Most European cities are characterized by very large areas, often formed by buildings of low quality, from a series of perspectives (architectural, technological, materials, technical systems, etc.). The possibility of renovating them is strategic to improve both the quality of life and to the possibility of economic recovery for building companies. In the last decades, the attention of the scientific community has been addressed to the energy renovation, thanks to the strong activities of the European Community in this field. However, since a relevant part of the EC territory is at risk of earthquake, the possibility to combine both energy and seismic renovation actions may be strategic for many countries. In particular, Italy and Romania are linked by a common social tradition that springs from the Roman Empire. Nowadays, this link is stronger, thanks to common interests in social, cultural and business fields. Therefore, the investigation of possible synergies for seismic and energy renovation strategies may be really interesting for both countries. In this paper, after an overview of regulations and common practices for buildings with reinforced concrete structures, in both states, some key combined renovation interventions will be described and discussed, as well as advantages and perspectives of integrated renovation approaches. The outcomes of this work are to show the way to transform existing energy-consuming and seismic-prone buildings into energy-efficient and seismic-resistant ones.

The purpose of this study was to analyze the indoor air quality, in particular, the CO₂ level, in a real environment, within 16 apartments located in the municipality of Zalău, Romania, in five recently renovated multifamily buildings in which families live under normal conditions. Long-term monitoring was undertaken for 4.5 months, during the heating season of 2022–2023. A representative microclimate perspective was analyzed: the median value of the time fraction, which exceeded the Indoor Environment Quality Category I (IEQcat I) threshold for adults’ bedrooms was 82.30%. For children’s bedrooms, it was 75.65%, while for living rooms, it was 58.78%. When considering IEQcat IV, it was identified that for the bedrooms, the time fraction for which the threshold values were exceeded was still significant (median value of 45.37% for adults’ bedrooms and 50.14% for children’s bedrooms). Even if the indoor thermal comfort conditions increased, it was found that for almost half of the time, the bedrooms did not provide a health-safe indoor environment for the occupants due to inadequate ventilation, exceeding the health threshold values. Thus, it was identified that the ventilation of buildings is a key issue within the renovation process and, currently, is not properly undertaken for the mass renovation of existing multifamily residential buildings.

The paper presents the opaque envelope system in the endowment of inhabited buildings characterized by the use of the heat of the air discharged from the inhabited spaces, circulated through the space adjacent to the living environment / outdoor environment in order to reduce the need for heat / sensitive cold of the inhabited spaces (PDE). It is presented mathematical modeling of the processes of heat transfer and flow of indoor / outdoor air circulated through parallel vertical channels. The dimensions of vertical channel opening and air flows are based on the solutions of the property transfer equations associated with Model 1 (forced laminar flow) and Model 2 (globally representative model of both laminar flow and turbulent flow). Model 2 includes both laminar flow (space heating in cold season and cooling spaces in summer season hours with sun) and turbulent flow (cooling living spaces in summer season, hours of night – free cooling). A case study and the interpretation of the results obtained regarding the energy performance of the living space in relation to similar results associated with the conventional envelope is presented.

Despite transposing the 2010/31/EU Directive’s requirements creates legal responsibilities at the national level, the nearly Zero energy building (nZEB) principle does not appear to be widely adopted just yet in many nations. Previous studies have shown that the most significant barriers include determining the cost-effective ideal integration of the technologies appropriate for nZEB and the skills constraints faced by the construction industry. In order to meet the challenge of an efficient nZEB implementation, existing certification courses and training programs are still insufficient and inadequate, and hiring experienced specialists for building retrofit and new construction is not common practice. The traditionally conservative real estate industry is nevertheless hesitant to adopt the new building standards and practices, notably in the residential sector, despite a significant movement towards nZEB and extensive energy renovation. In this specific situation, this paper provides a preliminary analysis of the European project nZEB Ready Enhancing Market Readiness for nZEB Implementation, which aims to address the issue of the effective implementation of the nZEB and make use of new possibilities to act at the market level in order to boost the market’s readiness for a successful implementation of the nZEB and to encourage demand for energy-related skills among construction workers and specialists in the countries involved and beyond.