Reliable and harmonised building data are key to effective renovation policies. The OBSERVE project improves data quality and exchange to help Member States implement renovation plans and energy performance standards under the Energy Performance of Buildings Directive (EPBD).
Stavros Spyridakos, Institute for European Energy and Climate Policy (IEECP), LinkedIn profile
Dimitrios Athanasiou, Institute for European Energy and Climate Policy (IEECP), LinkedIn profile
Shima Ebrahimi, Institute for European Energy and Climate Policy (IEECP), LinkedIn profile
(Note: Opinions in the articles are of the authors only and do not necessarily reflect the opinion of the European Union)
Accurate and accessible data are essential for effective policymaking in the building sector. Despite the strategic importance of buildings for achieving the EU’s energy and climate goals, reliable information on their energy performance, renovation status and technical systems remains fragmented and inconsistent across Member States. This persistent data gap hinders the design, monitoring and implementation of key legislative frameworks, particularly the effective transposition and implementation of the Energy Performance of Buildings Directive (EPBD).
To address this challenge, the revised EPBD introduces key provisions calling for harmonised national databases, greater interoperability and the establishment of a strengthened EU Building Stock Observatory (EU BSO). However, many countries continue to face challenges linked to legacy systems, inconsistent methodologies, and limited institutional capacity to manage comprehensive building datasets.
In this context, the OBSERVE project, funded under the LIFE Clean Energy Transition programme, supports six Member States (Croatia, Cyprus, France, Greece, Italy and Spain) in designing and deploying national building stock observatories. It focuses on data governance, helping Member States establish the structures, protocols, and coordination mechanisms needed to manage building-related data effectively. In practice, OBSERVE assists Member States in meeting their reporting obligations for the building sector under the EPBD, the Energy Efficiency Directive (EED) and other building-related policy requirements, such as those under the Governance Regulation and National Energy and Climate Plan (NECP) reporting. The project defines the structure and architecture of national databases for the energy performance of buildings and develops standardised protocols to gather, combine and manage data from different sources. A central part of the project is engaging relevant stakeholders at the national level to improve coordination and ensure that different databases and tools can operate together effectively. In line with this approach, OBSERVE guides national authorities in developing archetypes of national building stock observatories and in standardising protocols for systematic data collection and aggregation. This ensures clarity on what constitutes a national observatory and on what OBSERVE offers: a consistent framework that can be applied across Member States.
Reliable, high-quality building stock data are fundamental for effective renovation planning and for the rigorous enforcement of EU energy policies. Without a consistent overview of building characteristics, policymakers cannot identify the least efficient buildings, target renovation investment effectively or measure progress towards long-term decarbonisation goals. Historically, fragmented or outdated data systems have undermined Member States’ ability to develop evidence-based policies and weakened the European Commission’s capacity for oversight.
However, significant differences persist across Member States. Where data infrastructures are mature, authorities translate indicators into clear renovation milestones and operational monitoring. Where systems are fragmented, it is harder to set precise targets, and implementation becomes uneven, leading to less efficient use of EU funds. The Commission Staff Working Document analysing the long-term national renovation strategies reached the same conclusion: submissions varied in scope and detail, data types differed across countries, and, in many cases, greenhouse gas reduction data were missing, undermining comparability and hampering an EU-level view of cumulative impact. In practice, Member States continue to face difficulties in providing complete and consistent reporting, despite the reinforced obligations introduced by the recast EPBD.
Beyond these reporting gaps, further challenges remain in bridging the technical and social dimensions of data governance. In many countries, datasets on residential buildings are relatively well developed, whereas information on the non-residential sector remains fragmented or outdated. Data on technical systems, such as the type and efficiency of heating and cooling installations, are often missing or insufficiently detailed, making it difficult to model the impact of Minimum Energy Performance Standards (MEPS) or to design effective renovation programmes. These findings underline the need for observatories to capture not only technical performance but also social vulnerability, ensuring that renovation measures are ambitious, equitable and targeted towards those who need them most.
