Wireless building automation systems are gaining momentum as they promise an easy installation in old and new buildings. But, the design of wireless building automation systems is still an extensive manual process with little to no tool support. In result, the system commissioning ends in trial-and-error set-ups to identify interoperable devices, to solve issues with wireless signal propagation and to understand energy problems of nodes. This paper introduces a holistic design approach that addresses these common issues in wireless building automation system design. It takes up novel design concepts and tools from wired system design and combines them in a holistic tool environment that supports the engineer in his common work flow to efficiently design reliable wireless building automation systems.