This paper represents the next step in the development of occupant responsive optimal control for double-skin systems that was presented at the IBPSA 2003 conference. The presented occupant responsive optimal control (Park et al, 2003b) optimizes in real-time the performance of the facade in terms of energy, daylighting, visual comfort and thermal comfort. In the aforementioned approach, the double-skin façade system was viewed as an ‘isolated’ system and hence treated as a local control problem, i.e., based purely on information about the state of the façade and its immediate environment. The paper extends the local control problem to a system control problem in which room environmental control and façade control are dealt with simultaneously. It is investigated whether the integrated control significantly outperforms the suboptimal façade control based on only local state information.