Energy Performance Of Buildings Directive Research Articles

Measuring the Decarbonisation Progress of Buildings Based on European Open Big Data

The European Commission (EC) has established climate neutrality by 2050 as one of its objectives. To achieve this, decarbonising the building stock is crucial since buildings are responsible for 36% of European greenhouse gas emissions. Monitoring the progress of decarbonisation is crucial to understand where we stand in terms of achieving long-term decarbonisation goals, facilitate evidence-based decision-making, promote accountability among member states (MS), and engage the public in these initiatives. However, data collection for monitoring the decarbonisation of buildings represents a challenge for MS, for which they may not be adequately prepared.To promote the collection and publication of open data, the EC has established frameworks for developing open data infrastructures within MS through various directives, offering comprehensive and well-organized information. Directives such as the Infrastructure for Spatial Information in Europe (INSPIRE), which advocates for the collection and accessibility of data in diverse topics, and the Energy Performance of Buildings Directive (EPBD), enabling the analysis of extensive information on the energy efficiency of constructed assets through the open publication of Energy Performance Certificates (EPC) databases, exemplify these efforts. However, this information often remains dispersed and narrowly focused, necessitating the integration of other data sources to extract meaningful insights.The paper delves into the benefits of georeferencing and automated cross-referencing of open data on buildings, enabling the monitoring of decarbonisation progress. To achieve this, we have developed a national-scale Urban Building Energy Model (UBEM) for Spain. This model is founded on EPCs and other open data derived from public information sources established through European directives. Additionally, we have investigated the prospect of integrating data from Digital Building Logbooks (DBL), which are emerging data repositories on buildings promoted by the EC in the forthcoming EPBD, into the UBEM to enhance the model.The study showcases significant potential in developing information on various topics, including characterising the Spanish building stock — a framework that may be extrapolated to other MS — in terms of energy performance based on location, archetype, and age. The study also focuses on estimating energy consumption and carbon dioxide emissions, monitoring the progress of renovations, evaluating the achieved energy savings, and identifying and characterising the least energy-efficient segments of the building stock.

A comparative life cycle assessment of building sustainability across typical European building geometries

In recent years, significant progress has been made in the sustainability assessment of building materials and buildings. The introduction of Environmental Product Declarations (EPDs), the development of Level(s), and the release of relevant series of standards have helped to improve the sustainability of buildings. However, a research question that remains unresolved is the lack of information related to the comparison of the sustainability performance of building units across Europe and the significance of conducting such research. This study addressed this question by implementing a comparative whole-building Life Cycle Assessment (LCA) across buildings in Europe. The study emphasizes the necessity of considering typical building geometries and thermal performance of buildings across Europe and introduces six typical building geometries for three different European clusters (northern-western, central-eastern, southern cluster). The results of this study revealed that the sustainability performance of buildings is not similar across the EU and that cost-optimal minimum thermal performance requirements for building structures have a significant impact on their environmental performance. Particularly, single-family houses in Central and Eastern Europe are responsible for 324.42 kgCO2e/m2. Contrary to this, Northern and Western European single-family buildings have the lowest environmental impact with 268.97 kgCO2e/m2. Multifamily houses in Southern Europe are responsible for 321.82 kgCO2e/m2, in Northern and Western Europe the environmental impact is 275.37 kgCO2e/m2. The outcome of this study is significant for the scientific community involved in assessing the sustainability of buildings in Europe, as it provides valuable insights into their environmental performance, considering the energy efficiency and sustainability aspects of buildings. The study's findings should be considered when setting minimum LCA-related requirements, in view of the provisions of the new EU policies expressed in the Energy Performance of Buildings Directive (EPBD) recast for defining the Global Warming Potential (GWP) of new buildings.

Ventilation system with heat recovery and PCM thermal energy storage for “free” cooling in buildings

For the conventional cooling of buildings, we are using electrical energy from the network, which increases annually due to the increase in comfort. Alternatives are being sought to reduce electricity consumption. Phase change materials (PCMs) in ventilation systems can provide us with the accumulation of night-time coolness in the summer months, resulting in a reduction in the consumption of electricity for cooling. Heat storages that take advantage of the phase change are used for short-term storage of thermal energy, as in this case, they have the greatest potential. In the introduction to the paper, a review of heat storage devices and their use is made which shows their connection with the Energy Performance Building Directive (EPBD) and the Energy Efficiency Directive (EED). Based on the measured results of the measurements in the Laboratory for Heating, Sanitary and Solar Technology and Air-conditioning (LHSA), a comparison with the model that calculates the storage of heat and cold in a phase change material (PCM - Phase Change Material) developed by a group of researchers from BUT Brno was made. With the TRNYSY software tool and the model simulations of the ventilation gains in the summer season were made and compared with the gains when using the heat exchanger (recuperator) and the PCM heat accumulator for the selected room.

