The D^2EPC Vision

D^2EPC aspires to deliver the next-generation of dynamic EPCs for the operational and regular assessment of buildings energy performance through a set of cutting-edge digital design and monitoring tools and services. D^2EPC relies upon and adjusts accordingly to the smart-readiness level of the buildings and the corresponding data collection infrastructure and management systems. It subsequently builds upon actual data and the ‘digital twin’ concept to calculate energy, environmental, financial and human comfort indicators and through them the EPC classification of the building in question. The project focuses on delivering an intelligent, interoperable, and user-friendly platform that enhances transparency, encourages behavioural change, and supports informed investment decisions. At its core, D^2EPC promotes a continuous certification process based on real consumption and performance metrics.

Enabling Smart Digitalisation: The Role of BIM and IoT

A fundamental innovation of the D^2EPC platform lies in its ability to harness data from Building Information Models (BIM) and Internet of Things (IoT) devices to construct and maintain digital twins of buildings. These digital replicas continuously reflect the physical building's status, capturing real-time operational data and structured information from BIM files. The integration of BIM enables the platform to model a building’s geometry, components, systems, and intended use in a highly structured way. BIM data serves as a digital repository for design specifications, material properties, and system configurations. Through the platform’s automated IFC parser, relevant information is extracted, semantically interpreted, and mapped to support asset rating calculations, renovation planning, and SRI assessments.

Complementing this, the IoT layer of the platform enables dynamic data collection from smart meters, sensors, and building management systems. It provides continuous streams of high-resolution data on energy consumption, temperature, humidity, and indoor air quality. This real-time feedback is essential for operational rating, comfort assessment, and predictive analytics, ensuring that the building’s performance is monitored under actual operating conditions.

By merging static design data with live performance insights in a central data structure, digital twins serve as the foundation for a holistic and dynamic certification scheme, enabling the continuous evaluation of building performance. In this way, building certification is no longer static, but a living representation of the building’s real energy behaviour, smart readiness, and indoor environmental quality.

Key Services of the D^2EPC Digital Platform

The D^2EPC digital platform serves as the central interface for implementing the dynamic energy certification scheme and interacting with the full range of tools developed within the project. Designed to support building end-users (tenants, owners, facility managers), as well as building professionals (engineers, EPC assessors) and  public authorities, the platform offers a suite of integrated services that combine real-time monitoring, certification issuance and performance analytics.

Figure 1 Key Services of the D^2EPC Digital Platform

The D^2EPC platform offers advanced monitoring capabilities, allowing users to access live data streams from integrated IoT devices installed throughout the building, such as temperature measurements, energy use, air quality, and occupancy. In parallel, the platform provides a fully interactive 3D digital model of the building, enabling users to navigate its structure and access detailed information on individual building elements. This information is dynamically sourced from both the original BIM files and the updated digital representation within the platform, offering a comprehensive and current view of the building’s condition and performance.

Figure 2 D^2EPC platform interface illustrating the BIM-based digital twin

Energy Performance Certification as the cornerstone of the D^2EPC framework

At the heart of the D^2EPC platform lies a hybrid Energy Performance Certification scheme which aims to capture the full energy profile of a building via two rating schemes:

• Asset Rating reflects the theoretical energy performance of a building based on its design characteristics, construction elements, and building systems, following standardised conditions. It is primarily calculated through simulation models aligned with EN ISO 52000:2017 series standards and draws on nationally adapted datasets for climate, energy carriers, and typical user behaviour. The asset rating is useful for comparing buildings under consistent conditions and serves as a baseline for regulatory compliance and renovation planning.
• Operational Rating represents the actual measured energy consumption and CO₂ emissions during the building's use phase. It is based on data collected through smart meters, sensors, and building management systems, capturing real-world user  behaviour and building operation. This dynamic rating is updated regularly and provides actionable insights into performance gaps and user impacts. Combined these two ratings offer a comprehensive diagnosis of a building’s performance, highlighting the gap between design expectations and actual usage, which will enable the development of more informed energy efficiency strategies.

