Overview of challenges of residential nearly Zero Energy Buildings (nZEB) in Southern Europe

In times of great transition of the European construction sector to energy efficient and nearly zero energy buildings (nZEBs), a market observation containing qualitative and quantitative indications should help to fill out the enormous information gaps concerning the EU 2020 carbon targets. Next to the economic challenges, there are equally important factors that hinder renovating the existing residential building stock and adding newly constructed high performance buildings. Under these circumstances this paper summarizes the findings of a cross-comparative study of the societal and technical barriers of nZEBs implementation in 7 Southern European countries. The aim of the study was to enhance the understanding and provide and overview on future challenges of residential nZEBs in Southern Europe. The result presents an overview of challenges and provides recommendations based on available empirical evidence to further lower those barriers in the European construction sector. The paper finds that the most Southern European countries are poorly prepared for nZEBs implementation and especially for existing buildings. It is essential creating a common approach to further develop nZEBs concepts and definitions in adaptation with the climatic, societal and technical state of progress in Southern Europe. The paper provides suggestions for minimum energy efficiency and renewable energy thresholds to shift the identified gaps into opportunities for future development in deep renovation of buildings.