A Qualitative Analysis Using Thermography for Characterization of the Built Environment

The revised Energy Performance of Buildings Directive (EPBD) recognizes nearly zero-energy buildings (nZEB) and building renovation as essential steps in the decarbonization of the built environment. A thorough understanding of existing buildings is a prerequisite for improving their thermal performance and ensuring that interventions are based on pre-existing conditions. This study investigates the use of thermography as a tool for identifying construction solutions and assessing the thermal performance of buildings. Initially, it addresses the benefits and limitations of this technique, as well as some results of a qualitative analysis and standard application of this technology. Specific conditions for capturing images on-site were identified, along with the relevant factors for interpreting thermograms under natural conditions. These images enabled the identification of previous works, changes in buildings, and the use of different materials and construction techniques, thereby contributing to the characterization of buildings. Consequently, they can be used in the diagnostic phase to enhance the accuracy of intervention solutions based on a better understanding of existing conditions.

A Novel Approach to Determine Multi-Tiered Nearly Zero-Energy Performance Benchmarks Using Probabilistic Reference Buildings and Risk Analysis Approaches

The Energy Performance of Buildings Directive (EPBD) mandates European Union Member States (MS) to conduct cost-optimal studies using the national calculation methodology (NCM), typically through non-calibrated asset-rating software. Nearly zero-energy building (NZEB) levels must be derived for each chosen Reference Building (RB), which are generally defined using deterministic parameters. Previous research proposed an innovative cost-optimal method that replaces ‘non-calibrated deterministic RBs’ with ‘probabilistically Bayesian calibrated reference building (RB)’ to better handle building stock uncertainties and diversities when deriving benchmarks. This paper aims to develop a framework to address two research gaps necessary for the successful application of the innovative cost optimal method: (1) providing objective criteria for defining NZEB benchmarks and (2) propagating uncertainties and financial risk for each defined benchmark. A robust approach for defining NZEB benchmarks according to four different ambition levels (low, medium, high, and highest) was developed by objectively considering distinct points from multiple cost-optimal plots employing different financial perspectives. Risk analysis is then performed for each defined benchmark by propagating risk from the posterior calibration parameter distributions to visualize and statistically quantify the financial risk, including robust risk, that the private investor could face for reaching each derived benchmark ambition level. The innovative cost-optimal methodology that incorporates the developed framework was applied to a hotel RB case study. The results showed that the developed framework is capable of deriving distinct benchmarks and quantitatively uncovering the full financial risk levels for the four different renovation ambition levels. The current cost-optimal method was also performed for the hotel case study with the RB defined determinitically and using the non-calibrated NCM software, SBEM-mt v4.2c. It was found that the financial feasibility and energy-saving results per benchmark are significantly more realistic and transparent for the proposed innovative cost-optimal method including a better match between the simulated and metered energy consumption with a difference of less than 1% in annual performance. Thus, the performance gap between calculated and actual energy performance that is synonymous with the EPBD methodology, as reported in the literature, is bridged. The case study also showed the importance of the risk analysis. Performing the cost-optimal analysis for a Bayesian calibrated RB using the mean value of the posterior calibrated parameter distributions without propagating uncertainty produced highly optimistic results that obscured the real financial risk for achieving the higher ambition levels of the NZEB benchmarks. Consequently, the developed framework demonstrated a time-bound tightening approach to achieve higher energy performance ambitions, improve risk transparency to private investors, and facilitate more targeted policies towards a net zero-carbon status. Thus, the proposed method considering parameter uncertainty and calibrated RBs is instrumental for devising robust policy measures for the EPBD, to achieve a realistic and long-lasting sustainable energy goal for European buildings.

