This report is the first report of the ‘Energy Savings 2030’-project which seeks to help the Coalition for Energy Savings to produce a robust and timely input to the 2030 policy discussion. It brings together and summarises recent empirical evidence on costs and benefits of energy efficiency measures. The evidence gap in terms of reliable ex-post data is well known. In the majority of cases results from ex-ante modelling studies inform the debate. The research carried out for this report confirms the persistent gap in publicly available ex-post evaluations of energy efficiency programmes. In the household/buildings sector robust evaluations are available for the KfW energy efficiency programmes in Germany and to a certain extent for the ‘EnergieSchweiz’ programme in Switzerland and the Home Energy Scheme in Ireland. For the industrial sector evaluations have been carried out for energy efficiency programmes in the Scandinavian countries and Ireland. Given the time and resources available for this report, it was outside the scope to review these studies in detail with respect to their assumptions and methodologies used. The results reported here reflect the results and conclusions drawn by the authors. The report is structured as follows. After a short discussion of key terms and concepts, section 3 presents the empirical evidence reported in ex-post evaluations for the residential/buildings sector, the industrial sector, transport sector and energy infrastructures well as cross-sectoral results. Section 4 points to the opportunities of export markets for European energy efficiency technologies. The report concludes by comparing costs and benefits.