A method for controlling a ventilating apparatus (11) for ventilation and temperature control of accommodations, e.g. in vessels. The apparatus is connected to at least one ventilation channel (10) and comprises means for volume control of the air flow to the accommodation, means for temperature control of the air flow to the accommodation, and a control unit (13) for controlling the flow and temperature, for adaption to a desired temperature level. The control unit (13) is manipulated for reduction of temperature from a value of origin to a desired value which is at a certain distance from said value of origin. The flow controlling means and the temperature controlling means are adjusted for a rapid reduction of the temperature during a predestinated period of time. After this period of time has lapsed, these means are reset to provide a temperature level which is lower than the original value which existed before the reduction in temperature was started.