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The Air Purifier Guide

CADR Calculator for Mold Spores

Find the minimum Clean Air Delivery Rate for your room.

Mold spores (2–100 μm) are a serious indoor air quality concern, especially in basements, bathrooms, and any room with elevated humidity. A HEPA air purifier captures 99.97% of mold spores, but the key is air turnover rate — you need enough ACH to keep spore concentrations consistently low.

For mold-prone environments, we recommend 5–6 ACH instead of the standard 4.8. This higher turnover rate compensates for the continuous spore production from active mold colonies.

Important: an air purifier captures airborne spores but doesn't kill active mold. You must address the moisture source (fix leaks, run dehumidifier below 50% RH) alongside air purification for complete mold control.

ACH: 5
Minimum CADR Required
240
CFM
Room: 180 sq ft · Vol: 1,440 cu ft
Dust CADR
240
CFM
Pollen CADR
240
CFM
Smoke CADR
240
CFM
🏠 Your room, to scale (top view)
180 ft² Purifier
15 ft × 12 ft floor plan · purifier placed in a corner
Filters all the air in your room per hour — about once every 15 min.
That's roughly a 17 m² bedroom-sized space.

📐 How CADR Is Calculated

Formula: CADR = (Sq Ft × Ceiling × ACH) ÷ 60

AHAM recommends ≥ 4.8 ACH. Allergies: 6 ACH. Smoke/Asthma: 8 ACH.

Recommended Air Purifiers

Based on 240 CFM minimum Smoke CADR:

✅ Next steps
Aim for an air purifier rated at least 240 CFM (smoke CADR 216 CFM) for this room.

💡 Tips for Mold

📚 Related Guides

← Back to the main CADR Calculator