What is the Clean Air Delivery Rate (CADR)?


Do you fall in the group of individuals who are always complaining about polluted air inside the house? Since we spend most of our time indoors, it is very important to keep our indoor air pollutant free. When our indoor air is pollutant free, it means we are also free from the danger of catching various illnesses such as asthma, breathing problems and allergies. When searching for the best air purifier in the market, most people leave out very important details that need to be taken into consideration. One of the main factors to consider is the Clean Air Delivery Rate (CADR).

What is CADR – Clean Air Delivery Rate?


CADR of an air purifier is an arithmetical value given to an air purifier based on tests performed by AHAM (Association of home appliance manufacturers). CADR also defines how well the air purifier reduces pollen, tobacco smoke and dust. This means CADR provides an even, unbiased judgment by which buyers can effortlessly gauge the efficiency of an air purifier.

Since there are so many types of air purifiers in the market, such a rating is extremely necessary. AHAM also highlights that CADR ratings are binding irrespective of particular elimination technology used. In other words, whether the air purifier uses an ionizer or HEPA filter, CADR deals only with the end result. However, CADR is useful only to portable purifiers, and not in-house air purifiers which use different methods to determine their effectiveness.

How is CADR Determined?

An air purifier is given a CADR rating through a very simple and easy to understand process. The air purifier is positioned in a room of the same size as the same room you will be trying to clean. Before the air purifier is triggered, the amount of impurities in that room is measured. Then the air purifier is activated for a short period of about twenty minutes. At this time, the amount of impurities is re-evaluated from time to time. Lastly, the reduction in impurities is associated to the natural rate of decay. When the test is over, the air purifier is given its ratings.

A stronger air purifier have CADR rate of over 400, and those rated 100 are considered as very weak, or the higher the dust, tobacco smoke and pollen ratings, the faster the air purifier filters the air than an air purifier with lower ratings.

The three main CADR ratings

There are 3 CADR ratings that are given on the AHAM seal. They represent the air purifier efficiency against the 3 common indoor air pollutants: pollen, tobacco smoke and dust.

Are CADR ratings Accurate and Useful?

CADR rating is the only key information that buyers can use to evaluate an air purifier performance. You only need to look for the AHAM seal to get all the information you need. In addition, CADR testing has a history of almost 30 years. Recognized organizations beyond air purifiers industries have embraced CADR including Federal trade commission and Environment Protection Agency. Therefore, there is no good reason to believe that CADR is not accurate or useful.

More facts about CADR

*You need to know that CADR does not measure all health hazards most people buy air purifiers to remove.

*CADR is irrelevant to organic contaminations, remember it is only checks dust, pollen and tobacco smoke. This means you need to check other factors so that you can purchase the best air purifier.

*CADR is a very short test that only lasts for 20 minutes. So, any long term shortcoming of the purifier cannot be identified. Keep in mind purifier’s efficiency declines with age.

*AHAM certification is not compulsory, and not all companies have joined. In addition, companies need to pay a fee to have their products certified. A commission on each sale of air purifier bearing the CADR seal is also extracted.

*Various quality brands especially the smaller companies have not submitted their machines to AHAM for CADR ratings.


CADR is the best tool to measure the efficiency of air purifiers. However, CADR should not be the only important factor in determining the value of an air purifier. Instead, you should check for CADR along with other element such as permanence and ability to reduce odor and gasses. Remember, CADR only checks tobacco smoke, pollen and dust. The AHAM directory is published twice every year.