Clean Air Delivery Rate (CADR)

By Anne Fonda

A higher CADR means a system removes more allergens and pollutants, such as tobacco smoke, pollen, dust, pet dander, mold spores, airborne viruses, and more. This improves indoor air quality (IAQ) and helps everyone breathe easier.

Clean air delivery rate = (efficiency x air flow rate). According to the Environmental Protection Agency (EPA) and the Federal Trade Commission (FTC), CADR is a fair and objective measurement of air cleaner technology.

The clean air delivery rate for room air purifiers is certified by the Association of Home Appliance Manufacturers (AHAM) via third-party testing. If you are buying a room air purifier, look for the AHAM-certified CADR rating.

HVAC filters will have a MERV rating. MERV stands for Minimum Efficiency Reporting Value. It’s a rating system for air filter effectiveness that ranges from 1 to 16. The higher the number, the better the filter is at capturing the smallest particles. Performance above MERV 16 is rated as HEPA performance. MERV can affect CADR.

For HVAC air purification systems, which help filter or clean the air in your entire home, products undergo rigorous testing and use the CADR method to rate not only the efficiency with which particles are removed from filtered air but also the rate at which clean air is delivered to your living space. This is a more accurate representation of an air cleaner’s performance because it measures the end benefit to you. 

As a rule of thumb, the Association of Home Appliance Manufacturers (AHAM) recommends the CADR of an air purifier/air cleaner should be at least 2/3 of a room's size. For example, a room that is 12 ft x 20 ft has an area of 240 square feet. A good CADR for this room would be ⅔ of 240, which is 160 CFM.

While a room portable air purifier is a good solution for a dorm room or nursery, if you want the air in your entire house to be cleaner, consider a whole-house air purification system. 

The CADR rating of various filters and systems varies widely. Take a look at the table below to see the average ratings. 

American Standard has two whole-house air purification systems: the QuikBox™ Air Cleaner and the AccuClean® Whole-House Air Cleaner. The QuikBox™ has a 5” media filter with up to a MERV of 13. The AccuClean® is our top-of-the-line unit, able to capture and remove up to 99.98% of airborne particles and delivers a CADR of 1,200.

Interested in improving your indoor air quality? Contact your local American Standard dealer for product recommendations tailored to your home.

A Content Writer with Trane Technologies, Anne Fonda researches topics and writes for Trane® and associated residential HVAC brands. She works in collaboration with Trane Technologies subject matter experts, offering easy-to-understand, informative content on complex topics. Her goal is to help consumers make informed decisions on the products and services they need. 

She has written for HVAC and other service provider websites for over 16 years. Before transitioning to web content writing, Anne had a 14-year stint as an award-winning journalist. She graduated cum laude from the University of Missouri-Columbia School of Journalism. When she’s not working, Anne enjoys playing word games, reading, gardening, spending time with family, and visiting gardens and museums.

Expert review by Jennie Bergman, Senior Product Manager, Indoor Air Quality