
When you are going to buy a new air purifier, it is important to delve into its performance. For example, you can pay attention to the maximum surface area and the minimum size of polluted particles that can be filtered from the air.
Something you should also pay attention to is the CADR rating. If you don’t know what this means, you’ve come to the right place. I’ll tell you what CADR stands for, what it means and why it’s so important.
CADR: Cleaning Air Delivery Rate
CADR is the abbreviation for Cleaning Air Delivery Rate. It is a rating that indicates how much air an air purifier can clean in a given time frame. The CADR rating is often indicated in cubic meters per hour (m3/h).
The CADR rating is used internationally and is considered the industry standard for air purifiers. CADR was developed in the early 1980s by AHAM (Association of Home Applicance Manufacturers)1Clean Air Delivery Rate, Wikipedia.org.
The CADR rating is used internationally and is considered the industry standard for air purifiers
This is how CADR is rated
But how is CADR rated? For this, we look at how quickly the air purifier can completely clean the air in a closed space. In many cases, a laboratory or test center is used for this. After a zero measurement, the air purifier is started and the time taken by the air purifier is measured.
CADR valuation looks at three types of contaminated particles, with different minimum and maximum values2AHAM’s Air Filtration Standards, Ahamverified.org:
- Fine dust (CADR 10-400)
- Pollen (CADR 25-400)
- Smoke (CADR 10-450)
In some cases a specific CADR value is indicated for each type.

Why is the CADR valuation important?
As I mentioned in the introduction, the CADR rating is very important to pay attention to when buying a new air purifier. In many cases, the higher the CADR, the better the air purifier. But, it is actually more of an indication to know whether the air purifier suits your needs.
When you know the size of the room where you want to place an air purifier, you can use the CADR rating to calculate how long it will take to clean it. And that is precisely what is important to know for specific needs.
How many times can the air purifier clean your space?
An air purifier can clean the air at different levels. If you suffer from asthma, the air purifier will have to purify the air in the entire room several times than if you do not suffer from this. You can adhere to the following guidelines:
- Basic cleaning: the entire room twice an hour
- Allergy cleaning: the entire room 3.5 times per hour
- Asthma cleansing: the entire room 4 times per hour
So: calculate the number of cubic meters of the location where you want to place the air purifier (read more about where to place an air purifier), check the CADR rating and check whether it can clean your space enough.
References
- 1Clean Air Delivery Rate, Wikipedia.org
- 2AHAM’s Air Filtration Standards, Ahamverified.org
Tags: Air Purifier
Bram Tigchelaar
Bram is the co-founder of Purifiertester.com. Together with his brother, he gives advice for cleaner air quality in your home. He combines decades of experience in the world of air quality products with a passion for product testing. Questions about his approach? Feel free to send him a message!