CADR Ratings Guide For Air Purifiers

The Clean Air Delivery Rate, or CADR for short, of an air purifier is a numerical value assigned to an air purifier based on independent tests performed for the Association of Home Appliance Manufacturers (or AHAM). AHAM has been measuring the CADRs of air cleaners since the 1980s.

According to the online encyclopedia Wikipedia, the CADR definition is an indication of the volume of filtered air delivered by a portable air purifier. It goes on to say that CADR describes how well the cleaner reduces tobacco smoke, pollen and dust. In other words, the CADR is an attempt to provide a uniform, objective standard by which potential buyers can easily evaluate the effectiveness of an air cleaner.

Given the potentially bewildering variety of air purifiers available in the marketplace, such a standard is highly desirable. AHAM’s own literature on CADR also emphasizes that CADR ratings are valid “regardless of the particle removal technology utilized,” so it does not matter whether the purifier uses, for example, a HEPA filter or an ionizer. CADR measures only the end results.

Note that CADR testing is applied only to portable air purifiers, not to large whole-house purifiers, which require a different method to measure their effectiveness.

How is CADR Determined?

An air cleaner is given a CADR through a relatively easy to understand process, which is called the ANSI/AHAM AC-1 standard which measures CADR requirements:

  • The purifier is placed in a testing chamber of 1008 cubic feet.
  • Before the purifier is activated, the amount of contaminants in the room is measured.
  • The purifier is activated for a period of twenty minutes, during which time the amount of contaminants is periodically re-evaluated.
  • Finally, the reduction in contaminants is compared to their natural rate of decay.

When this test is over, testers proceed to give the unit its rating. The United States Environmental Protection Agency explains the number in the following way:

“The CADR is a measure of a portable air cleaner’s delivery of contaminant-free air, expressed in cubic feet per minute. For example, if an air cleaner has a CADR of 250 for dust particles, it may reduce dust particle levels to the same concentration as would be achieved by adding 250 cubic feet of clean air each minute.” – Environmental Protection Agency

AHAM’s Three CADR Ratings

There are three CADR ratings given on the AHAM seal. These represent the air cleaners’ effectiveness against three different common indoor air pollutants: tobacco smoke, pollen, and dust. AHAM recommends a “two thirds” rule when it comes to the first rating: “You’ll always want a unit with a tobacco smoke CADR at least 2/3 your room’s area.”

Highest Possible CADR Ratings

Due to the fact that the tests always use the same room size, there is an upper limit to meaningful CADR ratings:

  • Tobacco Smoke 10 to 450 CADR
  • Dust 10 to 400 CADR
  • Pollen 25 to 450 CADR

How Accurate and Useful are CADR Ratings?

As indicated above, CADR testing has a history of nearly 30 years, and in that time, its use has spread. Reputable organizations beyond the air purification industry have adopted CADR, including the Environmental Protection Agency, the Federal Trade Commission, and the independent watchdog organization Consumers Union.

There is no reason to believe that CADRs are not effective, within limits. Nonetheless, as always, a certain measure of caution is advisable.

Limits of CADR Ratings

The limits of CADRs are spelled out well by Ed Sherbenou, an air purifier expert who runs the website Air Purifier Power. He does not deny the usefulness of CADR ratings, but he also claims that “it’s what CADRs don’t say” that can mislead people shopping for effective purifiers.

  • Small Particle Filtration Effectiveness Not Shown – CADR numbers do not adequately inform customers of a purifier’s ability to filter out very small particles. Yet these are the most numerous, and often the most dangerous, pollutants. Looking at an air cleaner’s Clean Air Delivery Rate, you cannot tell how effective it is in dealing specifically with these tiniest bits of matter. Many air purifiers eliminate larger particles very well but are almost completely incapable of removing smaller ones from circulation.
  • Gas Filtration Not Measured – The test does absolutely nothing to measure a purifier’s ability to rid the air of gaseous pollutants, such as dangerous Volatile Organic Compounds. The three CADR numbers all refer to particulate pollution only, which is very different from gaseous pollution. Air purifiers vary wildly in their ability to deal with the latter. Because cleaning gas pollution requires different mechanisms from cleaning solid particle pollution, a purifier’s effectiveness at reducing gas is completely unrelated to its effectiveness at reducing particles.
  • Doesn’t Show Decline in Effectiveness Over Time – Because the test is so short, it does not account for the fact that some purifiers will decline in effectiveness over time.
  • Purifiers Run At Their Highest Settings – Fourth, in the ANSI/AHAM AC-1 test, purifiers are always run on their highest setting. But users will often use lower settings to reduce noise, and this can drastically reduce the efficiency of an air cleaner.

