CADR Explained: How to Choose an Air Purifier That Actually Works

What is CADR? The Gold Standard of Air Cleaning

CADR (Clean Air Delivery Rate) measures how fast an air purifier removes smoke (0.1-1μm), dust (0.5-3μm), and pollen (5-11μm). Established by AHAM (Association of Home Appliance Manufacturers), it’s the ONLY industry-validated performance metric.

Key 2024 Updates:

• U.S. FTC now mandates CADR disclosure in all ads

• 23% of "HEPA" Amazon purifiers falsify CADR data (Consumer Reports test)

3 CADR Myths Debunked

Myth 1: “Higher CADR = Better”

• Truth: Oversized CADR causes turbulent airflow, re-suspending particles.

• Formula: Ideal CADR = Room Volume (ft³) ÷ 1.55

• Example: 150 sq.ft. x 8 ft ceiling = 1,200 ft³ → 775 CADR

Myth 2: “All CADR Tests Are Equal”

• Reality: AHAM tests use 1,000+ ft³ chambers with standardized pollutant levels.

• Red Flag: Brands claiming "self-tested CADR" without AHAM ID.

Myth 3: “CADR Doesn’t Matter for Allergies”

• Data: 500+ pollen CADR reduces symptoms by 61% (Mayo Clinic 2024 study).

How to Decode CADR Numbers

Pro Tip: Prioritize smoke CADR—if it handles 0.1μm particles, larger ones are easier.

4-Step CADR Shopping Checklist

1. Verify AHAM Certification

• Check AHAM website with model number (e.g., "AC-2024")

2. Match to Room Size

• CADR ≥ 2/3 of room area (e.g., 300 sq.ft. room → ≥200 CADR)

3. Balance Noise Levels

• 50 CADR/dB ratio is ideal (e.g., 300 CADR at 60dB = good)

4. Check Filter Costs

• High CADR units consume filters 2x faster

Case Study: Why a “500 CADR” Purifier Failed

• Issue: 500 CADR unit in 120 sq.ft. bedroom created vortexes

• Solution: Switched to 320 CADR model → PM2.5 reduced 89% in 15 mins

FAQ: CADR Essentials

Q: Can I use one purifier for multiple rooms?
A: No—CADR assumes single enclosed space. Doorways cut efficiency by 40-70%.

Q: Does CADR apply to gases like VOCs?
A: No—CADR only measures particles. Pair with carbon filters for chemicals.

Q: Is CADR the same as airflow (CFM)?
A: No—CFM is raw fan speed. CADR = CFM × filtration efficiency.

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