Paci is an economist and has worked as a researcher in various fields of applied economy linked to innovation, from an industrial and development policy perspective. He is a teacher of microeconomics, macroeconomics and industrial economics at various Italian and foreign universities and for Masters and other higher education courses. Since 2008 he has held the position of Scientific Officer for the European Commission - Joint Research Centre (JRC), where he has worked on various projects regarding evaluation and studies in preparation for, and in support of, the Commission’s policies, recently also getting involved in energy policies and the evaluation of the effects of climate change. Since 2013 he has been scientific manager for projects on energy and energy efficiency in buildings, also coordinating transversal working groups in the field of energy and sustainable and innovative buildings: healthy and efficient building; building stock modelling; integration of renewable energy and energy storage solutions, construction industry innovation; social housing and fuel poverty. He is author of scientific publications and documents for the preparation, support and evaluation of legislation principles for the Commission on the matter of energy efficiency, especially with regard to the building sector (Energy Performance of Building Directive; Energy Efficiency Directive).