Method for controlling the ventilation of indoor spaces in particular for cellars

To control the ventilation of interior room spaces, and especially cellars, the vol. flow of external ambient air drawn in is set according to the functional correlation between the measured temp. and humidity or dewpoint temp. of the external air, the temp. and humidity of the internal air, and the surface temp. of the room walls, to minimize the development of condensation. A two-point control is applied through the ventilator or window opening through the measured incoming air characteristics and the internal conditions, so that the air inflow is stopped if the air dewpoint temp. falls below the air flow surface temp.