An overall objective of our work is to improve building and systems performances in terms of durability, comfort and economics. In order to predict, improve and meet a certain set of performance requirements related to the indoor climate of buildings, the associated energy demand, the heating, venting and air conditioning systems and the durability of the building and its interior, simulation tools are indispensable. In the field of heat, air and moisture transport in building and systems, much progress on the modeling and simulation tools has been established. However, the use of these tools in an integrated building simulation environment is still limited. Also a lot of modeling work has been done for energy related building systems, such as solar systems, heat pump systems and heat storage systems. Often, these models focus on the systems and not on the coupled problem of building and systems. This thesis presents the development and evaluation of an integrated heat, air and moisture simulation environment for modeling and simulating dynamic heat, air and moisture processes in buildings and systems. All models are implemented in the computational software package MatLab with the use of SimuLink and Comsol. The main advantages of this approach are: First, the simulation environment is promising in solving both time and spatial related multi-scale problems. Second, the simulation environment facilitates flexible linking of models. Third, the environment is transparent, so the implementation of models is relatively easy. It offers a way to further improve the usage and exchange of already developed models of involved parties. More than 25 different heat, air and moisture related models are included in this work. Most of the models are successfully verified (by analytical solutions or by comparison with other simulation results) and/or validated (by experimental data). The use of the simulation environment regarding design problems is demonstrated with case studies. Overall is concluded that the simulation environment is capable of solving a large range of integrated heat, air and moisture problems. Furthermore, it is promising in solving current modeling problems caused by either the difference in time constants between heating venting and air conditioning components and the building response or problems caused by the lack of building simulation tools that include 2D and 3D detail simulation capabilities. The case studies presented in this thesis show that the simulation environment can be a very useful tool for solving performance-based design problems
