One common data format for Smarter Buildings Assessments

Keywords: EPBD 2024; iEPB format; Energy Performance Certificate; Smart Readiness Indicator; renovation passport; digital building logbook; life-cycle GWP; gbXML; building data exchange; interoperability; data space.

The EPBD 2024 makes building performance assessment broader, more digital and more connected. EPCs, smart readiness assessments, renovation passports and life-cycle indicators will increasingly need to exchange consistent building data. The iEPB format provides a practical interoperability layer, already tested in SRI2MARKET and national EPC tools. The iEPB Web Application is a powerful dataspace that standardizes data exchange within the iEPB framework, enabling seamless access to vital information across different stakeholders and assessment types.

Why the EPBD 2024 changes the data challenge

The 2024 recast of the Energy Performance of Buildings Directive changes the way building performance information should be understood and managed. Energy Performance Certificates remain a central instrument, but they are no longer the only digital object around which building assessment is organised. The Directive strengthens the role of renovation planning, smart readiness, technical building systems, building automation and control, life-cycle global warming potential, inspections, national databases and digital building logbooks.

For practitioners, this creates a very concrete challenge. The same building may be assessed for its energy performance, its smart readiness, its renovation pathway and its life-cycle climate impact. Each assessment may use different software, different data structures and different national procedures. However, many of the inputs are partly shared: building identification, geometry, envelope properties, technical building systems, energy carriers, automation levels, control strategies and recommendations.

Without a common exchange approach, this information is repeatedly entered, reinterpreted and stored in separate tools. This increases the workload for assessors, makes quality control more difficult and limits the reuse of valuable data by building owners, authorities and software providers. The digital challenge of EPBD implementation is therefore not only to calculate better indicators, but also to ensure that building performance data can move reliably between tools and workflows.

Figure 1. EPBD 2024 assessment instruments and shared building data needs.

From harmonised policy to interoperable tools

The EPBD provides a common European framework, but Member States continue to use national calculation methods, national EPC software ecosystems and national implementation procedures. This is necessary because building regulations, climate data, default assumptions, primary energy factors and certification schemes differ across countries.

For this reason, interoperability should not be confused with imposing a single European calculation engine. A more practical approach is to support convergence at data level. This means that building inputs, assessment outputs, assumptions and recommendations can be described in a common, structured and machine-readable way, while national calculation procedures remain in place.

This is the role proposed for the iEPB format. The challenge is not to replace national EPC tools, but to allow them to exchange building performance data with other EPBD-related instruments. In practical terms, this means helping an EPC tool, an SRI assessment platform, a renovation passport workflow or a future digital building logbook understand the same building information without bespoke one-to-one integrations for every pair of tools.

This data-level convergence is especially relevant for professionals. Assessors and engineers do not need another abstract data model; they need a way to reduce duplication, improve traceability and avoid inconsistent data entry. Authorities need reliable information flows to support databases, quality checks and policy monitoring. Software developers need clear rules to implement import and export functions in real tools.

Figure 2. Structure of the iEPB file: gbXML, iEPB.xml, ILCD and Source.

Implementation in national EPC tools

The value of a common data format depends on its implementation in real tools. For this reason, the iEPB schema is being tested with national EPC-related software, including CE3X in Spain and Ecotech in Austria and Uniec3 in The Netherlands[MS1] . These examples are particularly useful because they show how national procedures can be connected to a common structure without changing the national assessment method itself.

The implementation process requires detailed data mapping. Administrative information, building identification, climate data, geometry, envelope description, thermal bridges, systems, energy carriers and calculation outputs must be analysed and assigned to the appropriate part of the iEPB structure (Figure 2). Some data can be stored in gbXML. Other data must be placed in the iEPB.xml file, either because they are tool-specific, country-specific or assessment-specific.

This mapping exercise is not a minor technical detail. It is one of the most important lessons from implementation. National EPC tools contain information that has been shaped by regulation, professional practice and software history. A common exchange format must respect this reality. If it is too generic, it will lose essential information. If it is too rigid, it will be difficult for different countries and tools to adopt.

As can be seen in Figure 3, all common Building Energy Model (BEM) information is stored in gbXML, Additional information required at national level is organized in a country block within iEPB.xml, including a common national section for shared building data not covered by gbXML, an EPC block, certification-tool-specific blocks and an SRI block. This preserves interoperability while accommodating national and tool-specific requirements.