CO2 emission reduction, loads analysis, and strategies for new healthcare facilities design – Application on a case study

To understand the “Zero Emission Building” goal introduced by the Energy Performance of Buildings Directive (EPBD) revision, it is certainly important to define its scope, since different considerations must be made for buildings with different uses, characteristics and locations. In this paper, the case study of a new construction hospital building is analysed, bringing attention to two main aspects: the correct identification of energy needs of the Heating, Ventilation and Air Conditioning (HVAC) systems; Mechanical, Electrical and Plumbing (MEP) design strategies aimed at minimizing CO2 emissions. To pursue these objectives, the hourly trends of energy consumption are examined, focusing on the interpretation of their distribution, the main influencing variables and on the distribution of such energy consumption among the different utilities of the analysed system. It is opinion of the authors that this in-depth study is preparatory to the proper MEP design of the systems: in fact, by knowing the most energyconsuming users and the distribution of heating and cooling loads during the year, it is possible to identify the optimal design strategies and generation technologies to reduce the consumption of Primary Non-Renewable Energy. In this regard, the choice of an ap-propriate calculation model is highlighted as crucial. Possible design strategies related to the case study under consideration are analysed in this paper, ultimately exposing the general considerations regarding the ZEB issue in the hospital setting.

Readiness of Zero-Emission Buildings (ZEBs) implementation in the European Union

The building sector plays a central role in the reduction of greenhouse gas (GHG) emissions in the European Union (EU). The revision of the Energy Performance of Buildings Directive (EPBD) sets out ambitious requirements to make the EU building stock decarbonised by 2050. The proposal for a recast EPBD introduces Zero-Emission Building (ZEB) as the building target for all new buildings as of 2030. This paper offers insights into the concept of ZEB, analysing its key methodological aspects, with a focus on ambition, the role of energy efficiency, and the role of renewable energy. Additionally, the paper evaluates the performance levels of new buildings in EU Member States, highlighting the gaps between current Nearly Zero-Energy Buildings’ performance levels and potential ZEB performance levels, specifically in terms of primary energy demand and renewable energy contribution. The findings emphasise the necessity to enhance initiatives aimed at improving energy efficiency and harnessing renewable energy sources to adopt the ambitious ZEB concept as of 2030. Additionally, the paper highlights the importance of addressing GHG emissions comprehensively, extending beyond the operational phase of a building to include embodied impacts, in order to achieve a life-cycle zero-emission building stock.

Technical-economic and financial feasibility of new technologies in the energy refurbishment of residential buildings

The revision of the Energy Performance of Building Directive (EPBD) provides for the construction of zero-emission buildings. The present work investigates possible solutions aimed at phasing out fossil fuel systems in buildings, in accordance with the EPBD requirements. An insulated residential building located in Rome is presented. The proposed refurbishment approach is based on the heating system replacement (heat pump, hydrogen fuel cell, hydrogen-ready boiler), and the use of renewable energy produced by a photovoltaic system. The results show that, although the energy optimal solution consists of the replacement of the heat plant with a heat pump coupled to both a PV and a fuel cell system, from the economicfinancial point of view the proven solution of heat pump coupled with PV is still the only feasible one.

A review of the 1-2 apartment residential building stock in Lithuania based on an analysis of Energy Performance Certificates

One of priorities of the EU’s climate change policy is the energy performance of buildings. This is reflected primarily through the series of Directives the EU has enacted along the years, but is most precisely conveyed in the Energy Performance of Buildings Directive (EPBD). As part of the European Union, Lithuania has enacted its own long-term strategy aimed at transforming the current building stock in one which is more energy efficient. Building energy certification, legalized in accordance with the requirements of the directive is the primary tool used to evaluate the energy-efficiency of a building, which includes determination of the energy consumption of a building and subsequently assigning it with an energy performance class. Energy performance certificates (EPC) are obligatory for new and existing buildings in all European Union (EU) member states and provide not only a description of the energy performance characteristics of individual buildings, but are also useful source of legal information for determination of the achievements of building energy efficiency improvement strategy. Despite the current wide spread presence of EPC analyses in other European countries, similar information on the national EPC register of Lithuania is still hardly present in research studies. To this effect this paper presents a detailed overview of the stock of Lithuanian residential 1-2 apartments buildings using data from the national EPC register. The results obtained present the impact of the implementation of EPBD on Lithuanian residential 1-2 apartments buildings, including changes in thermal insulation of building elements, heating system typology, energy consumption and CO2 emissions.

