Introduction

High-quality data are increasingly recognised as a cornerstone for improving the energy performance of buildings and for enabling the effective implementation of European climate and energy policies. Despite the increasing policy attention given to renovation and energy efficiency, significant data gaps persist across most of the building stock, limiting the effectiveness of planning, implementation, and monitoring efforts. As the revised Energy Performance of Buildings Directive (EPBD) strengthens requirements related to new buildings and renovation planning, the implications of these data gaps become increasingly critical for monitoring progress towards a decarbonised building stock.

Many Member States rely on outdated or incomplete datasets that do not always reflect the current state of the building stock, particularly in the non-residential sector, where systematic data collection is largely absent. As a result, incomplete, inconsistent, or poorly governed data represent a direct constraint on credible implementation, undermining the reliability of Energy Performance Certificates (EPCs), reducing the precision of long-term renovation strategies and/or National Building Renovation Plans (NBRPs), and weakening the capacity of public authorities to target support measures effectively.

The Commission’s Staff Working Document that analysed the 2020 long-term national renovation strategies reached the same conclusion: ‘Submissions varied in scope and detail, and the nature of data differed across countries, and in many cases greenhouse gas reduction data were missing, undermining comparability and hampering an EU-level view of cumulative impacts. In practice, Member States continue to struggle to provide all the necessary reporting in a complete and consistent way’.

The implications of data gaps extend beyond technical efficiency. In regions characterised by ageing building stocks, low renovation rates, and high levels of energy poverty, inadequate data can lead to negative and unintended social impacts. Ensuring that renovation policies are both effective and socially fair and proportionate requires a robust evidence base that captures not only energy performance but also building characteristics, renovation costs, and socioeconomic conditions.

Why data gaps matter for EPBD implementation

Data gaps affect the EPBD implementation at multiple levels. At the building level, incomplete or unreliable information undermines the credibility of EPCs and limits their usefulness for owners, tenants, and investors. At the policy level, insufficient or inconsistent data limits the design and targeting of renovation support schemes, making it difficult to reliably identify and prioritise the worst-performing segments of the building stock or to address affordability risks. [A(1] At strategic level, fragmented and inconsistent datasets weaken the evidence base for NBRPs and reduce the robustness of progress monitoring.

Reliable data are also essential for defining and operationalising key EPBD concepts, including Zero Emission Buildings (ZEBs), cost-optimal minimum energy performance requirements, and minimum energy performance standards (MEPS). Without a consistent overview of building characteristics and performance, it is difficult to identify worst-performing segments of the building stock or to calibrate policy measures that balance ambition with feasibility and social fairness.

The absence of high-quality data also limits the ability to assess policy impacts over time. Monitoring renovation rates, energy savings, emission reductions, and social outcomes requires comparable and regularly updated information. Where data are missing or inconsistent, public authorities have difficulty adjusting policies, reallocating resources, or demonstrating progress at the national and EU level.

Recognising these challenges, the revised EPBD emphasises on data governance, transparency, and interoperability as cross-cutting enablers of effective implementation. Article 22 specifically strengthens requirements related to the availability, accessibility, and the reuse of building-related data, underlining the need for coherent data frameworks that support policymaking across governance levels and throughout the building lifecycle.

From fragmented data landscapes to effective, data-driven EPBD implementation

Building-related data are collected primarily for administrative, compliance, or statistical purposes, often without a clear strategy for integration and long-term reuse. Data are dispersed across multiple institutions and stored in disconnected databases based on heterogeneous definitions and formats. As a result, information on building characteristics, energy performance, renovation history, and technical systems remains fragmented and difficult to integrate.

This fragmented data landscape constrains the ability of public authorities to translate EPBD requirements into operational policies. EPCs are frequently produced and stored independently of renovation programmes, funding mechanisms, or social policy instruments. Long-term renovation strategies and NBRPs often rely on aggregated assumptions rather than building-level evidence, while monitoring systems struggle to capture actual renovation progress and realised energy savings.

A shift in governance is therefore required. Building data should be treated as a strategic public asset supporting the full policy cycle, from planning to evaluation. Interoperable frameworks connecting EPC registries, renovation passports, digital building logbooks (DBLs) and statistical databases can improve targeting, enhance policy precision and strengthen impact assessment.

Articles 16 and 22 of the revised EPBD further emphasise controlled and secure access to building data for a wider range of stakeholders. Facilitating access for research organisations, financial institutions and market actors can support innovation, improve risk assessment and mobilise investment, provided that accessibility is balanced with data protection, confidentiality and cybersecurity safeguards.

