QuickSizing – Free Ventilation Calculator

Quick preliminary design for natural ventilation systems

Quick calculation of natural ventilation opening areas based on heat load and building height.

Units

Metric

Imperial

Heat Load

Effective Stack Height

Outside Temperature

°C

Air Outlet Temperature

°C

Discharge Coefficient – Air Inlet (C_V)

Discharge Coefficient – Air Outlet (C_V)

Assumes 1:1 ratio of aerodynamic effective air inlet and outlet area
Assumes even pressure distribution between air inlets and air outlets
Does not consider position, geometry and temperature of the heat load
Temperature difference refers to exhaust vs. supply air – not to the work-zone temperature, which requires a zonal model

Your calculated results will appear here.

Specific exhaust flow per effective exhaust area

Reference conditions: supply air 32 °C, 1:1 aerodynamically effective areas (Aa per DIN EN 12101-2), no wind, linear temperature stratification.