Energy behaviour-driven strategies for the effective renovation of the public housing stock

Energy efficiency through building renovation and urban regeneration is a major challenge both in EU and in the Italian context, where building renovation can be considered as one of the strategies to achieve city regeneration, due to the fact that the built environment is embedded in all the four categories of urban features (i.e. physical, functional, geographical, socio-economic) or subsystems influencing energy consumption and CO2 emissions, as classified by scholars investigating the multidimensional relationship between cities and energy consumption in urban planning studies. Despite the effort in promoting lower energy consumption in buildings, the visionary energy efficiency goals set at EU level are far to be met both for new and renovated buildings. The gap between expected and actual energy consumption, together with the impact of occupant behaviour on building energy use, have been increasingly studied by scholars. Occupant behaviour has been found to be crucial in actual energy consumption, accounting for as much as 50% of the variance in heating consumption. Indeed, energy savings through behavioural factors can be as high as those from technological ones, thus giving to the occupants the possibility either to reinforce the savings from energy efficiency measures, or to waste them. Building regulations on energy consumption are formulated based on building and system characteristics and they make assumptions of occupant behaviour paradigm as static and deterministic, ignoring the fact that, during the operational phase, are people who use energy, not the building as such. The overall aim of the research is to contribute promoting urban regeneration through the energy renovation of residential buildings. The goal is to show, on the one side, the relevance of the occupant behaviour, at present seldomly included in the consideration of the measures to be adopted to renovate the buildings; on the other side, the relationship among stakeholders involved in the renovation process, in order to suggest new measures to improve the effectiveness of the process. The specific aim is to assess the impact of household energy behaviour on energy-related policies and practices tailored at reducing the energy consumption and at increasing the energy efficiency of buildings. The outcomes shall support decision-makers, planners and stakeholders to design and implement energy policy instruments and strategies to regenerate the existing built environment, with a focus on the residential sector. Despite the size of the public housing stock in Italy, which account for only 3.7% of the total housing stock, due to the favourable situation of public housing providers, having an exclusive role in building management, and similar regional regulations and procedures to comply with, the public housing sector is considered as the case study for this research. When it comes to building renovation, demonstrating the relevance of including measures to tackle household energy behaviour prior in public buildings than in the other housing stock is believe to lead to a multiplier effect, also considering that about half of the total Italian housing stock consists of multi-family buildings, by far the most building typology used for public housing stock, and they urgently need to be renovated. The general approach of this research tries to combine the review of the current state of scientific literature of the thematic field with the practical application and evaluation of a case study experience. A multi-method approach to data collection is used, applying both qualitative research methods such as content analysis and surveys, and quantitative research methods such as statistical analysis, sensitivity analysis and simulation tools to assess the energy consumption-related human factor and to determine multiple scenarios to support decision-makers towards the implementation of effective strategies. Chapter 2, 3 and 5 make an extensive use of literature review as main methods to investigate energy behaviour models in all the most relevant disciplines dealing with behavioural studies, the policy frameworks, the determinants of household energy behaviour, the strategies to promote behavioural change and the main characteristics of the Italian public housing stock in terms of roles and responsibilities. Chapter 4 presents two micro-level approaches to the topic, applying, on the one side, quantitative research methods as statistical analysis on the census data, and on the other side, qualitative research method for the analysis of the questionnaires resulting from the survey. Chapter 6 applies building energy simulation to investigate the impact of behaviour and to build scenarios to inform decision-makers, while in Chapter 7 a multi-criteria decision-making tool is adopted to make evidence of the behaviour-related improvements in the framework of housing renovation strategies, and to then suggest new solutions to improve them.

L'obiettivo generale della ricerca è quello di contribuire alla promozione di processi di rigenerazione urbana attraverso il retrofit degli edifici residenziali, per mostrare da un lato, la rilevanza del comportamento degli occupanti, attualmente raramente incluso tra le misure da adottare per la riqualificazione; d'altra parte, la relazione tra gli attori coinvolti nel processo di riqualificazione, al fine di suggerire nuove misure per migliorarne l'efficacia. L'obiettivo specifico è quello di valutare l'impatto del comportamento energetico delle famiglie sulle politiche e le pratiche per ridurre i consumi energetici e aumentare l'efficienza degli edifici. I risultati sono pensati per supportare i decisori e i pianificatori a progettare e attuare strumenti e strategie per rigenerare l'ambiente costruito, con particolare attenzione al settore residenziale. Nonostante le esigue dimensioni dello stock abitativo pubblico, caratteristiche irripetibili quali la proprietà unica, la natura pubblica e le analogie tra le normative e procedure regionali, sono le ragioni alla base della scelta come caso di studio privilegiato per questa ricerca. I capitoli 2, 3 e 5 fanno ampio uso della revisione della letteratura esistente come principale metodo per studiare i modelli e le determinanti del comportamento; le strategie per incentivare un cambio di paradigma nel comportamento, secondo diversi livelli di governance; le principali caratteristiche del patrimonio abitativo pubblico italiano in termini di ruoli e responsabilità. Il capitolo 4 presenta due diversi approcci all'argomento, utilizzando sia metodi di ricerca quantitativi su dati statistici, che metodi di ricerca qualitativa per l'analisi dei questionari. Il capitolo 6 applica un modello di simulazione energetica allo studio dell'impatto del comportamento al fine di costruire scenari per supportare i decisori locali nelle loro scelte. Infine, nel capitolo 7 vengono illustrati i risultati di un’analisi multi-criterio per determinare l’impatto degli utenti sulle strategie per il risparmio energetico e formulate nuove proposte.