In the end, according to Sherbenou, CADR numbers are useful, but only to a certain extent:

“The cheaper the purifier, the more important the AHAM air delivery rate becomes, relative only to other units in its price class.” – Ed Sherbenou, Air Purifier Power

Though Clean Air Deliver Ratings can be found for a large number of popular brands, many of the most well-respected companies in the air purification field do not give CADRs to their purifiers. This should in no way bias potential customers against them.

Conclusion

  • CADR is one tool to measure the effectiveness of air purifiers. It should neither be ignored, nor considered the only important factor in determining the value of an air cleaner. Instead, potential customers should check for CADR numbers as one of a number of things to keep in mind, along with other factors such as long-term durability and the ability to filter out gasses and odors.
  • CADR only measures tobacco smoke, dust, and pollen
  • CADR formulas only measure the ability to remove 80% of tobacco smoke assuming one air exchange per hour
  • CADR does not measure the effectiveness of filtering the size of particles

Clean Air Delivery Rate of Air Purifiers
(Numbers Provided by AHAM)

Score ranges shown below.  A higher rating equates to a greater ability to filter that particular type of pollutant.  Please note that there are many air purifier models that are not rated by this system.

  • Tobacco Smoke 10 to 450 CADR
  • Dust 10 to 400 CADR
  • Pollen 25 to 450 CADR
ManufacturerBrandModelDust CADRTobacco Smoke CADR  Pollen CADRRoom Size (Sq Ft)Meets Ozone Limits
3M CompanyFiltreteFAP00516758104Yes
3M CompanyFiltreteFAP01867297110Yes
3M CompanyFiltreteFAP02137112153170Yes
3M CompanyFiltreteFAP02-LS137112153170Yes
3M CompanyFiltreteFAP02-LY137112153170Yes
3M CompanyFiltreteFAP02-RC137112153170Yes
3M CompanyFiltreteFAP02-RS128103149160Yes
3M CompanyFiltreteFAP03-LS306241332370Yes
3M CompanyFiltreteFAP03-LY306241332370Yes
3M CompanyFiltreteFAP03-RC306241332370Yes
3M CompanyFiltreteFAP03-RS274224312350Yes
3M CompanyFiltreteFAP04-RS-2110110128171 
Access Business GroupAtmosphere Air Purifier101076250250250390Yes
Access Business GroupAtmosphere Air Purifier102858250250250390Yes
Access Business GroupAtmosphere Air Purifier101076CH260250261390Yes
Airgle CorporationAirgleAirgle 750>400>450>450698 
Blueair, Inc.Blueair103120100110155 
Blueair, Inc.Blueair203115115115175Yes
Blueair, Inc.Blueair303145145145225 
Blueair, Inc.Blueair403240240240370Yes
Blueair, Inc.Blueair503375375375580Yes
Blueair, Inc.Blueair603>400415>450640Yes
Blueair, Inc.Blueair215B115115115175Yes
Blueair, Inc.Blueair270E135135135210Yes
Blueair, Inc.Blueair450E240240240370Yes
Blueair, Inc.Blueair455EB240240240370Yes
Blueair, Inc.Blueair510B377388378620Yes
Blueair, Inc.Blueair550E390390390605Yes
Blueair, Inc.Blueair555EB390390390605Yes
Blueair, Inc.Blueair610B>400380>450590Yes
Blueair, Inc.Blueair650E>400>450>450698Yes
Blueair, Inc.BlueairECO10195190200298Yes
Blueair, Inc.BlueairMD Pro240240240370Yes
BrookstonePure Ion Pro630285234188347292Yes
Chung Pung Co. LtdMuguCAP-G4018425394434610 
Daikin ACDaikinMC75KSU200172210267Yes
Electrolux Home Care Products NAElectroluxEL490A212210229326 
Electrolux Home Care Products NAElectroluxEL491A212210229326 
Electrolux Home Care Products NAElectroluxEL500A262261253405 
Electrolux Home Care Products NAElectroluxEL500AX262261253405 
