HEPA Filter — Fan & Filter Cartoon Demo
Ceiling-mounted HEPA — interactive demo

Fan & filter cartoon explainer

Why airflow is set by the fan, not the filter — and why pressure drop rises with filter loading
Fan speed 3 / 5
Filter load 0%
Airflow (Q)
720
m³/h
Face velocity
0.45
m/s
Pressure drop
250
Pa
Fan sets the flow. Filter only resists it — increasing pressure drop, never changing face velocity independently.
Model: illustrative only — values scaled for visual clarity, not engineering accuracy.
Pressure drop: ΔP ∝ v² × (1 + filter_load_factor). Airflow reduction from fan curve intersection approximated linearly.
Reference: ASHRAE Handbook — HVAC Systems and Equipment; ISO 29463 HEPA filter series.