Master's Thesis submitted to the MSc Programme in Construction Project Management, Hellenic Open University

Abstract

The energy upgrading of the building stock is a critical component of the energy transition and the achievement of sustainable development goals in Greece and the European Union. In this context, the present study investigates the contribution of environmental design and "Exoikonomo" (Energy Saving) programs to improving the energy efficiency of buildings and reducing the environmental impact of the building sector. The methodological approach is based on leveraging the institutional and regulatory framework, analyzing the progress and outcomes of energy upgrade programs, and processing quantitative data regarding the beneficiary dwellings, their energy rating, energy savings, and the reduction of carbon dioxide emissions. At the same time, a questionnaire-based survey examines parameters related to the implementation and acceptance of energy upgrade interventions. The findings are used to evaluate the effectiveness of existing policies and to highlight the importance of environmental design and energy efficiency. Finally, the study aims to contribute to an assessment of the current situation and to identify prospects for strengthening policies regarding the energy upgrading of the building stock.

Keywords: Energy upgrade, RES, conventional energy sources, energy conservation, environmental design.

1. Introduction

The energy upgrading of residential building stock has emerged as a key priority of energy and environmental policy, particularly over the last decade. The economic crisis and, more recently, the energy crisis—combined with rising energy costs, have heightened the need to curb energy consumption and residential operating costs. This need is particularly acute for the existing building stock, a significant portion of which is characterized by age, inadequate thermal insulation, and high energy losses.

At the same time, the residential sector's significant reliance on conventional energy sources and its high level of energy consumption contribute to increased carbon dioxide emissions and, consequently, exacerbating environmental impacts and climate change. In this context, the energy upgrading of buildings serves as a key mechanism for improving energy efficiency and reducing the environmental footprint through technical, structural, and energy-related interventions aimed at lowering energy demand and optimizing the buildings' overall energy performance.

At the same time, the utilization of low-impact and renewable energy sources—as well as the integration of environmental design principles into the planning and implementation of energy-related interventions—is gaining particular importance. This approach links energy efficiency with the selection of appropriate materials, technologies, and design practices, aiming to create buildings that meet modern standards for sustainability and carbon emission reduction.

In this context, the present study investigates the energy upgrade practices applied in the residential sector and evaluates the contribution of renewable energy sources and environmental design to improving the energy efficiency of dwellings.

The research approach combines a review of literature and comparative analysis with primary field research using a structured questionnaire, involving 100 individuals who have either completed or are currently undertaking an energy upgrade of their homes. The study examines users' perceptions, priorities, and level of familiarity regarding energy-related interventions and sustainable technologies.

The study primarily focuses on investigating the extent to which renewable energy sources can substitute for conventional energy solutions, the impact of material selection on residential energy efficiency, and the applicability of environmental design principles to modern energy-upgrading practices. Additionally, it evaluates user attitudes toward such interventions and sustainable energy technologies, aiming for a comprehensive assessment of the factors influencing their adoption in the residential sector.

1. Methodology

The methodological approach of this study was based on a combination of literature review and primary research. Initially, a literature search was conducted to gather and utilize scientific and institutional information regarding the energy upgrading of buildings, conventional and renewable energy sources, and the principles of environmental design. This literature review served as the basis for clarifying the theoretical framework and addressing the key parameters of the issue under examination.

At the same time, primary research was conducted using a structured questionnaire. The questionnaire was designed based on key themes identified during the literature review and, following review and final approval, was distributed electronically. A total of 100 individuals residing in various geographical areas participated in the study, with the aim of capturing diverse views and experiences regarding the energy upgrading of homes.

Data collection focused on energy-related interventions that have been implemented or are currently underway, the use of conventional and renewable energy sources, the selection of materials and technologies, and the users' level of familiarity with and perceptions of energy upgrade practices. The data gathered from the 100 questionnaires were processed and used to comparatively assess the responses and draw conclusions regarding the study's objectives and research questions.

Literature review → questionnaire design → 100 participants → electronic distribution → data collection/processing → drawing conclusions.

