Further improvements in the energy performance of buildings and equipment are important to Europe as measures to reduce energy demand as well as greenhouse gas emissions. For both the residential sector and the service sector, energy needed for heating and ventilation, as well as air conditioning represents the largest share of all energy needs in these sectors, and there are large potentials for further improvements in the energy performance in the climate envelope of most European houses and buildings. The International Institute for Applied System Analysis has developed the Integrated Assessment Model GAINS. The GAINS models' most recent methodology updates allow for a detailed description of the residential and commercial sector with energy use, potential for energy demand reduction as well as energy demand reduction costs. To implement the new detailed methodology for the European version of the GAINS model, a data inventory is needed. In this study, detailed data on energy use, building stocks and control technologies have been compiled and converted into the format suitable for the GAINS model. Bottom-up projections have been calibrated with the EU energy projections currently used as a European baseline in the GAINS model for the EU-27 countries as well as Norway, Switzerland and Turkey.