E-DYCE - Dynamic approach to the dynamic energy certification of buildings

The energy performance certification (EPC) scheme, introduced in the European Union approximately 20 years ago, has become the focus of the upcoming revision of the Energy Performance of Buildings Directive (EPBD). Despite its widespread use, the current EPC scheme has several shortcomings that need to be addressed. The Energy flexible DYnamic building Certification (E-DYCE) project has developed a dynamic approach to address these issues. The methodology includes a dynamic assessment of a building’s energy needs and comfort conditions under standard and different from standard conditions of building use to support Performance Gap (PG) analyses. The E-DYCE approach includes a dynamic building performance simulation with comfort and energy-related key-performance indicators (KPIs) measured and calculated according to E-DYCE DEPC methodology. These KPIs can inform end-users about indoor environmental quality conditions decisive for building energy performance, aid building managers in detecting dysfunctions resulting in PG, and include energy performance indexes for heating, cooling, lighting, domestic hot water, and more. Overall, the E-DYCE approach offers dynamic, reliable, and customer-tailored information and optimization possibilities to end-users while potentially resolving known shortcomings of the existing EPC schemes.

A new method for estimating the smart readiness of building stock data using display energy Certificate data

The Smart Readiness Indicator (SRI) was introduced by the revised Energy Performance of Buildings Directive (EPBD) 2018/844/EU, as a voluntary scheme for rating the smart readiness of buildings. The methodology addresses the benefits of smart technologies and their functionalities in buildings to offer low-energy, healthier, and environmentally comfortable buildings that balance the needs of occupants and the energy grid. This is a case study implementation of the SRI calculation to the university campus scale. The SRI methodology is applicable on a building-by-building basis; however, the assessment of large stocks and energy hubs is not addressed and will be the focus of this study. Other studies have proposed a method to extend the calculation to building clusters which, however, involves assessing all the buildings in the cluster in detail. The current case study extends to a much larger number of buildings, therefore, the assessment of each individual building was not considered effective. A critical implementation of the SRI calculation is presented here that leverages publicly available information like Display Energy Certificate (DEC) advisory recommendation reports for a university campus. A complex building is used to verify the proposed method based on the SRI detailed methodology. The proposed method provides a solution to the large-scale processing of building information across multiple complex buildings, hence benefiting decision-makers early on. Furthermore, the method benefits from the inclusion of building-specific recommendations based on DEC surveys. For the 98 buildings examined, a campus SRI score range has been estimated and focus areas have been identified as the foundation of smart energy and net-zero transition pathways.

The importance of organization type: Construction sector perceptions of low-carbon policies and measures

To facilitate decarbonization in the EU’s building sector, the regulatory focus is shifting towards a life cycle perspective of emissions. The EU’s path in tackling embodied emissions is under development in the revision of the Energy Performance of Buildings Directive, which is utilizing Level(s) framework and EN 15879 as a methodological foundation. Member States are at different stages in their building life cycle regulation plan and Finland is preparing normative regulations to limit the carbon footprints of new buildings. We conducted a survey on how the different actors in the construction sector perceive new low-carbon policies under development in Finland. Our findings indicate that carbon footprint policies were generally seen as functional. However, perceptions differed significantly depending on the respondent’s organization type. The respondents involved in the construction design stage generally seemed more positive about the proposed regulations, whereas advocates (associations and interest groups) were more cautious than the organizations they represented. These findings help clarify the implementation and development needs of low-carbon policies.

A Methodology Integrating the Quantitative Assessment of Energy Efficient Operation and Occupant Needs into the Smart Readiness Indicator

The Smart Readiness Indicator (SRI) was included in the third version of the Energy Performance of Buildings Directive (EPBD) and has since been used in research involving a variety of building types and climate zones. While numerous studies highlighted the qualitative characteristics of the current SRI framework, this work describes a methodology for adding quantitative features to it. It uses indicators for each effect area and proposes multiple standards as rating assessment factors. We specify the integration of this crucial component enhancing the framework. This enhanced framework is applied to a hypothetical use case, and the outcomes are compared with those of the current framework. The results demonstrate that the SRI score was increased after adding quantitative elements to the SRI framework.

