This chapter presents implementations of simulation-based optimization by giving two examples for finding optimum values of design/decision parameters in the building envelope, building heating/cooling systems, and energy systems. In addition, the features of the multi-objective building performance optimization program (MOBO®) are presented. MOBO is a new generic freeware able to handle single- and multi-objective optimization problems including continuous and/or discrete variables. It can be coupled to many simulation programs and has a library of different types of algorithms (evolutionary, deterministic, hybrid, exhaustive, and random). It is concluded that simulation-based optimization is an efficient method for finding optimum values ...