Environmental impacts of standard building renovations: City-level extrapolation from a real case study in Spain

Monzón-Chavarrías, Marta (Universidad de Zaragoza) ; Sierra-Pérez, Jorge (Universidad de Zaragoza) ; García-Pérez, Sergio (Universidad de Zaragoza) ; Guillén-Lambea, Silvia (Universidad de Zaragoza)

Resumen: The renovation of multi-family buildings aimed at reducing operational energy consumption and improving housing health and safety is a common practice across Europe. However, in response to climate change, the European Union has established ambitious targets for 2050, which require not only reductions in operational energy use but also a significant decrease in embodied energy and CO2 emissions associated with building renovations.
This study presents a comprehensive analysis of a social housing building in Zaragoza, Spain, which underwent renovation aimed at reducing energy consumption, enhancing indoor environmental quality to improve residents’ living conditions. A detailed inventory of materials and construction processes was compiled, and both the embodied energy and CO2 emissions associated with the renovation phase were calculated and compared before and after the intervention, including an estimation of payback times.
Additionally, the study extends the analysis to the urban scale by selecting buildings with similar characteristics and creating a digital twin using programming tools, in order to assess environmental impacts and payback periods across a broader context.
The results highlight that the renovation works aimed at reducing operational energy—such as façade and roof insulation, window replacement, and system upgrades—account for less than 50% (47.5%) of the total embodied energy of the renovation. In terms of Global Warming Potential, however, this share increases to 74.9%.
Regarding payback periods, the non-renewable Energy Payback Time is 1.35 years at the building scale and 1.12 years at the city scale. For CO2 emissions, the payback time is 1.62 years at the building scale and 1.35 years at the city scale. These results demonstrate that the renovation—implemented with conventional materials—achieved significant reductions in energy use and emissions. Even greater benefits could be achieved by incorporating materials aligned with circular economy principles. These interventions should also be leveraged to enhance the quality of life of residents by adopting new approaches to adaptability and the reorganization of interior spaces, thereby pursuing optimal functional renewal.

Idioma: Inglés

DOI: 10.1016/j.enbuild.2025.116938

Año: 2026

Publicado en: Energy and Buildings 354 (2026), 116938 [16 pp.]
ISSN: 0378-7788

Financiación: info:eu-repo/grantAgreement/ES/AEI/PID2023-151255OB-I00

Tipo y forma: Article (Published version)

Área (Departamento): Área Construc. Arquitectónicas (Dpto. Arquitectura)
Área (Departamento): Área Expresión Gráfica en Ing. (Dpto. Ingeniería Diseño Fabri.)
Área (Departamento): Área Urbanística y Ord.Territ. (Dpto. Arquitectura)
Área (Departamento): Área Máquinas y Motores Térmi. (Dpto. Ingeniería Mecánica)