Search Results (54)

This paper presents a comprehensive economic comparison between renewable and fossil-fuel-based heating systems for a newly constructed residential building in Kraków, Poland, over the period 2022–2030. The analysis introduces the concept of Corrected Final Energy Consumption (CFEC) as a harmonized measure for comparing various energy sources and applies the Present Value of Total Lifecycle Cost (PVTLC) as an appropriate financial metric for non-commercial residential investments. Four heating options were examined: district heating system (DHS), gas boiler, air-to-water heat pump, and heat pump combined with photovoltaic (PV) panels. Based on real tariffs and standardized data from the Energy Performance Certificate (EPC), the DHS option demonstrated the lowest lifecycle cost, while the air-to-water heat pump—despite environmental advantages—proved the most expensive without substantial subsidies. Sensitivity analyses confirmed the strong influence of investment subsidies and fuel price fluctuations on the competitiveness of alternative systems. The findings highlight the methodological shortcomings of conventional annual-cost approaches and propose PVTLC as a more reliable decision-making tool for residential energy planning. The study also discusses regulatory, climatic, and behavioral factors affecting investment outcomes and emphasizes the need to integrate financial, environmental, and social criteria when evaluating household-level energy solutions. Full article

In response to the pressing need to increase energy efficiency in buildings, new regulations are continually being introduced to enforce higher standards. The recent recast of the Energy Performance of Buildings Directive (EPBD IV) emphasizes the establishment of national performance standards, which will supposedly be based on the national Energy Performance Certificate (EPC). However, energy certifications across several European countries rely on a quasi-steady state approach, which fails to accurately represent real-performance conditions due to inherent limitations. This is more evident in buildings located in warm climates, where actual energy demands far exceed those predicted by energy certifications. To address these discrepancies, a shift towards dynamic performance assessment methods is pivotal. This research compares the heating and cooling energy demand of an office building using two approaches: the quasi-steady state, prescribed by the Italian standard, and the dynamic state. After calibrating the dynamic model, it was employed to perform a simulation incorporating more detailed user profiles and boundary conditions than those used in the quasi-steady state method. This approach allows the preservation of both reasonable accuracy and practical applicability. Finally, a sensitivity analysis of influential parameters seeks to elucidate the main causes of divergence between simulated and measured performance and to identify opportunities for improving EPC. The simulation outcomes indicate that, while the stationary model yields heating energy demand relatively aligned with the measured data, it shows substantial discrepancies (about 50%) in the cooling predictions. Moreover, the findings reinforce the inadequacy of the simpler approach and advocate for the integration of dynamic state simulation in energy performance assessment, aligning with the objectives of the recent EPBD. Full article

As climate policy and energy costs increasingly influence housing markets, understanding how energy efficiency is capitalized into home prices has become a critical question for both researchers and policymakers. While prior studies confirm the existence of a green premium—the price advantage of more energy-efficient homes—less is known about how this premium evolves over time in response to shifting regulations, awareness, and market conditions. This study provides new empirical evidence on the dynamic valuation of energy efficiency in the London housing market between 2013 and 2021. Using a repeat-sales framework, we isolate within-property price changes and examine how energy performance is capitalized over time. We find that the green premium associated with higher current energy efficiency strengthened steadily, rising from statistically insignificant levels in 2013 to approximately 0.47% per Energy Performance Certificate (EPC) point by 2021. Meanwhile, the price penalty for a large efficiency gap, reflecting unrealized upgrade potential, narrowed substantially in 2020 and 2021, indicating a marked reduction in buyers’ aversion to less efficient homes. This study adds a new dimension to the green premium literature. It provides empirical evidence that the relationship between energy efficiency and housing value is not static, but responsive to regulatory, economic, and social changes. By tracking year-by-year changes in London, our analysis offers insight into how quickly market preferences adjust and how interventions like minimum efficiency standards translate into property values. This enriched understanding moves the field beyond the question of whether a green premium exists, to how and why it evolves. Full article

Historic buildings are often assumed to have poor energy performance, and energy optimization of the buildings is perceived as threatening their cultural values. This study tests these assumptions. First, it examines the energy performance of Danish historic apartment buildings (buildings constructed before 1950 with a high preservation value, according to the national SAVE system (Survey of Architectural Values in the Built Environment)). Second, it assesses the extent to which the energy improvements in the historic buildings conflict with their historic value. An analysis of energy performance certificates (EPC) in 13,000 Danish historic apartment buildings reveals that they perform no differently than apartment buildings with a low preservation value, with 46% of historic apartment buildings achieving an EPC rating of “C”. Nevertheless, significant potential for further energy improvements is identified. Expert interviews and three case studies indicate that typical interventions for enhancing buildings’ energy performance rarely interfere with its historic values. This is partly due to structural conditions where shoulder-by-shoulder location, high building compactness, and supply with district heating gives a beneficial foundation for a high energy performance. Potential conflicts between energy improvements and historic values exist but are often resolved through dialogue between local authorities and owners about the interventions. Full article