Improved data integration also strengthens the social and affordability dimensions of EPBD implementation. Linking building-level energy performance data with socioeconomic and housing market indicators enables public authorities to identify vulnerable households, assess affordability risks and understand how renovation requirements interact with housing costs and tenure conditions. This integrated evidence base supports a more proportionate application of renovation obligations and minimum energy performance standards, particularly where energy inefficiency, low incomes and housing pressures coincide. By improving visibility into how renovation measures affect housing costs and living conditions, data integration can help ensure that energy performance improvements contribute to affordable, adequate housing rather than exacerbating displacement or cost burden.
 

_{Figure 1. Indicative expert-based assessment (OBSERVE project) of the current and EPBD-aligned building data ecosystems. Source: OBSERVE project.}
 

Key priorities for bridging data gaps

Experience from Member States, implementation assessments, and policy monitoring exercises points to a set of key priorities that are critical for bridging existing data gaps and supporting the effective implementation of the revised EPBD.

A first priority is the establishment of permanent, multilevel cooperation and coordination mechanisms for building and energy data. In several countries, institutionalised arrangements involving ministries, regulators, statistical authorities and local administrations enable regular data exchange, validation, and cross-checking. For example, centralised EPC registries in France and the Netherlands are linked to national observatories and statistical systems, allowing for consistent aggregation of building performance indicators and improved monitoring of renovation trends. In Spain, coordination between national and regional administrations supports the consolidation of building performance data across autonomous communities, improving comparability and reporting consistency. These mechanisms enable the development of shared assumptions and improve consistency across datasets and reporting cycles. Where such arrangements are absent, data collection often remains fragmented and is mainly activated in response to reporting deadlines, limiting opportunities for quality control and coherence.

A second priority concerns integrated digital information systems and centralised databases. Moving from disconnected registries to interoperable digital platforms with automated data flows and quality control reduces administrative burden, improves reliability and strengthens the production of comparable indicators for monitoring and evaluation.

The development and consistent application of harmonised methodologies and operational procedures represent the third priority. Clear internal methodologies defining data sources, responsibilities, reporting formats, update cycles and quality assurance mechanisms help reduce inconsistencies across reporting periods and improve transparency. When applied systematically, such frameworks strengthen the link between policy measures and the data used to assess effectiveness.

Implementation experience shows that these mechanisms need to operate on a continuous and institutionalised basis. More robust approaches formally define responsibilities, ensure adequate human and technical resources, and embed data management processes within permanent administrative structures, which allows data to be maintained and validated on an ongoing basis rather than through episodic reporting exercises.

In addition, the promotion of transparency and appropriately governed public access to building and energy data is a cross-cutting priority. Making key datasets and indicators publicly available enables scrutiny by researchers, market actors and civil society, supporting accountability and acting as an additional quality check. At the same time, greater transparency entails important trade-offs related to privacy, data protection, cybersecurity and the safeguarding of commercially sensitive information. Building-level data may contain personal or strategic information, particularly when linked to ownership, occupancy or consumption patterns. For this reason, effective data governance frameworks must rely on aggregation, anonymisation and role-based access mechanisms that reconcile openness with legal and security requirements. When carefully designed, such safeguards allow transparency to enhance credibility and trust without compromising individual rights or system security.
 

_{Table 1. Evolution of the building data ecosystem: from silos to interoperability.}
 

The role of energy dataspaces and digital solutions 

Energy dataspaces represent a transformative approach to achieving the data-related objectives of the EPBD by creating a trusted, federated environment for sharing and reusing building energy data across stakeholders. Unlike isolated databases, dataspaces enable interoperability through common standards and semantic frameworks, allowing EPC registries, DBLs, renovation passports, and smart metering data to be connected seamlessly. This integration supports lifecycle monitoring of building performance and is essential for implementing MEPs and progressive renovation trajectories. By ensuring secure, role-based access and compliance with data protection rules, dataspaces empower local authorities, policymakers and service providers to make evidence-based decisions while fostering innovation in areas such as AI-driven renovation planning and predictive maintenance. Ultimately, energy dataspaces provide the backbone for a coherent, transparent and fair data ecosystem that underpins EPBD goals, enabling more effective governance, targeted investment, and measurable progress towards a decarbonised building stock.

In parallel, advanced digital solutions, including digital twins, artificial intelligence and data analytics, can further enhance the usability of building data and support renovation planning and performance monitoring. Their effectiveness, however, depends on the availability of reliable, harmonised data and coherent governance arrangements that ensure transparency, security and trust.

National perspectives and expert insights

Understanding how building-related data are collected, governed and operationalised at national level is essential for assessing how the revised EPBD is translated into practice. While previous sections highlighted structural data challenges, their practical implications differ significantly depending on national institutional frameworks, governance models and levels of digital maturity.

