Multi domain modelling provides great opportunities for possible synergy between the building simulation domain and other scientific and technological domains. Although domains may have quite different models, they often use common mathematical representations, based on differential algebraic equations (DAEs) and/or ordinary differential equations (ODEs). This paper reviews the use of S-Functions in SimuLink for DAEs and ODEs modelling regarding building simulation and its potential for multi domain applications. It is concluded that ODEs are directly implementable using S-Functions in SimuLink. DAEs are indirectly implementable by a manual process of integrating Dymola/Modelica models. Examples from the literature confirm the great opportunities for the combined building thermal, geothermal, electrical and grid performance simulation.