Figure 3 Visual comparison of asset-based and operational-based energy ratings using the D^2EPC platform

Beyond Energy: Introducing Innovative Performance Indicators

To address the multifaceted nature of building performance, D^2EPC introduces a comprehensive set of indicators that extend beyond traditional energy consumption metrics:

• Smart Readiness Indicator (SRI): This scheme assesses a building’s capacity to adapt to occupant needs and interact with the energy grid through smart technologies. The indicators encompass systems such as heating, cooling, ventilation, lighting, EV charging, and building automation. The D^2EPC approach is fully aligned with the most up-to-date EU calculation framework for SRI assessment, ensuring methodological consistency with ongoing regulatory developments
• Environmental Indicators: Based on Life Cycle Assessment (LCA) methodologies, these indicators quantify the environmental impact of buildings throughout their life cycle, including embodied emissions from materials, construction, and end-of-life phases.  The approach is aligned with the EU Level(s) framework, ensuring consistency with common performance indicators for sustainable buildings.
• Financial Indicators: This set of indicators is related to  cost and economic indicators based on the well-established concept of whole life cycle costing (LCC) ,  enabling the interpretation of the individual elements of a building’s energy performance into normalized monetary values and assisting  .
• Comfort and Wellbeing Metrics: Designed to assess indoor environmental quality, these metrics include thermal comfort (temperature and humidity ranges), visual comfort (illuminance levels), and indoor air quality (CO2, VOCs, PM2.5). The indicators are based on standards such as EN 15251 and are partly derived from real-time sensor data.

Figure 4 Visualization of multidimensional building performance indicators within the D²EPC platform

Advanced Intelligence Features

At its higher level, the  D^2EPC platform extends beyond certification by offering a set of added value services by leveraging cutting-edge technologies from the areas of IoT, AI and the general field of ICT for the provision of the optimal recommendations for performance upgrade, calculation of energy performance predictions, issuance of performance alerts and notifications and benchmarking of buildings’ energy performance. The tools support predictive maintenance and allow users to optimize energy usage, making the system fully aligned with Industry 4.0 principles—automation, interoperability, and intelligent performance optimization. With the following set of features stakeholders are empowered to take proactive actions and  optimise building performance throughout its lifecycle:

• AI-Driven Performance Forecasts: The D^2EPC platform integrates artificial intelligence algorithms to predict future building performance based on historical data and operational patterns. This feature supports proactive decision-making and long-term planning for energy efficiency improvements.
• Renovation Roadmapping: This tool supports the creation of  personalised renovation roadmaps. By taking into consideration the building’s current performance, user-defined goals and related building regulations, the tool suggests a stepwise set of upgrade scenarios over a defined timeline. These roadmaps incorporate technical, financial, and environmental considerations, helping stakeholders  prioritise interventions and plan long-term investments towards  decarbonisation and improved energy efficiency. This functionality contributes to the generation of structured Building Renovation Passports in line with emerging EU policy frameworks.
• Performance Alerts and Notifications: Users receive automated alerts when specific performance thresholds are exceeded or when anomalies are detected in the building’s operation. This functionality enhances responsiveness and supports preventive maintenance.
• Building Energy Performance Benchmarking: D^2EPC enables users to benchmark buildings against a range of criteria, such as type, usage, climate zone, or national averages. This helps identify underperforming assets and prioritize renovation efforts, as well as facilitate urban planning and decision making for local and regional authorities.
• WebGIS Visualisation Engine: Offers interactive, geospatial mapping of EPCs across different regions. Users can perform spatial queries, visualize certification density, and access comparative statistics—an essential tool for public authorities and AEC stakeholders enabling not only to map and monitor building stock, but also quantify energy demand, examine the energy sources used in a building, and launch investment strategies to enhance the share of renewables.

Figure 5 Overview of the D²EPC platform’s analytics and planning capabilities

Real-world application: Demonstrating impact

Six pilot buildings across Europe (including Greece, Cyprus, and Germany) served as real-life testing grounds for the D^2EPC framework. These pilots represent diverse building types and climates, validating the robustness of the platform's data ingestion, rating methodologies, and visualisation tools. The  evaluation and impact assessment activities targeting different stakeholders (EPC assessors, building owners/ tenants and facility managers) in partner countries (Greece, Austria, Netherlands, Cyprus, Germany), revealed the effectiveness and acceptance of the platform. Considering interactive features, innovation in building sector and platform extensions (enhanced decision making, road-mapping tool) these improvements were highly accepted by EPC accessors at the total rate of 84.92% while based on the same criteria, and with the additional evaluation of the user interface of the intelligent EPC platform, the end-users of the buildings also gave very positive feedback to the platform, with a calculated acceptance rate of 85.71%.

Conclusions

In the transformation towards sustainability, Europe's commitment extends to the built environment. D^2EPC digital platform builds upon the need for buildings’ stock decarbonisation and sets out a dynamic strategy to strengthen EPC in order to promote building performance improvements and have a crucial role towards the green transition. One of the main achievement and legacy of the project related to the update of EU standards is the creation of the CEN / TC 371 / WG5 working group on the 'Operational Rating of Energy Performance of Buildings', aiming to formalize methodologies at the European standardization level.  In this context, the project won the 2023 edition of the CEN and CENELEC Standards + Innovation Awards in the category “Project award” during the event "EU knowledge valorisation stakeholder event: Making research results work for society", hosted by the European Commission.