Platform architecture
Retabit is a data-centric platform that facilitates the integration of building renovation into broader urban regeneration strategies by combining energy, economic, and social indicators within a unified system. Drawing from public data sources, it supports municipalities with actionable insights that link renovation projects to wider climate and urban transformation agendas.
The data from various public sources in Catalonia, spanning multiple domains such as cadastres, censuses, energy performance, and geospatial data are integrated in the platform. This data serves as the foundation for a series of indicators that capture building characteristics within the broader context of their urban environment, social dynamics, and economic condition.
Data integration
The Retabit platform uses a robust, data-driven approach to support informed decision-making. It integrates 11 core datasets, totaling over 15 million records, covering buildings, infrastructure, energy performance, environmental factors, and socio-economic indicators (see Table 1).
| Data sources | Scale | Domain | Provider | Num. of registers |
|---|---|---|---|---|
| Cadastre - buildings | Building | Other | Ministry of Finance, Spain | 1,396,004 |
| Cadastre - properties | Building | Other | Spanish Ministry of Finance, Spain | 6,742,293 |
| Road networks | Urban | Other | National Geographic Institute, Spain | 1,147,000 |
| Habitability certificates | Dwelling | Other | Department of Territory, Housing and Ecological Transition, Spain | 3,058,727 |
| Energy Performance Certificates | Building | Energy | ICAEN, Government of Catalonia | 1,322,334 |
| Climatic Atlas cartography | Urban | Environmental | Department of Agriculture, Livestock, Fisheries and Food, Government of Catalonia | 179 |
| Open Street maps (equipment) | Building | Environmental | ©OpenStreetMap Contributors | 31,874 |
| Land cover map | Urban | Environmental | Cartographic and Geological Institute of Catalonia | 1,526,984 |
| Digital elevation model | Urban | Environmental | Cartographic and Geological Institute of Catalonia | 267 |
| National housing rental reference system | Census tract | Socio-economic | Ministry of Housing and Urban Agenda, Spain | 5,081 |
| Annual population census 2021-2024 | Census tract | Socio-economic | National Institute of Statistics, Spain | 36,334 |
Data is regularly collected from reliable sources like national cadastral records, energy certificates, and census data, using an automated Extract-Transform-Load (ETL) pipeline built in Java and Python. During processing, data is cleaned, harmonised, and spatially aligned using the ETRS89-UTM31N coordinate system, ensuring consistency across layers.
The system maintains strict relational integrity in a PostgreSQL/PostGIS database and serves geospatial layers via GeoServer with full interoperability for GIS and BIM applications.
The platform also enriches building data with geometric descriptors and uses machine learning (XGBoost) to impute missing values with high accuracy (R² > 0.85). The entire workflow is open-source, version-controlled, and fully auditable, ensuring transparency and reproducibility.
Multidimensional indicators
A systematic review of academic and grey literature identified relevant local and regional studies, with eight detailed case studies (e.g. Barcelona, Los Angeles) selected for comparison. Indicators from these cases were cross-checked against the Sustainable Development Goals (SDGs) to ensure relevance, multi-target alignment, connection to Sustainable Energy and Climate Action Plans (SECAPs), applicability to residential renovation, and availability of open, fine-scale data.
Out of 745 initial indicators, 114 met these criteria, and a harmonised set of 16 building-level indicators were identified, in three domains:
Energy
Near-zero energy buildings.
This indicator identifies buildings classified as near-zero energy buildings (nZEB) in Spain’s Building Technical Code (“Código Técnico de la Edificación”, CTE) and aligned with EU Directive 2010/31/EU.
Energy renovated residential building.
This energy indicator identifies existing residential buildings that, after undergoing refurbishment, achieve a non-renewable primary energy consumption (NRPEC) low enough to be deemed efficient under the CTE.
Passive buildings.
This energy indicator identifies residential buildings whose calculated annual space-heating demand and space-cooling demand are each ≤ 15 kWh/m²·year.
Final energy consumption.
This energy indicator quantifies the total final energy (kWh/m²·year) consumed by a building and not produced by on-site renewable sources.
Heating energy consumption.
This energy indicator quantifies the total non-renewable primary energy consumption devoted exclusively to space-heating systems in a building, expressed in kilowatt-hours per square metre of conditioned floor area and year (kWh/m²·year).
CO2 emissions.
This energy indicator quantifies the operational carbon footprint of a building, expressed as kilograms of CO₂ emitted per square metre of conditioned floor area per year (kg CO₂/m²·year).
Photovoltaic generation potential.
This energy indicator estimates the annual electrical output a building could generate from a photovoltaic (PV) system installed on its roof, expressed in kilowatt-hours per square metre of roof area per year (kWh/m²·year).
Socio-economic
Housing prices.
This indicator captures the average rental price per square metre (€/m²) of dwellings within each residential building
Average household income.
This indicator represents the average annual net income of all individuals residing within a household, expressed in euros (€), and is calculated for the aggregate of households located in a given building.
Average rent compared to household income.
This economic indicator quantifies the percentage (%) of average household income that households within a given building would need to allocate towards rent payments.
Population with income below 60% of median.
This indicator measures the proportion of residents within each building whose economic status places them at risk of poverty, defined by having household incomes below the established poverty threshold
Environmental
Vulnerability to heatwaves and temperature rise.
This indicator assesses the level of vulnerability of buildings to extreme heat events, such as heat waves and rising summer temperatures, expressed on a scale from 0 to 9.
Green space area.
This indicator quantifies the total area of green spaces, expressed in hectares, within a 400-metre radius of a given building.
Urban facilities within a 15-minute walk.
This indicator measures the number of different facilities located within a walking distance equivalent to 15 minutes from a given building.
Access to cycle lanes.
This indicator measures the presence of cycling infrastructure within walking distance of residential buildings.
Access to recharging point.
This indicator evaluates the adequacy of electric vehicle (EV) recharging infrastructure in proximity to residential buildings.