Comprehensive Review and Analysis of Glazing Systems towards Nearly Zero-Energy Buildings: Energy Performance, Thermal Comfort, Cost-Effectiveness, and Environmental Impact Perspectives

The global interest in nearly zero-energy buildings (NZEBs) has led to their establishment as mandatory building objectives in Europe for all new constructions starting in 2021. The principles outlined in the Energy Performance of Building Directive (EPBD) emphasize the significance of reducing energy demand through various energy efficiency measures to achieve NZEB status. Among these measures, the utilization of high-performance glazing systems plays a crucial role in ensuring natural light, ventilation, favorable solar gain, aesthetics, and positive psychological effects in buildings, while maintaining high energy performance and thermal comfort without burdening the budget or harming the environment. The use of increasingly larger glazing areas makes this topic of great relevance. Nevertheless, numerous studies frequently overlook certain crucial aspects of glazing systems in their assessments. This review study aims to assess different glazing solutions based on four critical perspectives called “EThCE”: Energy performance, thermal comfort, cost-effectiveness, and environmental impact, considering their interrelationships. Furthermore, the importance of adopting a comprehensive approach for selecting the optimal glazing solution for NZEBs is discussed. Additionally, the relationship between glazing systems and climate change is taken into account. Ultimately, the authors propose a comprehensive approach, including all the influential factors, to assist designers and homeowners in making informed decisions regarding glazing system selection for new NZEBs or NZEB retrofits in different situations.

Towards nearly zero-energy residential buildings in Mediterranean countries: The implementation of the Energy Performance of Buildings Directive 2018 in Spain

Towards nearly zero-energy residential buildings in Mediterranean countries: The implementation of the Energy Performance of Buildings Directive 2018 in Spain

Evaluating Reduction in Thermal Energy Consumption across Renovated Buildings in Latvia and Lithuania

Currently, the optimization of thermal energy consumption in buildings is considered a suitable alternative in the construction of new buildings, as a result of which the overall energy efficiency of the building increases. Thus, this study examined the efficiency and efficacy of different building renovation packages conducted across several buildings in Latvia and in Lithuania (across a larger building stock). In the first section of this study, 13 multi-apartment residential houses with 3 building renovation packages have been investigated in the city of Daugavpils, Latvia, in order to determine the actual reduction in heat energy consumption across each of the renovation implementation packages. The study findings indicate that changes in Latvian building regulations regarding insulation thickness did not significantly impact thermal energy consumption in fully renovated buildings. However, the combination of facade renovations, upgraded heating systems, and improved ventilation systems resulted in substantial energy savings, with an average reduction of 50.59% in thermal energy consumption for space heating across the reviewed multi-apartment residential building stock. In the following section of this study, the impact of the Energy Performance of Buildings Directive (EPBD) on building energy efficiency in Lithuania has been examined. The results show that over a 10-year period in the 2000s, Lithuanian building stock experienced a 20% increase in energy efficiency, followed by an additional 6.3% increase between 2010 and 2016. The mandatory requirement for renovated buildings to achieve a minimum energy efficiency class has resulted in significant reductions in energy consumption for heating purposes. The findings underscore the effectiveness of building renovation packages and the EPBD regulations in enhancing energy efficiency and promoting sustainable building practices. The importance of heat metering, consideration of indoor air temperature, and the need to address indoor air quality during renovations were also highlighted.

Developing a New Data-Driven LCA Tool at the Urban Scale: The Case of the Embodied Environmental Profile of the Building Sector

Given the ambitious climate reduction targets of the European Commission for the building sector and the adoption of the life cycle assessment method for the environmental metrics, the authors of this research present a new tool that allows for an extensive evaluation of buildings (operational and embodied environmental profile). The tool developed is an engine written in Python that was applied to analyze the buildings of Milan, using several open databases available for the Lombardy region (Northern Italy). Approximately 240,000 building units were investigated and compared using ecoinvent 3.9.1 EN 15804 as a background library and characterization methods in compliance with EN 15978. The tool can establish reliable environmental benchmarks to implement building policies, such as climate footprint limits for new constructions as required by the recast Energy Performance of Buildings Directive (2023). This article shows the embodied impact of construction materials. The results for residential, commercial, and retail building units (old and new) are 15 kg CO2eq/(m2 of net area × year) for the entire building stock (old and new building units) and 21 kg CO2eq/(m2 of net area × year) for new buildings (nearly zero energy building units).