Under the recast EPBD, each Member State is required to gather comprehensive data on its building stock and to develop a National Building Renovation Plan (NBRP) as the central instrument for long-term renovation governance. According to Article 3 and the associated Annex II template, the plan must include: (i) an overview of the national building stock, disaggregated by type; (ii) a roadmap with nationally established targets for 2030, 2040 and 2050, accompanied by measurable progress indicators; (iii) an overview of planned policies and measures; and (iv) an outline of investment needs and potential financing sources to support implementation.
Draft NBRPs must be submitted to the European Commission by 31 December 2025. The Commission will review these drafts and may issue recommendations within six months. Member States must take due account of these recommendations before submitting their final NBRPs by 31 December 2026. The process should be preceded by a national public consultation, thereby ensuring that stakeholder views are considered and that the plans are responsive to national needs and contexts.
The Commission has also provided supporting tools, including an annotated version of the Annex II template and a spreadsheet model for data collection. While their use is voluntary, these instruments aim to standardise reporting and facilitate the comparability across national plans. This represents a significant improvement over the previous long-term renovation strategies, which, as highlighted in the Commission Staff Working Document SWD/2022/375, were often inconsistent in scope and detail and frequently omitted key indicators, notably greenhouse gas reduction trajectories.
By developing an indicator template aligned with Annex II of the EPBD, the indicators defined in the EU BSO and the data sets used for NECP reporting, OBSERVE directly assists national authorities in transforming fragmented data into a structured and comparable format suitable for NBRPs. At the same time, OBSERVE emphasises data governance by promoting clear institutional arrangements, interoperability and coordination among relevant actors. This approach enhances the reliability and transparency of reported information and makes cross-country benchmarking more feasible. In this way, OBSERVE helps ensure that NBRPs evolve beyond formal compliance documents and serves as strategic, data-driven instruments for investment planning, monitoring renovation progress and aligning national actions with the Union’s climate and energy objectives.
The recast EPBD introduces MEPS as a central instrument for reducing energy use in the worst-performing segments of the building stock. Under Article 9, Member States must ensure that: (i) the average primary energy use of residential buildings is reduced by at least 16% by 2030 and 20–22% by 2035 compared with 2020 levels, with at least 55% of this reduction achieved through the renovation of the worst-performing 43% of dwellings; and (ii) at least 16% of the worst-performing non-residential stock is renovated by 2030, rising to 26% by 2033. These binding requirements establish a predictable and enforceable trajectory for renovation, directly linking national policies to the Union’s 2030 and 2050 climate objectives.
Meeting these obligations requires Member States to develop robust governance frameworks underpinned by reliable data. A clear overview of the building stock is a prerequisite for defining the worst-performing segments and applying MEPS fairly. This entails combining data on energy performance, tenure and typology, and ensuring that they are consolidated within the national databases required by Article 22. These databases must integrate information from energy performance certificates (EPCs), building renovation passports, inspections and measured or calculated energy use, while the interoperability and access provisions of Article 16 guarantee that building owners and authorised actors can access and use the information transparently. Without these data systems, it is not possible to prioritise building types, monitor compliance or enforce standards effectively.
In this context, the OBSERVE project provides Member States with practical tools to make MEPS operational. The information to be collected for the national building stock observatories in six pilot countries (Croatia, Cyprus, France, Greece, Italy and Spain) includes worst-performing buildings, while the project integrates existing data sets, such as EPCs, cadastral information and socio-economic indicators, into a coherent framework. This enables governments to identify the worst-performing stock more precisely and to monitor compliance against defined targets. In addition, OBSERVE strengthens the governance dimension of data, helping national administrations coordinate across institutions, improve data interoperability and establish durable monitoring processes. In this way, the project complements the legal requirements of the EPBD and enables MEPS to function as effective and enforceable standards rather than aspirational goals.
The OBSERVE project directly supports six Member States in developing observatories that consolidate building data from diverse sources, including EPCs, cadastral records and socio-economic indicators. By promoting common methodologies and ensuring data comparability, OBSERVE facilitates integration with the EU BSO, thereby enhancing the Union’s ability to monitor compliance at the European level. Through these efforts, national administrations are equipped with coherent, actionable data systems that underpin both the preparation of NBRPs and the implementation of MEPS, ensuring that policies are realistic, enforceable and socially fair.
