.1 microns in size. We know that the smaller the particles, the bigger the damage to the body. Exclusion of smaller particles works against higher-quality home air cleaners which attempt to deal with this issue.
- AHAM’s tests are very short. The CADR system disadvantages the long-term performance of high quality air cleaners by emphasizing the short-term results instead. AHAM’s tests last for only 72 hours which is not enough to assess the real long-term value of an air cleaner.
Highest CADR Ratings
Indeed, many manufacturers of excellent, medical grade home air purifiers have not signed up with the CADR system.
For example, manufacturers of IQAir air purifiers (considered to be the best ones on the market) have decided against using the clean air delivery rate metric for their models.
On the other hand, excellent Blueair air purifiers do use CADRs for their machines.
The highest possible CADR ratings are:
Blueair air purifier
- Tobacco Smoke = > 450
- Pollen = > 450
- Dust = > 400
One of Blueair’s best models Blueair 650E enjoys the highest possible CADR rating.
But Blueair have achieved this by having a major compromise in their design – lack of a pre-filter that most premium air purifiers have.
Other air purifiers with highest CADR ratings (as of January 2010) are:
- Airgle 750
- Nano Biothys NBA 750E
- Riccar RZAP-C
- Riccar RZAP-O
- Simplicity Riccar SZAP-C
- Simplicity Riccar SZAP-O
- Winix AF-200J
- Winix AF-205J
These and other clean air delivery rate measurements can be retrieved from AHAM’s website.
In general, our advice for consumers is to use CADR as a rough guide when choosing a pure-particle-filtration air cleaner.
If you want to learn more about different types of air purification technology and how to choose the best home air cleaner for your own needs, please visit this article.
What Do YOU Think About CADR Rating?
So what is “your” opinion about CADR?
Do you think it is an adequate measure for comparing different types of air cleaners?
Did you find it useful in choosing your own air cleaner?
Please share your thoughts and opinions below.