Figure 3. Mapping EPC tool data into the iEPB structure.

For assessors, successful import and export can reduce repeated data entry and improve consistency when a building is assessed more than once or through more than one instrument. For software developers, the iEPB format provides a common target for interoperability. For authorities, it creates the basis for more structured, traceable and reusable data flows.

SRI2MARKET: bringing smart readiness into the same ecosystem

The Smart Readiness Indicator adds a complementary perspective to EPCs. While EPCs focus mainly on energy performance, the SRI assesses the capability of a building or building unit to optimise energy performance, adapt operation to occupant needs and respond to signals from the grid. This requires information about technical domains, smart-ready services and functionality levels.

Part of this information overlaps with EPC and technical building system descriptions. Heating, cooling, domestic hot water, ventilation, lighting, electricity, electric vehicle charging, dynamic envelope and monitoring and control are all domains where building systems and controls need to be described consistently. Treating the SRI as a completely isolated workflow would therefore miss an important opportunity for data reuse.

SRI2MARKET provides a practical case for connecting smart readiness assessment to the wider EPBD data ecosystem based on the iEPB format. The platform supports SRI assessment through an online tool (https://sri2market.eu/) and has been used in the Spanish official SRI testing phase. The implementation of iEPB import and export in SRI2MARKET (Figure 4) shows how SRI assessment data can be exchanged with other tools and potentially reused in future EPC, renovation passport, database or digital building logbook workflows.

This is particularly relevant for future implementation. If SRI assessments are to be scaled up, they should not impose unnecessary additional data burden on assessors or building owners. Connecting SRI data with existing EPC and building system information can make the process more efficient, improve consistency and support better quality assurance.

Figure 4. Connecting SRI2MARKET to the EPBD data ecosystem through iEPB.

Lessons learned for EPBD implementation

The implementation work carried out so far provides several lessons for practitioners, authorities and software developers.

First, interoperability must be designed together with real software workflows. A schema that looks complete on paper may still fail if it does not reflect how assessors enter information, how software tools structure projects or how national procedures define mandatory fields.

Second, a common format is useful only if it respects national methods and tool-specific data needs. The objective is not to erase national differences, but to make them explicit and manageable within a common structure.

Third, mapping building systems is as important as mapping calculation results. The EPBD 2024 gives a stronger role to technical building systems, automation, controls, smart readiness and system efficiency. This means that interoperable assessment files must describe not only the building envelope and final indicators, but also the systems and services that determine real performance.

Fourth, quality assurance and version control are essential. If data are reused across assessments, it must be clear where the data came from, which assessment generated them, which version of the building they describe and whether they have been modified. Reusable data are valuable only when they are reliable and traceable.

Finally, EPC, SRI and renovation passport workflows should be connected wherever possible. A building owner should not need to pay several times for the same basic information to be collected. An assessor should not need to recreate building data from scratch when a previous assessment already exists. A public authority should not need to manage fragmented datasets that describe the same building in incompatible ways.

Table 1. EPBD 2024 requirement, data challenge and iEPB response.

Outlook: from assessment files to building dataspaces

The next phase of EPBD implementation will depend not only on calculation methods, but also on the capacity to exchange reliable data between tools, authorities and market actors. EPCs, SRI assessments, renovation passports, life-cycle indicators and digital building logbooks will be more useful if they are connected through consistent data flows.

The iEPB format offers a pragmatic route from fragmented assessment tools to connected building performance information. Its implementation in SRI2MARKET and national EPC tools shows how the EPBD 2024 data challenge can be addressed through interoperable, reusable and software-ready assessment files.

In this sense, iEPB format should be understood as an enabling layer for practical EPBD implementation. It does not replace national tools, national procedures or professional judgement. It helps them communicate. That may become one of the key conditions for turning the broader ambition of the EPBD 2024 into usable, reliable and actionable building performance information.

The iEPB's proposed format, in conjunction with the iEPB Web App, creates a dataspace for managing building energy performance data. This approach provides:

·         Secure Storage: Robust access control and security measures to safeguard sensitive data like tenant information.

·         Data Reusability: The common data model streamlines data reuse across assessments and countries, enhancing efficiency.

·         Collaboration & Interoperability: A unified platform facilitates collaboration between stakeholders with diverse roles (owners, developers, authorities) through their respective interfaces, fostering efficient energy performance practices.