Intelligent controlled facades are designed to use outdoor climate as much as possible for indoor climate　 aspects:heating ,cooling　 ventilating and day-lighting .In this paper one aspect will be discussed in more deatil:cooling by natural ventilation .The efficiency of this type of cooling is demonstrated by simulation and by monitoring in real office buildings.Design tools are derived for designing the vent openings in the facade and machines require additional air conditioning ,but even then intelligent facades will help to reduce energy costs of running the air conditioning at the moment.The height of the applicaton of intelligent features in uildings is the double skin facade.A short description will be given.