Informational Guide

CADR Rating for Air Purifiers Explained

CADR rating is one of the most important aspects when buying an air purifier. Our guide teaches you everything you need to know about clean air delivery rate.

by Josh M

There are various specs to consider before buying an air purifier, with the CADR rating being one of the most important.

If you’re wondering why they’re so crucial, what they mean, or have any other questions regarding CADR ratings, then you’re in the right place. Our guide will take you through everything you need to know!

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Invented by the Association of Home Appliance Manufacturers (AHAM), the Clean Air Delivery Rate (CADR) rating measures how effective an air purifier is. Air purifiers aren’t a “one-size-fits-all,” so it’s important to pay attention to this.

CADR metrics consist of 3 different category performances: dust (0.5 – 3 microns), smoke (0.09 – 1 micron), and pollen (5 – 11 microns). In each one, the rating measures the amount of cubic feet of air that the air purifier model in question removes each category of particle per minute. The higher the CADR score is in that category, the more efficient it is at removing particles of that size.

Reasons to pay Attention to CADR

Why does CADR rating matter? Well, for starters, they can help make it easier to decide between certain models of air purifiers. Imagine that you’re trying to pick between 2 that cost the same, but one has a significantly higher rating. You’ll be getting more bang for your buck with that one!

The CADR offers a very specific measurement of how your purifier will filter out certain particles. If you’re looking to buy a purifier because you have pollen allergies, but the purifier you have your eye on can’t filter out particles the size of pollen, then it won’t be of much help to you.

If you are just looking for the cleanest air possible, then you want a high CADR rating. Measuring both filter efficiency and airflow, it will give you a clear picture as to how well it will remove contaminants from your home.

How CADR for Air Purifiers is Measured

Determined by an ANSI/AHAM AC-1 test, it’s completely standardized. They place the air purifier unit to be tested in a chamber measuring 1008 ft3, representing a 12×12 room with a 7-foot-high ceiling. Once they have it running at full speed for 20 minutes, they measure the quantity of the 3 types of pollutants we mentioned (smoke, pollen, dust) and how quickly the purifier can remove them.

This test is incredibly accurate and applicable to residential air purifiers, which involve the following limitations:

  • Maximum Smoke CADR Rating of 450 CFM 
  • Maximum Pollen CADR Rating of 450 CFM 
  • Maximum Dust CADR Rating of 400 CFM

What is Considered a Good CADR Rating for Air Purifiers?

Typically, anything rated above 310 CFM is going to be a higher quality model, though the higher the rating, the better it’ll be. To receive an Energy Star rating, you’ll need to look at the dust CADR rating. It should have a rating of at least twice the power on the highest fan speed. For example, if the purifier model draws 100 watts on high, it should have a dust CADR of at least 200.

Those with high CADR ratings involve a high fan power in order to serve a larger room/space. However, a low rating doesn’t always indicate that it’s an inferior machine. It’s possible that a higher-quality purifier has a lower CADR rating but uses a higher quality filtration system!

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CADR Rating Scale: Air Purifier Brand Comparison

Dyson Air Purifiers CADR Rating

With the vast majority of Dyson air purifiers, you’re not even going to get a CADR rating, as they simply don’t quote any CADR score for their products. So, just don’t even waste your time trying to look for them with Dyson!

Honeywell Air Purifiers CADR Rating

Honeywell ranges anywhere from 100 to 320, depending on the model and the pollutant type. You can see that they are all pretty efficient, though they are designed for different purposes and sizes of spaces/rooms.

For example, the Honeywell HPA300 is ideal for rooms of 465 square feet and has a rating of 320 dust, 300 overall. This is their most popular product, and you can see why when looking at the CADR.

Winix c535 CADR Rating

The c535 is definitely the most popular model from Winix, and features a CADR rating of 243 Dust, 232 Smoke, and 246 Pollen. This is a very high rating, especially from such an affordable brand!

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People Also Ask (FAQ)

Is a higher CADR better?

Generally speaking, yes. The higher the CADR rating scale, the more effective the CADR air purifier is at cleaning indoor air.

What does “AHAM verified CADR” mean?

The American Household Appliance Manufacturers (AHAM) represents all manufacturers in home appliances. If their CADR rating is verified, you know that it’s a real and reputable rating that they have to legally approve of.

Is CADR the same as CFM?

It’s similar, though not the same. CADR does measure the airflow (CFM) times the efficiency of the air filter. For example, if an air filter sports 200 cfm and 100% efficiency, the CADR of that model would be 200.

Is it good to sleep with an air purifier on?

It’s great, in fact! While you’re sleeping, the air purifier will take care of impurities in the air, reducing odors, irritations, and more.

How accurate are CADR ratings?

They’ve proven time after time to be incredibly accurate. This is because of the very controlled testing environment with not much room for variation.


Now that you’re practically an expert in CADR ratings and what they mean for air purifiers, are you ready to go ahead and pick one out for yourself and your home? We hope that our guide was able to help you out and that you feel confident in selecting a model just right for you.

Last Updated on July 16, 2021

Josh M

My name is Josh and I am obsessed with the HVAC industry. I created this website to help HVAC techs of all levels get the best out of their heating & cooling systems. I have spent thousands of hours studying air conditioners, heaters and home air products so you can learn & buy with confidence. Learn more about the team here.