CADR Calculator for Allergies & Asthma
Find the minimum Clean Air Delivery Rate for your room.
For allergy and asthma sufferers, the right CADR isn't just about comfort — it's about symptom relief. Research published in the Journal of Allergy and Clinical Immunology shows that higher air turnover rates (ACH) significantly reduce airborne allergen concentrations.
The standard 4.8 ACH is the bare minimum. For noticeable allergy relief, we recommend 6 ACH. For asthma or severe allergies, 8 ACH provides the best results. This calculator defaults to 6 ACH for allergy optimization.
Key allergens and their sizes: pollen (10–100 μm), dust mite allergens (1–40 μm), pet dander (0.5–100 μm), and mold spores (2–100 μm). A True HEPA (H13) filter captures 99.97% of particles at 0.3 μm, making it effective against all of these.
📐 How CADR Is Calculated
Formula: CADR = (Sq Ft × Ceiling × ACH) ÷ 60
AHAM recommends ≥ 4.8 ACH. Allergies: 6 ACH. Smoke/Asthma: 8 ACH.
Based on 240 CFM minimum Smoke CADR:
💡 Tips for Allergies
- ✓ True HEPA (H13) is non-negotiable for allergies. Avoid "HEPA-like" or "HEPA-type" filters.
- ✓ Run the purifier 24/7 on low, not just when symptoms flare. Consistent filtration prevents buildup.
- ✓ Replace HEPA filters every 6–8 months for allergies — clogged filters lose effectiveness.
- ✓ Pair with allergen-proof bedding covers for maximum dust mite control in bedrooms.