From Data to Decisions: How Open Building Information
Serves the Public Good
Across Europe, decisions about housing, renovation, and public investment depend on information about how buildings use energy. Yet most of that information remains scattered across national databases or presented in ways that ordinary citizens can barely understand. OpenBEP4EU contributes to solving this by developing open, comparable methods for Energy Performance Certificates (EPCs) and the Smart Readiness Indicator (SRI). The aim is to make all the building data we already collect more usable.
Open building data begin with clear technical definitions. OpenBEP4EU uses the CEN/ISO 52000 family of Energy Performance of Buildings (EPB) standards, developed for gradually underpinning the national Energy Performance calculation methods. Turning those standards into open-source code makes their logic visible, testable, and reusable. That transparency lets authorities and researchers trace how results are generated, which hopefully leads to more consistent and dependable results over time.
Citizens and Local Governments
as Users, Not Just Recipients
For many people, a building certificate only appears when buying or renting a home. But aggregated EPC and SRI data can do much more. Municipalities could use open data to map areas where homes lose the most heat and direct renovation support there first. Whereas a housing association might compare EPC data to prioritise which buildings need more insulation. And a university could study whether new technologies actually improve energy performance over time. So, public access to building data helps citizens see whether renovation efforts are working where they live, and it gives municipalities evidence to plan more fairly. In that way, open data actually link large climate goals with daily realities such as housing comfort, health and wellbeing, energy bills, and public spending.
How can open-source design make national EPC and SRI systems easier to connect and maintain over time?
Open-source design, both in terms of software and APIs facilitate connection and maintenance of the relevant systems by making them more future-proof, transparent, interoperable and evolving digital solutions rather than closed and isolated IT components. The use of common data models and communication methods ensure that all national registries, assessment tools and reporting platforms “speak the same language” leading to straightforward exchange, aggregation and comparison of EPC and SRI information.
Additionally, publishing interfaces and implementations openly removed dependency on a single vendor or proprietary system leading to wider adoption. Another benefit is the transparency in how the EPC and SRI calculations are performed, making it easier to verify regulatory compliance and ensure consistent results over time, as well as allow to apply updates and changes –regulatory or methodological- once and apply them across different systems, without the need of duplicate maintenance effort.
The use of open APIs makes the systems to be built with modular components, and enable easier upgrades, by applying changes only to affected elements and without disruptions in entire systems, making long-term maintenance more predictable and cost-effective.
Lastly, open-source allows industry, public authorities and research organisations to collectively maintain and improve EPC and SRI software, hence reducing technical debt, increasing resilience and ensuring that systems remain operational and updated long after the initial procurement funding ends.
Why Open Building Data Matter
When information stays in separate systems, it becomes difficult to coordinate renovation support or assess how EU funds are spent, but the revised Energy Performance of Buildings Directive (EU 2024/1275) supports a shift toward openness through the Common European Energy Data Space, a secure framework for sharing anonymised building data across Member States.
Key frameworks
behind open building data
- Energy Performance of Buildings Directive (EU 2024/1275) defines EPC and SRI rules, data exchange and EPB databases vis-a-vis the EU Building Stock Observatory (BSO)
- Data Act (EU 2023/2854) establishes rights for sharing and reuse of non-personal data
- Common European Energy Data Space links national systems through common standards
What role does transparent, standardised calculation frameworks play in ensuring the credibility of EPCs and the SRI?
Credibility in EPCs and SRI comes from one simple principle: anyone should be able to understand how a rating was produced and reproduce it from the same inputs. Transparent, standardised calculation frameworks, like the CEN/ISO EPB standards, make that possible by defining clear technical concepts, calculation steps, and national parameter choices in a structured way. When those rules are implemented as open, testable code, the methodology stops being a matter of interpretation and becomes something you can verify. That strengthens quality assurance, supports consistent training and accreditation, and makes it easier to detect anomalies across large datasets. It also improves comparability between Member States, which is essential when EPC and SRI data are used to steer renovation funding and track progress under the EPBD. Ultimately, transparency doesn’t just build trust in EPCs and the SRI, it builds trust in the policies and investments that rely on them.
Why This Approach Matters
Europe’s renovation and housing targets rely on evidence that is consistent and fair. Without comparable data, governments cannot know whether subsidies reach the right buildings or whether energy savings are real. With open, harmonised building data, those decisions become clearer. For citizens, that means better visibility into how public funds are used and what progress is made locally. For governments, it means decisions based on shared facts rather than isolated reports. Openness makes more participation possible and hopefully support a fairer transition.
Keeping Open Data Safe
Without shared access, information remains fragmented. Each country or region measures building performance differently, making EU-wide comparisons unreliable. Renovation funding risks going to areas with more generous assessment methods rather than to those with the greatest need. And smaller municipalities have to commission new studies instead of just using existing data, and furthermore, citizens cannot easily verify how their public renovation money is spent. Which means, that closed systems may keep some information safer, but unfortunately also keep people out of the process.
Opening building data does not mean revealing private details. Before information is shared, personal or location identifiers are removed, and results are grouped by area rather than by individual buildings. The Data Act ensures that data collected for public purposes remain available for the public good, while the General Data Protection Regulation (GDPR) protects personal privacy. Together, these rules make it possible to use building data for planning and renovation without exposing anyone’s personal information.
How can accessible EPC and SRI data help municipalities plan fairer renovation programmes for citizens?
For municipalities, reliable EPC data can support planning and portfolio management. Local authorities are responsible for many public buildings with different ages, uses, and renovation needs. Comparable EPC data make it possible to establish a consistent baseline across that portfolio and to prioritise renovation measures in a structured way.
In practice, EPCs can help municipalities decide when renovations should take place, which measures can be combined, and how investments align with long-term operation and maintenance plans. Consistent data also support applications for green loans and public funding, where authorities must justify choices over several budget cycles. While EPCs remain a static assessment, their value for municipalities lies in comparability and traceability, enabling more coherent planning of public building renovations over time.
Whereas closed data systems are removed from the public,
making data accessible introduces its own challenges
- Privacy Even anonymised datasets can sometimes reveal details in small communities. This can be managed by grouping data and removing direct identifiers (Street address will be replaced by, e.g. “Residential Building, District 3”; owner or tenant names could be replaced by “Private ownership”; property registration number could be replaced by broad classifications like residential, public school, multi-family housing, office, etc.).
- Misinterpretation Without context, people might read raw data incorrectly. Providing plain-language explanations and metadata helps avoid this.
- Unequal access Some local authorities may not have the tools to analyse large datasets. EU programmes now include training and support to bridge that gap.
- Cybersecurity Opening data systems creates new digital gateways. Following ENISA’s cybersecurity guidance ensures protection through encryption, access control, and monitoring.