Across the EU, Member States operate under diverse administrative arrangements that shape how EPBD provisions are implemented. Variations in centralisation, data ownership structures, coordination between national and regional authorities, and the integration of EPC systems with renovation funding instruments influence the effectiveness of monitoring, compliance and social targeting mechanisms. These institutional configurations determine not only data quality, but also how renovation strategies are prioritised, financed and evaluated over time. At the same time, national experiences reveal emerging reforms and digital initiatives that demonstrate how governance structures can evolve to better align building data systems with EPBD requirements.

These issues are explored in detail in three Technical Articles that are being published this month in the BUILD UP portal, focusing on the national contexts of Spain, France and Italy. These articles analyse how building data frameworks operate within different institutional and regulatory settings and assess their implications for the implementation of the EPBD. While grounded in specific national experiences, the insights and lessons presented are relevant beyond the countries examined and provide a basis for comparative assessment and mutual learning across Member States.

The Topic of the Month is further developed in two interviews that offer complementary strategic perspectives. Paolo Bertoldi, from the  Joint Research Centre, European Commission, will discuss the policy rationale behind the strengthened data-related provisions of the revised EPBD and clarify how improved data quality, accessibility and harmonisation support credible implementation at EU level. The interview with Eduard Loscos, Chairperson of the Building Digital Twin Association, examines the role of digital twins and advanced data infrastructures in enabling building performance monitoring and renovation decision-making, highlighting their dependence on reliable and interoperable data.

Taken together, the national analyses and expert perspectives underline the importance of knowledge transfer and institutional capacity building. Bridging the data gap requires not only technological solutions but also the ability of public authorities and stakeholders to adopt shared methodologies, reuse tools and standards, and translate experience across different national and institutional contexts.

European initiatives, best practices and projects addressing data challenges

At the EU level, a number of established initiatives support Member States in addressing data-related challenges in the building sector and strengthening alignment with the revised EPBD. A central reference point is the EU Building Stock Observatory (EU BSO), which provides a harmonised framework for monitoring the energy performance of buildings and renovation progress across the EU. By relying on common indicators, definitions and reporting structures, the EU BSO contributes to improved transparency and comparability of national data. With the implementation of Article 22 and the associated implementing regulation, its role is further reinforced, supporting more consistent reporting practices and enhanced data quality across Member States.

Several EU-funded projects complement this framework by focusing on specific aspects of data governance, interoperability and policy implementation. Projects such as OBSERVE support Member States in strengthening national data methodologies, improving alignment with EU reporting requirements, and enhancing the use of building data for renovation planning and monitoring. These efforts directly contribute to addressing structural data gaps identified in the context of the implementation of the EPBD.

The ReLIFE project provides additional insights into how building-level data can support renovation strategies by improving the understanding of building performance, renovation pathways, and implementation barriers. By working closely with national and local stakeholders, ReLIFE contributes to the development and testing of approaches that improve data availability and usability for policy design and decision-making in the building sector.

INDICATE LIFE aims to address one of the biggest challenges in reducing whole life carbon (WLC) emissions of the built environment by improving the life cycle assessment (LCA) data quality and availability of buildings within Europe. Lack of building LCA data is widely understood to be a key obstacle in achieving industry and policy action on WLC.

As a growing number of EU-funded projects target the implementation of the EPBD, discussions are currently underway on the development of a cluster of sister projects focused on building data and digitisation. The objective of this clustering effort is to facilitate structured cooperation among sister projects for data collection, enabling joint activities, and supporting the formulation of common recommendations for policymakers and implementing authorities. Such collaboration can help consolidate evidence, avoid duplication, and enhance the visibility and uptake of project results.

Conclusions

Overall, the implementation of good practices indicates that improvements in the collection, management and use of building data and the automation of related processes are achieved most effectively when the following four enabling conditions are jointly in place:

• Permanent coordination structures enabling continuous cooperation, data exchange and validation among relevant authorities.
• Integrated information systems and centralised databases and observatories supporting interoperability, automation, and reliable data storage.
• Harmonised methodologies and quality assurance procedures ensuring consistency, transparency and comparability over time.
• Transparency and public access to data strengthening accountability, credibility and informed participation.

Taken together, these enabling conditions provide a robust foundation for data-driven renovation planning, effective policy monitoring, and socially fair implementation of the revised EPBD.

Send your contributions to BUILD UP

February’s Topic of the Month in BUILD UP is ‘Bridging the data gap in the building sector for full EPBD implementation’. We welcome contributions from professionals, researchers, local authorities and organisations working to advance energy efficiency in the built environment. Readers are invited to share articles, technical insights, project results, case studies, news, events or training materials that can support the platform’s knowledge base and strengthen collaboration across Europe’s renovation community.

Visit the BUILD UP ‘How to contribute’ page and follow the process.