Building automation systems are widely used these days, beacause they can largely increase customers’ comfort and also can be used for decrease energy consumption. Usually one system is applied in one building and the possibility of multiple systems’ coorporation is not surveyed. This thesis is about a concrete already-built house where three systems were integrated. They are continously cooperating and distribute the buildings main functions’ control such as heating, ventillation, air-conditioning, lighting and shutter operation. After I described the three systems’ more relevant features, I will define the specified operation, show the designing process and of course I will develope the PLC’s program and the human-machine interface. However there are more systems - as I have already mentioned - this doesn’t mean they are peer, we will have to make a kind of hierarchy amongst them, where a CIB (common installation bus) based system will be in the centre. Teco a czech company develops anf manufactures this system whoch has several gateways to other bus systems making it more useful.