Residential heritage buildings (RHBs) are facing complex conservation challenges due to national policies aimed at achieving carbon emission reductions and associated retrofit recommendations. This long-term study (2007–ongoing) focuses on how such nationwide policies, particularly energy performance certificates (EPCs) and minimum energy efficiency standards (MEES), affect a cluster of 12 RHBs on the National Trust’s Wallington Estate in Northumberland, England. Data were collected using a combination of building measurements and survey observations, alongside assessment of tenant behaviours through an interview process. The research findings revealed a 53% average improvement in EPC ratings following a retrofit. However, the tenant interviews exposed some key limitations in current policy tools, including their failure to reflect actual energy use and behavioural patterns. For instance, despite improved EPC scores, some tenants reported high fuel costs and continued to experience heat loss and dampness in the RHBs. These novel findings of this longitudinal study challenge the suitability of current retrofit metrics and advocate for a people-centric and context-specific approach to energy efficiency in heritage buildings. They also highlight the drawback of proposed minimum EPC ‘C’ standards within the UK’s existing housing stock, particularly in relation to idiosyncratic RHBs. Full article

Conventional methods of studying houses’ Energy Performance Certificates (EPCs) typically fail to investigate the impact of interrelated contextual elements instead fixating exclusively on the specific attributes of individual houses. This study presents a new method that combines network graph analytics (NGA) with interactive visual analytics to investigate hidden linkages at the individual house level. Our proposed platform collects and analyses data related to housing attributes, creates a network based on the links between these attributes, and employs sophisticated graph algorithms to provide visual representations. Users have the ability to dynamically choose postcodes, metrics, and attributes, which, in turn, generate layouts of networks that provide valuable insights. The visualisation utilises colour gradients and node metrics to improve the comprehensibility of energy performance areas. The platform enables homeowners and stakeholders to comprehend the interrelationships between aspects such as neighbouring housing features, and house infrastructure. The results prove the efficacy of the strategy by giving a collection of case studies that encompass various Energy Performance Certificates (EPCs) ranging from A to G. Each case study demonstrates the evolution of network architectures and visual assessments, showcasing the energy performance linked to certain EPC ratings. The platform offers a user-friendly interface for stakeholders to investigate and understand attribute relationships. Full article

This research presents a multi-scale framework designed for assessing the energy performance and climate vulnerability of three existing residential buildings in a small Central Italian municipality. By integrating dynamic energy simulations with high-resolution climate projections, the study investigated how the selected building typologies responded to changing environmental conditions. Validation against Energy Performance Certificates (EPCs) confirmed the framework’s robustness in accurately capturing energy consumption patterns and assessing retrofit potential. The results revealed a general reduction in heating demand accompanied by an increase in cooling requirements under future climate scenarios, with notable differences across building types. The reinforced concrete building showed greater sensitivity to rising temperatures, particularly in cooling demand, likely due to its lower thermal inertia. In contrast, masonry buildings achieved more substantial energy savings following retrofit interventions, reflecting their initially poorer thermal performance and outdated systems. Retrofit measures yielded significant energy reductions, especially in older masonry structures, with savings reaching up to 44%, underscoring the necessity of customised retrofit strategies. The validated methodology supports future wider applicability in regional energy planning and aligns with integrated initiatives aimed at balancing climate adaptation and cultural heritage preservation. Full article

The digital transition and decarbonization are strategic European objectives, supported at different levels by the Green Deal, the Energy Performance Building Directive (EPBD), and policies and tools such as the Energy Performance Certificate (EPC) and the Smart Readiness Indicator (SRI). The SRI measures a building’s ability to use intelligent technologies to reduce its consumption and increase the energy awareness of occupants for energy efficiency. Furthermore, today, it has a limited impact on national regulations and public decision-making. Its application presents challenges including those related to heritage conservation. This paper contributes to the Italian SRI framework through an experimental application in the renovation of a historic building in the metropolitan city of Reggio Calabria (Italy). The analysis evaluates the SRI’s adaptability by comparing its pre-renovated state, current state, and pre-design plan. The SRI calculation integrates assessment tools with BIM models for a potential future digital twin approach. The study, part of a funded national research project, aims to enhance policies for digitalization in the green transition. The paper is organized into the Introduction; Materials and Methods, which contains the methodological approach; Results; and Discussion and Conclusions. Following the experimental application, the results show that standardizing the SRI approach could enhance energy efficiency and digitalization in buildings. Full article