Comparison of calculation and consumption methods for determining Energy Performance Certificates (EPC) in the case of multi-family residential buildings in Poland (Central-Eastern Europe)

The calculation method and the consumption method are used to award Energy Performance Certificates (EPC), in accordance with the Energy Performance of Buildings Directive (EPBD) 2010/31/EU with revisions. The calculation method can be used for any type of building, regardless of the type of heat source. A good knowledge of the building is required (architectural and construction documentation, inventory of the building). The consumption method can be used only in buildings with heat and gas meters. It is not necessary to have detailed information about the building. However, this method is not applicable to offices, hotels, or production buildings with periodic breaks in heating and hot water consumption. Here, we apply the calculation method and the consumption method to analyse 15 multi-family residential buildings located in Poland (Central-Eastern Europe). Both methods gave similar values. Using the consumption method the energy indicators were slightly lower than using calculation method (on average, the results differed by approx. 14–17%). The consumption method provides a useful alternative to the calculation method, and can be tested by the scientific and expert community in other countries where it has not yet been implemented.

Setting baselines of the embodied, operational and whole life carbon emissions of the average Spanish residential building

The construction sector, responsible for 37 % of global greenhouse gas emissions and 36 % of global energy consumption, is transitioning towards a low-carbon and low-energy model. Measuring and optimising Operational Energy and related emissions in the use phase of buildings has entered both markets and regulations. However, the Embodied Energy within construction materials and respective maintenance and end-of-life processes is still in the research phase. Moreover, Global Warming Potential baselines per built square metre need to be defined in the construction sector, integrating operational and embodied impacts. This research has the main goal of identifying for the first time the Whole Life Carbon (WLC) emissions of the average Spanish residential buildings of the period 1981–2010, broken down into Embodied Carbon (EC) and Operational Carbon (OC). For this purpose, first, a regular average and homogenised average of existing European baselines was performed; next, the average Spanish residential building has been defined and modelled with a real sample from year 2013, and its emissions calculated as Scenario 0; and finally, five new scenarios have been compared in order to understand variations in WLC and their EC and OC contributions. This research shows for the average multifamily building apartment in Spain, with a mean net floor area of 73.1 m2, a WLC baseline of 1944 kg CO2-eq·m−2, 30.8 % (559 kg CO2-eq·m−2) being EC, and the remaining 69.2 % OC. In Scenarios 1 to 3, the following are identified: a WLC reduction of 26.0 % (9.2 % EC) by using wood window frames, 0.8 % (2.7 % EC) by laying a wood inner floor, and 16.1 % (1.0 % EC) by insulating walls with recycled cork. All three items are calculated together in Scenario 4, giving a 36.9 % WLC reduction (9.5 % EC). Finally, Scenario 5 was modelled upon Scenario 4 materials, complying with the upcoming European Energy Performance of Buildings Directive as if built in 2021, reaching a potential WLC reduction of 63.4 % (2.8 % EC) from the original Scenario 0. These figures support technical and policy trends towards minimising the impacts of buildings. Focusing on decarbonisation, targets of over 60 % appear feasible with existing market solutions. Reductions of >80 % are also derived from other impact categories, such as Ionizing Radiation, Marine Eutrophication, and Water Consumption, while Freshwater Ecotoxicity increases by 15 %. The 18 ReCiPe Midpoint indicators plus Energy Footprint, are reduced by an average of 50.4 %.

Staged renovation and the time-perspective: Which other metric should be used to assess climate-optimality of renovation activities?

With the sudden threat of gas supply interruption through the Ukraine-Russian war, the importance of improving buildings' energy efficiency has become even more relevant. Mainly during 2022 and 2023, there was an intensive process to launch a recast Energy Performance of Buildings Directive, to assure favourable policy framework conditions. In this context, the current paper addresses the following question: How does the consideration of staged renovation change the view of cost-optimal building standards and related building renovation assessments? For that, this paper analyses the staged building renovation and the time perspective when they are performed related to cost-optimal building standards. The workflow relies on the following methods: (1) cost-optimal methodology and global costs calculation and (2) mixed-integer optimisation to derive optimum timing of staged renovation under household budget constraints. The analysis consists of a country comparison (Spain, Germany and Sweden) and an evaluation of different energy efficiency measures. The main conclusion is that in staged renovations, the cost-optimal variant was in many cases the climate-optimal one when using the metric cumulative CO2 emission. Although the metric “cumulative CO2 emissions” is not suggested by the EPBD yet, this metric represents the depth and time perspective of renovation activities. Therefore, in order to speed up building stock decarbonisation cost-optimal methods alone are not sufficient to increase buildings' energy efficiency and climate neutrality in a fast way. In addition to that, considering households’ budget as optimisation variable can be an effective to assess the time when renovation activities are performed.