In this paper we report on the coordinated development of a regional module within a world computable general equilibrium model (CGEM) and of a bottom up energy-technology-environment model (ETEM) describing long term economic and technology choices for Switzerland to mitigate GHG emissions in accordance with Kyoto and post-Kyoto possible targets. We discuss different possible approaches for coupling the two types of models and we detail a scenario built from a combined model where the residential sector is described by the bottom-up model and the rest of the economy by the CGEM.