By Gioia Salvatori

Windows? Better with double glazing and top energy ratings — but pay attention to the air gap and the type of glass. Heating and cooling? Reversible systems are often recommended, but which one should you choose? For insulation, is hemp better than glass wool? For many owners of small homes, renovation can feel like a nightmare: calling technicians, navigating conflicting advice, comparing certificates and getting lost in a maze of kilowatt-hours, digital documents, energy labels, obscure acronyms and too much information that is often inconsistent.

Yet the challenge goes far beyond households. At European level, the path towards zero-emission buildings applying the EPBD (Energy Performance of Buildings Directive) is also highly complex. Different countries collect and store data in different ways, speak different regulatory languages and follow different policy models. From Finland to Greece, how can Europe deliver a renovation strategy that is coherent, effective and inclusive?

The urgency has grown sharper in an unpredictable geopolitical environment where energy supply has been threatened by major international crises, from Ukraine to Iran. When energy prices rise, the first to suffer are often the most vulnerable households, those whose purchasing power is already eroded by high bills because they live in inefficient homes they cannot afford to renovate.

Breaking the vicious circle of energy poverty

“My research, together with colleagues in projects such as EDRC, JUST, RENOVERTY, ASSERT and many others, shows that energy inefficiency disproportionately affects low income and socially marginalised groups, ” says Stefan Bouzarovski, co-founded of the European Union Energy Poverty Observatory, and Professor of Geography at the University of Manchester. “However, challenges vary across Europe, and within countries, regions and cities. In Southern and Eastern Europe, energy poverty is often linked to poorly insulated multi apartment buildings and high cooling or heating needs relative to incomes, for example in Greece or Bulgaria. In north-west Europe, the issue disproportionately affects low income tenants, ethnic minorities, people with disabilities and older people living in low quality housing, such as privately rented homes in the UK or rural housing in France. Across all regions, single-parent households, pensioners and people with low incomes face some of the highest risks”.

According to the EU definition, energy poverty occurs when a household must reduce its energy consumption to a degree that negatively affects health and wellbeing. It remains difficult to measure precisely, but for Eurostat, it affected 9.2% of Europeans in 2024.

The same households struggling to heat their homes in winter often struggle to keep them cool in summer. Renovation and energy efficiency are the clearest long-term solutions. But costs remain a major obstacle for low income people, while labour shortages, inflation and bureaucratic hurdles slow progress for everyone.

Europe’s building data problem

At the centre of Europe’s renovation drive sits the EPC (Energy Performance Certificate), the document used to rate how energy-efficient a building is, typically grading homes and offices according to their consumption, emissions and insulation performance. It is often the first reference point for buyers, tenants, owners and policymakers.

But when it comes to EPCs, Europe can resemble a giant Babel: while all Member States operate under a common EU framework, each country applies its own methodologies and administrative systems. Data may be stored in public, private or mixed platforms. File formats vary, indicators differ and calculation methods are not aligned. This fragmentation complicates EU-wide governance and weakens trust among citizens and market actors.

A common language for all

The European project iEPB aims to create a unique and shared data model (schema) for the EPBD. The goal is to enhance the energy performance of the EU’s building stock by boosting synchronisation among existing EPCs and other instruments such as the Smart Readiness Indicator (SRI), the Building Renovation Passport and energy renovation recommendations.

Their aim is to reduce duplication between EPCs, the SRI, renovation recommendations and other tools that currently operate in silos. “The goal of the project is not to provide a common EPC since each country has its own governance and regulatory context. We have a more practical aim: make them speak the same language”, Eva Lucas Segarra, architect at https://www.five.es/Instituto Valenciano de la Edificación and project coordinator, says.

At this stage of the project, their common data model is already available and has been implemented in several national EPB software tools across the pilot countries, in Austria and Spain, while work in the Netherlands is still ongoing.

A standalone SRI application has also been developed as a calculation engine, making it much easier for other software tools to integrate and run Smart Readiness Indicator assessments. In this wider Babel of data, iEPB is effectively providing both a calculator and a translator, helping organise information within a common framework.

Lucas Segarra explains: “An EPC tells you how the building performs, an SRI tells you how ready it is to operate in a smart way, and a Renovation Passport helps you plan improvements step by step – iEPB tries to make sure they are not speaking different languages”.

From data model to practical tool: an all-in-one web application

At the centre of the project is a web application designed to give users access to the best possible building information with minimal effort – where different assessments from different tools or countries can be brought together

The platform is primarily intended for owners, technicians, administrators and potentially public authorities. The web app has been designed with different user profiles and permission levels in mind, depending on what each actor needs to see or do. For example, building owners can grant temporary access to other users, such as prospective buyers or renters, so that they can consult relevant building documents. The precise deployment model for wider future use is still being designed.

“The web application is presented as a neutral playground where different assessments from different tools or countries can be brought together, allowing access to information for different types of users while taking into account the constraints and necessities of each one, ” explains Miguel Ángel Pascual Buisán, CEO of Efinovatic, partner in the project. “This frees up time for users to focus on analysing the best solutions rather than gathering information”.

Technical and political challenges

Building such a system, however, is far from straightforward. The three pilot countries, Spain, Austria and the Netherlands, have helped expose the practical difficulties of making interoperability work in real life. “The main challenge in the project is technical – Lucas Segarra underlines – it is the complexity of turning this common data model into something real and practical in different contexts. As we implement it in the web app, carry out internal testing and prepare the pilot phase in the three countries, we are identifying issues that require further refinements and adjustments”.

Despite those obstacles, the web application is promising. For example, it could streamline assessments by allowing professionals to complete an SRI more easily while carrying out a mandatory EPC.

What policies are needed to scale

Beyond the technical side, project experts argue that Europe also needs a clearer policy framework if renovation is to scale up (and scaling is fundamental to contrast energy poverty).

“The policy direction we support is threefold: first, common and open data models that make coordination possible; second, implementation guidance that is practical not only conceptual; and third, digital infrastructures that allow trusted data exchange between assessment tools, national databases and, where appropriate, private sources”, Lucas Segarra states. “If we want renovation to scale up, assessments must become more coherent, more useful, less repetitive and easier to carry out”, she adds.

Scale is a key issue in the fight against energy poverty. Europe has already made progress through regulation such as the EPBD and through public funding, but major barriers remain.

Stefan Bouzarovski warns: “Fragmented policy implementation, inadequate recognition, unstable funding and uneven government capacity, slow down progress”. He is equally cautious about overestimating the role of artificial intelligence. “Without adequate frontline support and engaged delivery mechanisms, digital tools risk reinforcing existing inequalities rather than transforming the renovation wave”.

For further information about iEPB and its objectives, please visit https://iepb-project.eu/