Electrolux Home Care Products NAElectroluxEL500AZ262261253405 
GE Consumer & IndustrialGeneral ElectricAFHC08AM11088122136 
GE Consumer & IndustrialGeneral ElectricAFHC09AM11088122136 
GE Consumer & IndustrialGeneral ElectricAFHC21AM229212239329 
GE Consumer & IndustrialGeneral ElectricAFHC23AM229212239329 
GE Consumer & IndustrialGeneral ElectricAFHC32AM335322325499 
GE Consumer & IndustrialGeneral ElectricAFHC33AM335322325499 
Gree Electric Appliances, Inc.GreeGCF280CANA160140180220 
Gree Electric Appliances, Inc.SoleusairAH1-CC-01160140180220 
Haier AmericaHaierHAPE200202130249201 
Haier AmericaHaierHAPE300233170232264 
Haier AmericaHaierHAPM10010269119107 
Headwaters Inc.Brookstone561274225176237273Yes
Headwaters Inc.FilterStreamA550225176237273Yes
Headwaters Inc.FilterStreamA600257160256248 
Headwaters Inc.FilterStreamA700285260275403 
Headwaters Inc.FilterStreamA710285260275403 
HoMedics, Inc.HoMedicsAR-10917599116 
HoMedics, Inc.HoMedicsAR-20126117123181 
Kaz, Inc.Honeywell10590919191140Yes
Kaz, Inc.Honeywell1620044535880Yes
Kaz, Inc.Honeywell17000130130130200Yes
Kaz, Inc.Honeywell17005130130130200Yes
Kaz, Inc.Honeywell18155132127135197Yes
Kaz, Inc.Honeywell50100100100100150Yes
Kaz, Inc.Honeywell50101100100100150Yes
Kaz, Inc.Honeywell50150150150150235Yes
Kaz, Inc.Honeywell50200200200200304Yes
Kaz, Inc.Honeywell50250250250250390Yes
Kaz, Inc.Honeywell16200C44535880Yes
Kaz, Inc.Honeywell17000-N130130130200Yes
Kaz, Inc.Honeywell17000-S130130130200Yes
Kaz, Inc.Honeywell17000-TGT130130130200Yes
Kaz, Inc.Honeywell17005-N130130130200Yes
Kaz, Inc.Honeywell17007-HD130130130200Yes
Kaz, Inc.Honeywell50100-N100100100150Yes
Kaz, Inc.Honeywell50150-N150150150235Yes
Kaz, Inc.Honeywell50200-N200200200304Yes
Kaz, Inc.Honeywell50250-N250250250390Yes
Kaz, Inc.Honeywell50250-S250250250390Yes
Kaz, Inc.Honeywell50255-HD250250250390Yes
Kaz, Inc.HoneywellHAW-50136244737Yes
Kaz, Inc.HoneywellHFD-01035405562Yes
Kaz, Inc.HoneywellHFD-010C35405562Yes
Kaz, Inc.HoneywellHFD-01535405562Yes
Kaz, Inc.HoneywellHFD-015C35405562Yes
Kaz, Inc.HoneywellHFD-110698088124Yes
Kaz, Inc.HoneywellHFD-110C698088124Yes
Kaz, Inc.HoneywellHFD-112698088124Yes
Kaz, Inc.HoneywellHFD-116C698088124Yes
Kaz, Inc.HoneywellHFD-120-Q100110132170Yes
Kaz, Inc.HoneywellHFD-120QC100110132170Yes
Kaz, Inc.HoneywellHFD-122C100110132170Yes
Kaz, Inc.HoneywellHFD-122-TGT100110132170Yes
Kaz, Inc.HoneywellHFD-123-HD100110132170Yes
Kaz, Inc.HoneywellHFD-130100110130169Yes
Kaz, Inc.HoneywellHFD-130C100110130169Yes
Kaz, Inc.HoneywellHFD-135989898150Yes
Kaz, Inc.HoneywellHFD-137989898150Yes
Kaz, Inc.HoneywellHFD-139989898150Yes
Kaz, Inc.HoneywellHHT-01155556585Yes
Kaz, Inc.HoneywellHHT-011C55556585Yes
Kaz, Inc.HoneywellHHT-01355556585Yes
Kaz, Inc.HoneywellHHT-013-HD55556585Yes
Kaz, Inc.HoneywellHHT-016-MP55556585Yes
Kaz, Inc.HoneywellHHT-05568498076Yes
Kaz, Inc.HoneywellHHT-057C67456470Yes
Kaz, Inc.HoneywellHHT-0809011090170Yes
Kaz, Inc.HoneywellHHT-080C9011090170Yes
Kaz, Inc.HoneywellHHT-0819011090170Yes
Kaz, Inc.HoneywellHHT-081C9011090170Yes
Kaz, Inc.HoneywellHHT-082-TGT9011090170Yes
Kaz, Inc.HoneywellHHT-085-HD9011090170Yes
Kaz, Inc.HoneywellHHT-0909011090170Yes
Kaz, Inc.HoneywellHHT-090C9011090170Yes
Kaz, Inc.HoneywellHHT-145120120130185Yes
Kaz, Inc.HoneywellHHT-145-TGT120120130185Yes
Kaz, Inc.HoneywellHHT-149120120130185Yes
Kaz, Inc.HoneywellHHT-149C-CST120120130185Yes
Kaz, Inc.HoneywellHHT-149-HD120120130185Yes
Kaz, Inc.HoneywellHHT-155146118148182Yes
