In the »EcoShopping« project, research is being conducted into technologies and processes for increased energy efficiency and user comfort in commercial buildings. For this purpose, the level of occupancy and environmental parameters in a building are monitored by means of a sensor network and a mobile robot equipped with sensors. Acoustic data is used to determine the number of persons present in the building or to assist security services. Values such as temperature and air humidity serve to allow optimization of the current user comfort. On the basis of the different types of data collected, an intelligent automation unit controls the building management system with air conditioning, heating and ventilation. Regenerative energy generation, new insulating methods and energy-saving lighting systems are used in order to further reduce energy consumption. As part of the project, existing products and new technologies are being implemented and evaluated in a shopping mall in Budapest. The research results will be collated in the form of a catalog of measures for modernization of existing buildings.