CADR Rating – What It Is And Why It Matters for Air Purifier

Josh Mitchell

Written By

Josh Mitchell

Expert Reviewed By

Holly Curell

Last Updated On

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Key Takeaways

  • CADR or clean air delivery rate is measurement how effective an air purifier is. The higher the CADR the more effective the unit is at cleaning the air.
  • CADR should be 2/3 the square footage of the covered area. It can range anywhere between 100-450 CFM (or higher). 
  • You have to combine CADR with HEPA filter and activated carbon filter in order to get the best out of your air purifier.

I’m happy to come across countless people who want an air purifier to cleanse their indoor air. Unfortunately, I also know a lot of people that have no idea what to look for when shopping for an air purifier.

One of the most important things to consider when purchasing an air purifier is its clean air delivery rate, or CADR, which basically measures filtration efficiency.

If you’re wondering why it’s so crucial or what exactly it means, you’re not alone. That’s why I’ve put this guide together. It will take you through everything you need to know about clean air delivery rates!

What Does CADR Mean?

CADR stands for “clean air delivery rate. It measures how effective an air purifier is while running on a high fan speed.

Invented by the Association of Home Appliance Manufacturers (AHAM), it measures the volume of filtered air that an air purifier can deliver, in cubic feet per minute (CFM), for three different particle types: dust, pollen, and smoke.

Dust particles range in size from 0.5 to 3 microns, smoke particles range from 0.09 to 1 micron, and pollen particles range from 5 to 11 microns.

The higher the CADR score for a particular particle type, the more effective the air purifier is at removing that type of particle.

CADR It only reflects the clean air at the highest fan speed and won’t reflect the purifier’s ability on a low fan speed.

Just keep in mind that CADR ratings are based on a standardized laboratory test and may not reflect real-world conditions or individual preferences.

What Is Considered A Good CADR Rating For Air Purifiers?

I look for air purifiers rated above 310 CFM (cubic feet per minute) to ensure I’m getting a high-quality model. A higher CFM rating means the purifier can move more air, which can be useful for larger rooms or spaces. 

The Association of Home Appliance Manufacturers (AHAM) recommends a CADR of at least 100 for smoke, 100 for pollen, and 100 for dust for a 100-square-foot room.

As a rule of thumb, the CADR of your air cleaner should be equal to at least two-thirds of the room’s area. For example, a 10×12-foot room has an area of 120 sq. ft. It would be best to have an air cleaner with a smoke CADR of at least 80. For wildfire smoke, AHAM recommends a Smoke CADR equal to the size of the room in square feet.

However, while important, the CADR rating is just one factor to consider when choosing an air purifier. It’s essential to consider multiple factors, such as the type of filter used, the noise level, and the price when choosing an air purifier.

Reasons To Pay Attention To CADR

The first thing I check on an air purifier is always the CADR because it specifies how effectively it can filter out certain types of particles from the air.

If you are looking for the cleanest air possible, a high CADR rating is crucial.

Additionally, the CADR rating can help you compare different air purifier models and determine which offers better value for your money. If two air cleaners have similar features and are priced the same, but one has a significantly higher CADR rating, the higher-rated purifier will be more effective at cleaning the air.

You also need to ensure the CADR rating of an air purifier matches your specific needs. For instance, if you’re allergic to pollen, it’s important to choose an air purifier with a CADR rating that can effectively filter out particles of that size.

How CADR For Air Purifiers Is Measured

The CADR (Clean Air Delivery Rate) rating is determined by an ANSI/AHAM AC-1 test that is completely standardized. The test involves placing the air purifier unit to be tested in a chamber that measures 1008 cubic feet, which represents a 12×12 room with a 7-foot-high ceiling.

Once they have it running at full speed for 20 minutes, they expose it to specific types of pollutants, such as smoke, pollen, and dust. The amount of pollutants removed from the air in the chamber is then measured over a specific period of time.

The results are used to calculate the CADR rating for each type of pollutant. This test is incredibly accurate and applicable to residential air cleaners, 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

CADR Ratings For Popular Air Purifier Brands

Air purifier manufacturers do all they can to set themselves apart from the competition. Part of that is ensuring their purifiers have high CADR ratings. Here’s a breakdown of some of the most popular brands and their CADR ratings.

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. Some major publications claimed to have tested their range and these are the results.

Note – We haven’t tested these products and we can not be certain they have either!

Dyson Pure Cool TP04 (according to Wirecutter)

  • 202 CFM for tobacco smoke
  • 185 CFM for pollen
  • 198 CFM for dust

Dyson Pure Cool Link TP02: (according to Consumer Reports)

  • 176 CFM for tobacco smoke
  • 181 CFM for pollen
  • 168 CFM for dust

Dyson Pure Hot+Cool HP04 (according to Wirecutter)

  • 202 CFM for tobacco smoke
  • 185 CFM for pollen
  • 198 CFM for dust

Honeywell Air Purifiers CADR Rating

Honeywell ranges anywhere from 100 to 320, depending on the model and the pollutant type. Most have a true HEPA filter and 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 sq. ft. 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. It features an activated carbon filter to reduce VOCs (volatile organic compounds) and for odor removal. It has a CADR rating of:

  • 243 Dust
  • 232 Smoke
  • 246 Pollen

This is a very high rating, especially from such an affordable brand!

Levoit CADR Rating

The Levoit Core 300 and LV-PUR131S are affordable and effective air-cleaning solutions. Both models feature a true HEPA filter and activated carbon filters, which can capture particles as small as 0.3 microns in size, including smoke, pollen, dust, and other allergens.

In terms of CADR ratings, both the Core 300 and LV-PUR131S have a CADR of 135 for smoke, 140 for pollen, and 145 for dust. These ratings indicate that both models are suitable for use in small to medium-sized living spaces, up to approximately 219 square feet.

People Also Ask (FAQs)

Is A Higher CADR Better?

A higher CADR is generally better. The higher the CADR rating scale, the more effective the CADR air purifier is at cleaning indoor air. However, there are other factors to play into a purifier’s effectiveness.

What Does “AHAM Verified CADR” Mean?

AHAM-verified CADR means the CADR rating was verified by The American Household Appliance Manufacturers (AHAM). If the purifier has an AHAM CADR rating, you know that it’s a real and reputable rating.

Is CADR The Same As CFM?

The CADR and CFM are not the same. CFM stands for cubic feet per minute. 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 is good to sleep with an air purifier on. While you’re sleeping, the air purifier will take care of impurities in the air, reducing odors, irritations, and more. Some people also sleep better with the white noise it produces.

How Accurate Are CADR Ratings?

CADR ratings are incredibly accurate. This is because of the very controlled testing environment with not much room for variation.

Is Filter Efficiency More Important Than High CADR?

Filtration and CADR ratings ultimately come down to what the user needs. People with severe allergies or respiratory conditions may prioritize better filtration, while those living in areas with high pollution levels or smoke may prioritize a higher airflow rate.

Do Purifiers With High CADR Ratings Have Higher Energy Consumption?

Air purifiers with high CADR ratings tend to have higher energy consumption. They require more powerful motors and higher fan speeds to move larger volumes of air.


Now you know just about everything I know about CADR ratings. I’m confident that this guide has provided you with the information you need to select a model that will effectively clean the air in your home and improve your indoor air quality.

Now you can confidently choose the best air purifier for your home!

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Josh Mitchell


Josh Mitchell
My name is Josh and I am obsessed with home appliances. From portable AC units to heaters and air purifiers, I enjoy testing, learning and using these devices to improve the air quality inside my family home.

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