A window ventilator is a passive air inlet integrated on top of the window frame, on glass or intermediate rail that facilitates controlled natural ventilation driven by wind-induced pressure differences and thermal buoyancy effects.

Depending on the design, window ventilators may incorporate self-regulating elements, like a self-regulating damper so ensure a maximum flowrate as the wind speed increases.

The airflow rate (at 1 Pa) varies from 7 to 80 m³/h.m