Figure 1. The OBSERVE project's objectives and workflow.
This involves mapping national registries for EPCs, cadastre databases, household energy consumption surveys and any parallel initiatives at the municipal or regional level. The analysis is not limited to technical data but also considers the institutional and administrative frameworks that determine how information is collected, validated and shared. Through this assessment, OBSERVE identifies both the technical gaps and the governance weaknesses that hinder the creation of robust observatories.
Building on this review, OBSERVE develops standardised protocols for data collection and management. These protocols ensure that information from different sources can be combined consistently, enabling governments to create comprehensive databases that accurately reflect their entire building stock. The emphasis on standardisation is critical: compliance with MEPS depends on comparability across Member States, and only harmonised indicators make it possible to assess whether all countries are progressing towards the same objectives. The project does not impose a one-size-fits-all model but adapts its technical solutions to the administrative realities of each country. In this way, national observatories are tailored to local contexts while remaining aligned with the requirements of the EPBD and the EU BSO.
A key element of the project is aligning national observatories with the EU BSO. By creating direct links between national and EU-level data sets, OBSERVE ensures a seamless flow of information and enables transparent monitoring of progress on MEPS. This connection enhances both national accountability and EU-wide comparability, enabling the European Commission to assess collective progress towards climate neutrality in the building sector.
Beyond its technical activities, OBSERVE places strong emphasis on governance and the exchange of best practices. The project documents and disseminates successful approaches for managing observatories, engaging stakeholders and ensuring the long-term sustainability of data systems. These best practices form a knowledge base that other Member States can draw upon when developing or upgrading their own observatories. In this sense, OBSERVE is not only a technical project but also a capacity-building initiative that strengthens the institutional foundations necessary for long-term compliance with MEPS.
The impact of OBSERVE extends beyond the six pilot countries. By providing a methodology for data harmonisation, institutional capacity building and EU-level integration, the project is laying the groundwork for an EU-wide transformation in how building data is managed. For MEPS in particular, this transformation is vital: only by knowing where the worst-performing buildings are, how much energy they consume and who occupies them can Member States design targeted policies that meet energy efficiency goals while delivering social benefits.
Table 1. OBSERVE contributions to MEPS and NBRPs design and implementation.
Professionals and institutional representatives engaged in building data management, energy performance monitoring, or the design of national renovation policies are invited to contribute to the OBSERVE project survey on national Building Stock Observatories: EU Survey. The survey aims to gather insights that will support the improvement of data governance frameworks and inform the establishment of harmonised, interoperable observatories across Member States.
The recast EPBD establishes both NBRPs and MEPS as central instruments for steering the decarbonisation of the building stock. Effective compliance with these provisions depends on the availability of robust national observatories capable of delivering reliable, comparable, and policy-relevant data. Observatories enable Member States to establish accurate baselines of building performance, identify priority cohorts within the building stock and design renovation pathways that are both targeted and equitable. They also strengthen accountability through transparent monitoring of progress towards binding milestones, ensuring that renovation measures achieve the intended energy savings, reduce greenhouse gas emissions and safeguard social equity. From a policy perspective, three implications stand out. First, data governance is as important as technical capacity. Member States need clear institutional arrangements, interoperability frameworks and accountability mechanisms to ensure that observatories are sustained over time and not treated as one-off projects.
The OBSERVE project demonstrates how national building stock observatories can provide this foundation. By consolidating technical data from EPCs, cadastral records, and inspections and by integrating socio-economic indicators, observatories enable Member States to design renovation pathways that are both targeted and equitable. They also strengthen national and EU-level accountability by ensuring that progress towards MEPS and NBRPs can be tracked in a consistent and comparable manner. Equally important is the project’s contribution to data governance, in line with Articles 16 and 22 of the EPBD. By promoting interoperability, clarifying institutional responsibilities and facilitating integration with the EU BSO, OBSERVE ensures that national observatories are sustainable tools for long-term compliance rather than short-term reporting exercises. In this way, robust data serve as the bridge between policy ambition and effective, inclusive renovation action.
