What is a good CADR rating?

A good CADR is one that matches your room: roughly 2/3 of your room's square footage in CFM. For a 200 sq ft bedroom, that's 135+ CFM; for a 300 sq ft living room, 200+ CFM. Anything above your room's requirement is a bonus that buys quieter operation. Comparing two units for the same room, the higher CADR cleans faster.

What's the difference between smoke, dust, and pollen CADR?

They're measured with different particle sizes: smoke CADR uses the smallest particles (0.1-1 micron), dust uses medium, pollen uses large. Smoke CADR is almost always the lowest number, and it's the one to compare — if a unit handles smoke particles, it handles everything bigger. Many brands only advertise the highest (pollen) number, which is misleading.

Is a higher CADR always better?

Higher CADR means faster cleaning and more headroom — you can run a larger unit on low, quietly. The downsides of oversizing: higher purchase price, bigger footprint, and higher filter costs. A unit sized 1-1.5x your room's need is the sweet spot. More than 2x is usually wasted money unless you want ultra-fast clearing after smoke or cooking events.

Does CADR include carbon filter performance?

No. CADR measures particle removal only — smoke, dust, pollen. It says nothing about VOC or odor removal, which is the carbon layer's job. This is why two units with identical CADR can perform very differently on cooking smells or paint fumes. Always check both: CADR for particles, carbon weight for odors.

Can I trust the CADR number a brand advertises?

Mostly, if it's AHAM-verified. AHAM (the industry body) independently tests and certifies CADR, and certified units carry a 'CADR verified' mark. Be skeptical of brands that list CADR without AHAM verification, or that advertise only the pollen number. For units with verified ratings, the number is real — just make sure you compare the smoke number.

CADR Rating Explained: What It Means and Why It Matters

Every air purifier spec sheet has a CADR number, and almost nobody knows what it means. Here’s the plain-English version: what it measures, why the three numbers differ, and how to use it so you stop overpaying — or under-buying.

🧰 Interactive Tools

🧮CADR CalculatorWhat CADR does your room need?→ 📏Room Size CalculatorMatch any unit to any room→

What CADR Actually Means

CADR = Clean Air Delivery Rate, measured in cubic feet per minute (CFM). It answers one question: how fast can this machine deliver clean air?

The number comes from AHAM (the Association of Home Appliance Manufacturers), which tests units in a standardized chamber and measures how quickly they remove particles. An AHAM-verified CADR is one of the few spec-sheet numbers you can genuinely trust.

Why There Are Three Numbers

Every certified unit lists three CADR values:

CADR type	Particle size	Typical value
Smoke	Smallest (0.1-1 µm)	Lowest
Dust	Medium	Middle
Pollen	Largest	Highest

The trick: brands advertise the pollen number. It’s the biggest and most impressive — but it’s also the least relevant. Smoke CADR tests the hardest case (smallest particles), so it’s the honest number to compare. A unit that handles smoke particles handles everything bigger.

Rule: compare smoke CADR, ignore pollen CADR.

How to Use CADR When Buying

Step 1: Find your room’s requirement

Minimum CADR (CFM) = Room area (sq ft) × 2/3

Room	Min CADR needed
150 sq ft bedroom	100 CFM
200 sq ft bedroom	135 CFM
300 sq ft living room	200 CFM
500 sq ft open plan	333 CFM

Step 2: Compare smoke CADR, not price or “ratings”

A $200 unit with 230 CFM smoke CADR beats a $400 unit with 180 CFM for the same room — for particle removal. The $400 unit might win on features, silence, or carbon, but not on raw cleaning speed.

Step 3: Remember what CADR doesn’t cover

CADR = particles only. Odors and VOCs are the carbon layer’s job, and carbon isn’t in the CADR number. For cooking smells, paint fumes, or cigarette smoke, check carbon weight separately.

Units by CADR Class (Smoke Numbers)

Class	Smoke CADR	Example units	Best for
Small	100-160	Coway Airmega 150 (160), Levoit Vital 200S (200)	Bedrooms, nurseries
Medium	200-260	Coway AP-1512HH (233), Winix 5500-2 (232), Levoit Core 400S (250)	Living rooms, master bedrooms
Large	300-400	Levoit Core 600S (400), Blueair Blue Pure 211+ (350), Coway Airmega 400 (350)	Open plans, big living areas
Extra-large	400+	Medify MA-112 (490)	700+ sq ft, basements

The Bottom Line

CADR is the single most useful number on an air purifier spec sheet — if you compare the smoke number against your room size. Ignore advertised pollen numbers, remember that CADR says nothing about odor removal, and use the area × 2/3 rule. Match the smoke CADR to your room and you’ve eliminated the #1 reason purifiers disappoint.