• Results and Discussion

The research findings indicate that energy upgrade interventions contribute significantly to reducing energy consumption and residential operating costs. Participants place primary emphasis on thermal insulation and the replacement of window and door systems, while also demonstrating a positive attitude toward the use of renewable energy sources. Satisfaction with the interventions and the intention to undertake further energy upgrades confirm the positive reception of these practices.

At the same time, the economic dimension emerges as a key factor in decision-making, with the reduction of energy costs and the potential for recouping the investment significantly influencing household choices. In this context, subsidy programs serve as a vital tool for boosting participation and facilitating the implementation of energy-related interventions.

However, the assessment of the interventions' effectiveness could be enhanced through the systematic recording of actual energy consumption before and after the upgrade, as well as through techno-economic analyses of the performance of individual solutions. Of particular interest is also the investigation of different combinations of interventions and the comparison of the theoretically calculated energy performance of the buildings with their actual performance, taking into account user behavior and actual operating conditions.

Overall, the energy upgrading of the existing building stock is an issue with technical, economic, and social dimensions. The effective implementation of relevant policies requires a combination of appropriate technical interventions, financial incentives, and a reliable assessment of actual energy performance, with the aim of achieving a long-term reduction in energy consumption and the environmental footprint of residential buildings.

1. Conclusions

This study highlighted the importance of the energy upgrading of residences as a means of curbing energy consumption and operating costs, as well as a factor in improving the energy and environmental performance of the residential building stock. The results of the research, conducted on a sample of 100 individuals, provide an overview of housing characteristics, the interventions selected, and the factors influencing the relevant decisions.

The sample consists primarily of individuals aged 35–50 with a high level of education and stable professional and family circumstances. Most of the dwellings in the sample were built between 1980 and 2000, range in size from 50 to 100 sq.m., and exhibit relatively low energy efficiency—a fact that highlights the significant room for improvement that still exists within the existing Greek building stock.

Regarding interventions, participants prioritize solutions concerning the building envelope, most notably thermal insulation and the replacement of window and door systems—while also showing increased interest in utilizing renewable energy sources, particularly solar energy systems. The choice of these specific interventions indicates that energy upgrades are approached primarily through practical solutions capable of curbing energy losses and immediately improving the home's operational performance.

A particularly significant finding is the dominance of the economic factor in decision-making. Reducing energy consumption costs and saving money appear to be the primary drivers for implementing energy-related interventions. Environmental protection, energy autonomy, and improved living conditions play a complementary role, yet they do not carry the same weight as economic benefits.

At the same time, the utilization of subsidy programs by a significant number of participants confirms the importance of financial incentives for the implementation of energy-related investments. Covering part of the initial cost appears to facilitate the decision of households to proceed with interventions that, without financial support, might have been delayed or never carried out.

The overall assessment by participants is positive, as they report reduced energy consumption, satisfaction with the implementation of the interventions, and a favorable view regarding the payback of the associated investment. Furthermore, the strong intention to undertake additional interventions in the future indicates that, following the experience of the energy upgrade, users recognize its benefits and show a more positive attitude toward adopting sustainable energy solutions.

Overall, the findings indicate that the energy upgrading of homes is an option primarily driven by the need to reduce energy costs, yet it can simultaneously contribute to improving energy efficiency, living standards, and the environmental performance of buildings. Strengthening funding programs, better informing households, and promoting solutions that combine energy efficiency with the use of renewable energy sources can serve as key factors in the further adoption of energy upgrades within the residential sector. At the same time, the research findings highlight the value of integrating environmental design principles into relevant interventions, ensuring that energy upgrades are viewed not merely as technical or financial measures, but as part of a broader approach to the sustainable design of the building stock.

ACKNOWLEDGEMENTS

Upon the completion of this work, I would like to express my sincere thanks to my supervising professor, Ms. Cleopatra Petroutsatou, for her invaluable guidance, continuous support, and excellent collaboration throughout the course of the project. Her assistance and advice contributed significantly to the completion of this study.

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