This study examines the Carbon Performance Gap (CPG) and Energy Performance Gap (EPG) of school buildings in Osijek-Baranja County in Croatia. The variance between the predicted energy efficiency of a building, as indicated by the energy performance certificate (EPC), and its actual performance in terms of energy consumption, is often referred to as the EPG while the variance between the predicted carbon emission of a building from the EPC and its actual emission is referred to as CPG. This study aims to determine the extent of CPG and EPG between actual energy consumption/carbon emission and the calculated, which is presented in EPCs of school buildings. The average EPG among the analyzed schools was found to be 71.73% while the average CPG was found to be 78.77%. The analysis also revealed a substantial average annual difference in heating costs attributable to the EPG. By addressing EPG and CPG while optimizing energy usage, educational institutions can achieve substantial cost savings and contribute significantly to sustainability goals. Full article

Buildings account for a significant share of global energy consumption and carbon emissions, making deep renovations essential for climate mitigation. Renovation passports (RPs) are an emerging concept still in the early stages of development, designed to provide structured step-by-step renovation roadmaps that prevent lock-in effects and optimise energy performance over time. However, their large-scale adoption in the European Union (EU) remains limited due to technical, financial, behavioural, and policy challenges. This study conducts a Systematic Literature Review (SLR) to identify key strategies for the successful development and large-scale implementation of RPs in EU. A total of 217 research articles from Scopus and ScienceDirect, along with 99 EU policy documents and 16 Building Performance Institute Europe (BPIE) reports, were analysed to assess the technical, financial, behavioural, and policy dimensions of RP adoption. Our findings highlight the role of digital tools like Building Information Modelling (BIM), digital building logbooks (DBLs), and one-stop shops (OSSs) in improving RP usability and accessibility. Financial barriers, such as high upfront costs and fragmented funding, require harmonised incentives, green loans, and energy performance contracting. Behavioural factors, including homeowner awareness, trust in renovation services, and decision-making complexity, also influence RP adoption. This study underscores the need for stronger policy integration between RPs and energy performance certificates (EPCs), improved financial instruments, and enhanced stakeholder engagement. By addressing these gaps, this research provides actionable recommendations for policymakers and stakeholders to accelerate the adoption of RPs and contribute to the EU’s Renovation Wave strategy and broader climate neutrality objectives. Full article

To effectively decarbonize Europe’s building stock, it is crucial to monitor the progress of energy consumption and the associated emissions. This study addresses the challenge by developing a national-scale urban building energy model (nUBEM) using artificial intelligence to predict non-renewable primary energy consumption and associated GHG emissions for residential buildings. Applied to the case study of Spain, the nUBEM leverages open data from energy performance certificates (EPCs), cadastral records, INSPIRE cadastre data, digital terrain models (DTM), and national statistics, all aligned with European directives, ensuring adaptability across EU member states with similar open data frameworks. Using the XGBoost machine learning algorithm, the model analyzes the physical and geometrical characteristics of residential buildings in Spain. Our findings indicate that the XGBoost algorithm outperforms other techniques estimating building-level energy consumption and emissions. The nUBEM offers granular information on energy performance building-by-building related to their physical and geometrical characteristics. The results achieved surpass those of previous studies, demonstrating the model’s accuracy and potential impact. The nUBEM is a powerful tool for analyzing residential building stock and supporting data-driven decarbonization strategies. By providing reliable progress indicators for renovation policies, the methodology enhances compliance with EU directives and offers a scalable framework for monitoring decarbonization progress across Europe. Full article

