Airflow·10 min read
Ventilation 101: CFM, Carbon Filters & Negative Pressure
Ventilation removes heat, replenishes CO₂, controls humidity and — via a carbon filter — removes odour. Undersizing it is the #1 cause of stressed plants.
Sizing Inline Fans (CFM)
Calculate tent volume (m³) and multiply by 60 for a full air exchange every minute. A 120×120×200cm tent = 2.88 m³ → ~170 m³/h minimum.
Carbon Filter Matching
Always match filter capacity to fan CFM — an undersized filter chokes the fan. When in doubt, buy the next size up: filters last longer at lower velocities.
Negative Pressure
Your extraction should slightly exceed your intake so the tent walls suck inwards. This prevents odour leaks and stops pests from being pushed out.
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