The energy refurbishment of the existing building heritage is one of the pillars of Italian energy policy. Aiming for energy efficiency and energy saving in end uses, there are wide and diversified improvement strategies, which include interventions on the building envelope and Heating, Ventilation, and Air Conditioning (HVAC) systems, with the introduction of renewable energy sources. The research aims at evaluating the building energy consumptions and Indoor Environmental Quality (IEQ), varying the airflow rates handled by the HVAC system. A Case Study (the Aula Magna of a university building) is analysed; an in-situ monitoring campaign was carried out to evaluate the trend of some environmental parameters that are considered to be significant when varying the external airflow rates handled by the HVAC system. Additionally, dynamic simulations were carried out, with the aim of evaluating the energy savings coming from the airflow rates reduction. The results of this case study highlight the opportunity to achieve significant energy savings, with only slight variations in IEQ; a 50% reduction in airflow rate would decrease energy consumption by up to 45.2%, while increasing the carbon dioxide concentration from 545 ppm to 655 ppm, while the Particulate Matter and Total Volatile Organic Compounds increase is insignificant.

The carbon neutrality of the built environment plays a key role in fighting the climate crisis and fully realising ecological transition. In this field, the aim of the paper is to promote a new production paradigm that enables an integrated process from the design phase to the production of high-performance building components, to their “tailor-made installation” for the efficiency enhancement of the national residential building stock, reducing resource consumptions, costs, construction time and the associated environmental impact. The methodological approach is based on three key elements: digitalisation, production and performance. Recent technologies make it possible to achieve important goals, through the creation of the digital cataloguing of existing buildings, advanced dynamic simulations, improved energy performance for building stock and industrial production chain optimisation of the construction sector according to off-site construction criteria. This strategy was tested on a demonstrator building. The methodology application has made it possible to validate a catalogue of standardised insulation solutions that can be applied to 90% of the existing national building stock and that can reduce installation times by 60% and costs by around 30% compared to traditional techniques, while complying with the national requirements on thermal building insulation. The study is able to organise production according to advanced standardisation in order to meet the real demand of the market with advantages in term of production costs and economies of scale.

The control and improvement of energy-environmental quality in buildings are responsible for almost 40% of the emissions related to energy and processes, and are essential to achieve the commitment of the Paris Agreement and the Sustainable Development Goals (SDGs) United Nations (UN). This paper provides a support tool to planners and administrators of the territory for the identification of interventions aimed at the energy requalification of the existing Italian building heritage, mainly for residential use. The purpose of this tool is to reduce energy consumption by intervening on the building envelope with specific solutions that are identified through a matrix resulting from the study. In the first part of the study, an analysis was carried out on various factors such as the existing residential building, the building and construction types and the materials of the envelope typical of each construction period, which are critical for energy efficiency issues. In the second part of the study, the analysis of the state of the art of the insulating materials existing on the international and national market was carried out, in order to standardize the efficiency interventions of the building envelope. By exploiting the potential of the proposed matrix, and integrating it with Geographic Information System (GIS) technology, it would be possible to create a database containing information regarding the characteristics of the building envelope of the residential building stock and to identify a set of insulation interventions more suited to each specific case near Rome, Italy.

Enhancing energy efficiency in buildings plays a pivotal role in realizing the ambitious objective of achieving carbon neutrality by 2050, as outlined in the European Green Deal. Roofs represent the technical element most affected by energy phenomena related to heat transfer: in winter, roofing can lose up to 35% of heat, and the summer heat flux can even be higher. This paper provides a catalogue of optimized and sustainable solutions, with a specific focus on standardization and prefabrication principles, for enhancing the energy efficiency of the most prevalent types of roofs that characterize the national residential building heritage. The methodological approach that guided the research presented in this article was based on the identification and study of the most common roofings in the diverse national residential building heritage, followed by their classification according to their construction era. In the context of essential energy retrofitting of deteriorated residential building stock, 21 optimized standardized solutions have been identified. The outcome of performance evaluations of the proposed solutions allowed the implementation of a matrix that can be a valuable support for designers in selecting the most efficient precalculated and prefabricated solutions for the national residential building heritage based on energy performance and sustainability criteria.

The building and construction sector significantly impacts CO₂ emissions and atmospheric pollutants, contributing to climate change. Improving energy efficiency in buildings is essential to achieving carbon neutrality by 2050, as outlined in the European Green Deal. This study presents a decision-support tool for energy retrofit interventions in existing residential buildings. The methodological approach begins with the identification and classification of common roof and wall types in the national residential building stock, segmented by construction period, followed by defining optimized, pre-calculated standardized solutions. The performance evaluations of proposed solutions resulted in a matrix designed to guide practitioners in selecting pre-calculated, efficient, and sustainable prefabricated solutions based on energy performance criteria. The tool developed from this matrix enables preliminary energy assessment, offering an overview of potential retrofit interventions. It assists designers in identifying specific cases based on construction period, building type, and climate zone, allowing for the selection of standardized solutions, energy pre-analyses, energy and cost-saving simulations, and access to detailed performance sheets. Unlike other tools requiring extensive input on opaque envelope components and thermo-physical calculations, this tool streamlines the selection process of vertical and roof closures based on construction age and building type. Additionally, the tool estimates potential economic savings and the Net Present Value (NPV) of proposed insulation solutions, identifying available incentives for the intervention.