The article presents an analysis of changes in energy efficiency of new office buildings designed and constructed during the implementation period of the Energy Performance of Buildings Directive (2014–2024). Common criteria on energy efficiency were collected from Energy Performance Certificates (EPCs) and processed. The changes in final and primary energy for space heating, cooling and hot water production of certified office buildings were determined, and the improvements in buildings, their energy systems and energy sources were analysed. It was determined that buildings of Class C, designed between 2006 and 2017, showed an average thermal energy consumption for heating of 61, for cooling of 13 and for hot water production of 30 kWh/(m²·year), while buildings of Class A++, designed after 2020, consumed, respectively, 6, 9 and 17 kWh/(m²·year). The main reasons for these changes in energy consumption are the significant improvement of thermal insulation, increase of renewable energy in the heat supplied by district heating, the use of heat pumps for cooling, more efficient hot water boilers and optimized and insulated distribution pipelines. Even better results were hindered by the increased area of glazing, insufficient use of solar protection, users’ preference for buildings of complex shape, and technically complicated electricity production. The results revealed that EPCs are an appropriate database for the analysis of changes in energy efficiency of buildings and for setting tasks for further improvement. Full article

High-performance green buildings mitigate the adverse environmental effects of energy consumption and carbon emissions while simultaneously demonstrating that sustainability does not mean compromising utility, productivity, or comfort. We need to address the identified gap in the evolution of energy-efficient structures facilitated in building applications to enhance energy usage without mitigating comfort. The aim of this study was to provide a review of the current methods used to assess energy efficiency in buildings in Malta through secondary data and to supplement this with qualitative data from interviews. The study investigated the importance of certification, compulsory legislation, and regulations implemented by local authorities and the European Union to incentivise energy performance measures. The findings, supplemented with qualitative data from representatives of public entities, show that most participants agreed that the current method of assessing needs requires a complete overhaul in order to promote a proactive approach to sustainable development. Recent public awareness has highlighted the limited understanding of sustainable practices implemented in buildings to capture and conserve energy. However, it is widely recognised that the building industry has significant potential for energy savings, which applies to both new constructions and existing structures, but the current level falls short of what is necessary in Malta. The study findings emphasise the primary energy users and pinpoint the obstacles in the implementation process. In conclusion, the use of software EPRDM, which may be applied to raise the importance of energy performance in building standards, lacks a value-driven focus, resulting in its full utilisation and potential being unexplored. Future applications of this study include the categorisation of old buildings for a possible bid in energy retrofit; campaigns to promote responsiveness; and the utilisation of advanced technological tools, such as DESIGNBUILDER and related software, to enable the simulation of an optimal building envelope. While increased energy efficiency may result in elevated rental and sale prices for buildings, this knowledge, when disseminated to prospective purchasers via the energy performance certificate (EPC) system, can catalyse investments in structures that are more energy efficient for the end user. Full article

Residential buildings contribute 30% of the UK’s total final energy consumption. However, with less than one percent of its housing stock being replaced annually, retrofitting existing homes has significant importance in meeting energy-efficiency targets. Consequently, many physics-based and data-driven models and tools have been developed to analyse the effects of retrofit strategies from various points of view. This paper aims to develop a data-driven AI model that predicts buildings’ energy performance based on their features under various retrofit scenarios. In this context, four different machine learning models were developed based on the EPC (Energy Performance Certificate) dataset for residential buildings and standard assessment procedure (SAP) guidelines in the UK. Additionally, an interface was designed that enables users to analyse the effect of different retrofit strategies on a building’s energy performance using the developed AI models. The results of this study revealed the artificial neural network as the most accurate predictive model, with a coefficient of determination (R²) of 0.82 and a mean percentage error of 11.9 percent. However, some conceptual irregularities were observed across all the models when dealing with different retrofit scenarios. All summary, such tools can be further improved to offer a potential alternative or support to physics-based models, enhancing the efficiency of retrofitting processes in buildings. Full article

Energy Performance Certification (EPC) systems are pivotal in addressing the global energy challenge, particularly in the building sector. This study evaluates the efficacy of the EPC offered by the Simplified Building Energy Model interface designed to indicate compliance with the Cypriot building regulations, widely known as iSBEM-Cy Version 3.4a, by examining a typical residential unit in Cyprus. Data on construction features and electromechanical systems were collected, and actual monthly electricity and oil bills were analyzed to determine the total primary energy consumption. Various factors were considered, including energy efficiency and operational parameters for heating, cooling, lighting, auxiliary systems, and domestic hot water. The building energy performance was simulated using iSBEM-Cy, allowing for comparison with real-world energy consumption. Notable discrepancies were observed, particularly in cooling, with deviations reaching 377.4%. Conversely, domestic hot water consumption exhibited minimal variance at 7%, while heating and lighting showed moderate discrepancies (24.3% and −113.9%, respectively). This study underscores the need for rigorous evaluations to shape effective EPC and provides insights into building energy performance in Mediterranean Cyprus. This research contributes to the broader discourse on sustainable construction practices by aligning simulation results with real-world energy consumption. Full article