Kaz, Inc.HoneywellHHT-155-SMS146118148182Yes
Kaz, Inc.HoneywellHHT-157C139120151185Yes
Kaz, Inc.HoneywellHHT-217547895120Yes
Kaz, Inc.HoneywellHHT-219547895120Yes
Kaz, Inc.HoneywellHHT-219C547895120Yes
Kaz, Inc.HoneywellHPA-05055526080Yes
Kaz, Inc.HoneywellHPA-050-TGT55526080Yes
Kaz, Inc.HoneywellHPA-051C64455770Yes
Kaz, Inc.HoneywellHPA-150125110130177Yes
Kaz, Inc.HoneywellHPA-150-TGT125110130177Yes
Kaz, Inc.HoneywellHPA-151C134120151185Yes
Kaz, Inc.HoneywellHTT-02254636299Yes
Kaz, Inc.VicksV907144535880Yes
Kaz, Inc.VicksV9071C44535880Yes
Master Brands Group CorporationWhirlpoolAP25030K215205224320 
Master Brands Group CorporationWhirlpoolAP45030K328315354490 
Master Brands Group CorporationWhirlpoolAP51030K325315401490 
Master Brands Group CorporationWhirlpoolAPR25130L198191214296 
Master Brands Group CorporationWhirlpoolAPR25530L198191214296 
Nano Biothys Company, LTD.Nano BiothysNBA750A>400>450>450698 
Nano Biothys Company, LTD.ZalmandnNBA700A425394434610 
Rexair LLCAquaRainbowE261556790 
Rexair LLCKingNeptuneE261556790 
Rexair LLCRainbowE261556790 
RiccarRiccarRAPL182183194284 
RiccarRiccarRAPM126117138180 
RiccarSimplicityHHPL182183194284 
RiccarSimplicityHHPM126117138180 
Sears, Roebuck and CompanyKenmore851509898103150 
Sears, Roebuck and CompanyKenmore85264330300380465Yes
Sears, Roebuck and CompanyKenmore85300197197214300 
Sears, Roebuck and CompanyKenmore85450298291343450 
Sears, Roebuck and CompanyKenmore85500182183194284 
Sears, Roebuck and CompanyKenmore85501142138145213 
Sears, Roebuck and CompanyKenmore857778997110151Yes
Sharp Electronics CorporationSharpFP-A40C140129160200 
Sharp Electronics CorporationSharpFP-A40U140129160200 
Sharp Electronics CorporationSharpFP-P30U9280130124 
Sharp Electronics CorporationSharpFP-P35CX150147155228Yes
Sharp Electronics CorporationSharpFP-P40CX157163156253Yes
Sharp Electronics CorporationSharpKC-830U9280130124 
Sharp Electronics CorporationSharpKC-850U164164174254Yes
Sharp Electronics CorporationSharpKC-860U231220245341 
Winix, Inc.Winix5300248235251350Yes
Winix, Inc.Winix5500248235251350Yes
Winix, Inc.Winix9300142138145213 
Winix, Inc.Winix9500182183194284 
Winix, Inc.WinixWAC 5000B184175197270 
Winix, Inc.WinixWAC-9000182183194284 
Winix, Inc.WinixWAC-9000S142138145213 
Woongjin Coway Co., LTDCowayAP-0509DH11284109130 
Woongjin Coway Co., LTDCowayAP-1005AH168154178239 
Woongjin Coway Co., LTDCowayAP-1008CH175155193240 
Woongjin Coway Co., LTDCowayAP-1008DH172145221224 
Woongjin Coway Co., LTDCowayAP-1009CH182149203230 
Woongjin Coway Co., LTDCowayAP-1503CHE226214283332 
Woongjin Coway Co., LTDCowayAP-2505CH>400402>450623 
Woongjin Coway Co., LTDCowayAP-3008FH>400>450>450698 
Woongjin Coway Co., LTDIdylisIAP-10-100113100110155 
Woongjin Coway Co., LTDIdylisIAP-10-100 C113100110155 
Woongjin Coway Co., LTDIdylisIAP-10-125136125134194 
Woongjin Coway Co., LTDIdylisIAP-10-125 C136125134194 
Woongjin Coway Co., LTDIdylisIAP-10-150165150170233 
Woongjin Coway Co., LTDIdylisIAP-10-150 C165150170233 
Woongjin Coway Co., LTDIdylisIAP-10-200178170215264 
Woongjin Coway Co., LTDIdylisIAP-10-200 C178170215264 
Woongjin Coway Co., LTDIdylisIAP-10-280290280285434 
Woongjin Coway Co., LTDIdylisIAP-10-280 C290280285434 

Further information on the Clean Air Delivery Rate can be found at http://www.cadr.org  Air Purifier Guide neither endorses nor dismisses these ratings.

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