Results

The crossCert project addressed key technical aspects of EPC methodologies, including calculation inputs and outputs, KPIs, performance gap, renovation measures, and quality verification methods to provide possible improvement  suggestions for future EPCs and highlight the difficulties in achieving harmonisation across Europe. This is further informed by the L, C and P cross tests carried (Gómez and Fueyo, 2022), studying the differences in methodologies. The comparisons summarised  show that the EPC methodologies use various degrees of standardisation in their calculation approach and can be categorised based on this criterion.

Similar to the considerable variations between EPC assessments across countries, there are differences between the countries’ current approaches to quality control mechanisms for EPCs. Comparing these mechanisms allows for a  iscussion around best practice approaches towards a harmonised  framework. The path towards next-generation EPC metrics requires guidance, particularly around the limits of harmonisation. Further to enhanced quality controls, the introduction of more dynamic KPIs in next-generation EPCs, such as real-time  energy use and lifecycle environmental impact, will provide more actionable insights for the users. Harmonisation of KPIs across countries is essential to make EPCs comparable and effective in driving building decarbonization.

The next-generation EPCs have significant potential to improve their usefulness. A detailed analysis of current EPCs in target countries is paired with research into how they can be integrated into national databases and renovation one-stop shops, while leveraging tools such as energy audits, building logbooks, and renovation passports. This can help end-users and investors fully grasp the benefits of building renovations. In addition to improving user-friendliness, a digital EPC format offers significant benefits for potential investors. These include access to up-to-date, dynamic data that more accurately reflect real conditions, compared to outdated, static paper formats. Integrated databases within  certification tools provide valuable support to EPC issuers.

Energy audits, building logbooks and building renovation passports integration with EPCs enables access to valuable data. The availability of clear, accessible information on buildings and renovation measures is crucial for end-users deciding whether to rent, buy, or renovate properties. Building Renovation Passports (BRPs) and Logbooks, serve as central tools for storing this information. These tools enable users to plan and monitor building renovations toward achieving zero-energy status.The integration of EPCs with energy audits, Logbooks, and BRPs faces obstacles, particularly regarding data privacy, interoperability, and stakeholder coordination. Ensuring secure data exchange and standardising systems across countries is vital.

High readiness of next-generation EPC schemes for integration with one-stop shops in some crossCert countries can be observed. One-stop shops have gained increased prominence in the EPBD as key resources for renovation
information and advice, with a dedicated article outlining their role. Research on the one-stop shops developed and operational in crossCert countries has explored how future EPCs can support these platforms. The aim is to accelerate building upgrades and increase renovation rates. The analysis shows that 88% of the one-stop shops have a holistic approach and are verified by relevant authorities.

Across Europe, EPCs are typically seen as drivers for building renovation and energy performance improvement. However, research shows that many perceive EPCs as merely an “administrative necessity“ with little value, a view shared by both construction experts and property owners (Bančič and Vetršek 2022). To address this, crossCert promotes a people-centred approach to EPCs, focusing on three key areas for improvement: user experience, system optimisation, and public perception. A key issue is the disproportionate focus on technical, methodological, and policy aspects, while the people behind the system—EPC assessors, support networks, and users—are treated as secondary. Our approach to people-centred EPC products and services takes the opposite view: it places people at the core, with technical aspects like calculation methods seen as secondary. Policies shape everyday experiences through the interplay of materials, skills, and meanings, which are constantly shaped by interactions among stakeholders. To improve EPC systems, it is essential to understand these dynamics—social networks, trust, power, perceived value, media influence, and social justice.

The status quo of harmonisation in EPC ratings through cross testing: The crossCert project involved extensive cross-testing of various European countries‘ methodologies for Energy Performance Certificates (EPCs) to explore  discrepancies, harmonise procedures, and learn from best practices. The project was structured around two key tests: C-building testing (comparing methodologies across similar climates) and L-building testing (local assessments focusing on performance gaps). The testing aimed to assess the feasibility of harmonising EPC processes across Europe by highlighting differences in calculation methods, data use, and the role of default values.