EECCAC is an EU funded project, where twelve participants (National Energy Agencies, Manufacturers, University laboratories and Electric utilities) from eight countries gathered to identify the most suitable measures to achieve market transformation in the direction of energy efficiency of central air conditioning systems in Europe. Within the project, some energy efficiency options (EEO) have been analysed, and a summary is presented in this paper. After setting some starting points for building, climate and simulation engine, we will present the list of HVAC system EEO covered.