A 2023 stakeholder study of the Historic Centre of Mexico City, a UNESCO World Heritage Site, distilled seven themes governing energy-efficiency and conservation decisions, but was a single-case qualitative study whose framework remains untested elsewhere, and the field lacks demonstrable monitored practice. The problem asks for energy-efficiency retrofit case studies in heritage buildings that jointly monitor heritage value (including user-assigned values), user thermal comfort and energy consumption before and after implementation, and for a predictive or systemic model of the dynamic interplay between user-assigned heritage values, everyday energy behaviours and the long-term physical condition of heritage buildings, calibrated on longitudinal data from actual retrofit projects. A 2026 systematic review confirms that post-intervention monitoring remains rare and analyses remain unbalanced between energy and conservation, so the open core survives: no published work tracks all three dimensions through implemented retrofits, and no validated predictive model of the values–behaviour–condition interplay exists.

Background

Buildings account for a large share of global energy use, and decarbonisation programmes now push deep energy renovation of the existing stock. A 'World Heritage Site' (WHS) is a place inscribed on the UNESCO World Heritage List for its outstanding cultural value; its buildings are typically protected by conservation doctrine that restricts alteration. An 'energy-efficiency retrofit' is a package of interventions — insulation, window replacement, airtightness work, heating and cooling system upgrades, renewable supply — intended to reduce energy consumption while improving indoor conditions. 'Thermal comfort' is occupant-perceived satisfaction with the indoor thermal environment, usually assessed through field measurements of air temperature and humidity together with occupant surveys. 'Heritage value' is the cultural significance ascribed to a building, ranging from expert-designated architectural and historic values to the values that users and residents themselves assign, which are dynamic and context-dependent. Retrofitting heritage buildings is difficult precisely because these dimensions collide: measures that save energy may erode historic fabric or user-assigned values, while conservation restrictions may block technically optimal solutions.

The immediate source of this problem is a qualitative study by Murillo Camacho, Fouseki and Altamirano (2023) of the Historic Centre of Mexico City, a WHS since 1987 whose building stock suffers severe deterioration while undergoing a publicly driven retrofit and social-housing regeneration programme. Using grounded theory and thematic analysis (qualitative coding methods in which conceptual categories are induced from interview data rather than imposed in advance), the authors analysed ten approximately two-hour semi-structured interviews with high-profile stakeholders from Mexico's heritage and energy sectors, complemented by an earlier resident study, and distilled seven interrelated themes shaping decisions: the condition of heritage buildings; deterioration, abandonment and investment opportunities; heritage values; user-assigned heritage and site values; building conditions for thermal comfort; investments in the heritage site; and heritage management and user-assigned values. The same research group had previously shown, through pilot studies combining resident interviews, indoor temperature and humidity monitoring, and qualitative system-dynamics analysis (a modelling style that represents a system as causal feedback loops rather than a predictive numerical simulator), that residents of heritage buildings on the same site prefer passive comfort actions, such as wearing more clothing, over invasive retrofit solutions for fear of losing heritage value.

The study's design leaves evident gaps: a small qualitative sample, a single case, an untested transferability of the seven-theme framework, and a field in which — as later reviews confirm — stakeholder opinion is not matched by monitored evidence from implemented retrofits. The unresolved target is to move from stakeholder opinion to demonstrable practice: to carry out retrofit case studies that actually implement energy-efficiency measures in heritage buildings while jointly monitoring heritage value, user thermal comfort and energy consumption, and to develop a predictive or systemic model of the dynamic interplay between user-assigned values, everyday energy behaviours and the long-term physical condition of heritage buildings.

Problem Statement

The problem is to close the gap between stakeholder opinion — as distilled for the Historic Centre of Mexico City by Murillo Camacho, Fouseki and Altamirano (2023), whose Conclusions call for a comprehensive conservation strategy that integrates users' values into policies for heritage areas and for methods and strategies to battle climate change while conserving historical and cultural values — and demonstrable practice in the energy retrofitting of heritage buildings in World Heritage contexts, through two complementary strands.

(1) Monitored retrofit case studies: design energy-efficiency retrofit case studies for occupied heritage buildings, specifying the interventions and a monitoring protocol that records, before and after the intervention and over a period long enough to observe seasonal and behavioural dynamics (at minimum one full annual cycle before and one full annual cycle after the intervention), all three of (a) heritage value, including user-assigned values, (b) user thermal comfort, and (c) energy consumption, together with the two modelling inputs (d) everyday energy behaviours and (e) the physical condition of the buildings.

(2) Predictive or systemic modelling: specify a model of the dynamic interplay between user-assigned values, everyday energy behaviours and the long-term physical condition of heritage buildings, together with an explicit calibration-and-validation protocol connecting it to longitudinal data from actual retrofitting projects, stating the model's variables and relations, its data sources (the monitored variables of strand (1) that it consumes, together with the everyday energy behaviours and the evolving physical condition recorded in those projects), and acceptance criteria for calibration and validation.

References

  1. Krisangella Sofia Murillo Camacho, Kalliopi Fouseki, Hector Altamirano (2023). Sustainability and Energy Efficiency in the World Heritage Site of the Historic Centre of Mexico City. Heritage 6(9), 6343–6357. DOI: 10.3390/heritage6090332. https://doi.org/10.3390/heritage6090332
  2. K. S. Murillo, K. Fouseki, H. Altamirano (2021). A sociotechnical approach to users' heritage values and decision-making processes for energy efficiency and thermal comfort in heritage buildings: A pilot study in Mexico City. IOP Conference Series: Earth and Environmental Science 863, 012031. DOI: 10.1088/1755-1315/863/1/012031. https://doi.org/10.1088/1755-1315/863/1/012031
  3. Krisangella Sofia Murillo Camacho, Kalliopi Fouseki, Hector Altamirano Medina (2022). Decision-Making Processes of Residents in Preservation, Thermal Comfort, and Energy Efficiency in Heritage Buildings: A Pilot Study in Mexico City. Applied Sciences 12(3), 1486. DOI: 10.3390/app12031486. https://doi.org/10.3390/app12031486
  4. Kalliopi Fouseki, David Newton, Krisangella Sofia Murillo Camacho, Sohini Nandi, Theodora Koukou (2020). Energy Efficiency, Thermal Comfort, and Heritage Conservation in Residential Historic Buildings as Dynamic and Systemic Socio-Cultural Practices. Atmosphere 11(6), 604. DOI: 10.3390/atmos11060604. https://doi.org/10.3390/atmos11060604
  5. Merve Karabeyeser Bakan, Kalliopi Fouseki, Hector Altamirano (2024). Investigating the Role of Thermal Comfort Perception on Negotiating Heritage Conservation and Energy Efficiency Decisions through System Dynamics. Buildings 14(6), 1800. DOI: 10.3390/buildings14061800. https://doi.org/10.3390/buildings14061800
  6. Pierfrancesco Fiore, Ilaria Di Nucci, Michele Grimaldi (2026). Compatibility of Energy Efficiency with the Protection of Historic Buildings: A Systematic Literature Review. Buildings 16(4), 839. DOI: 10.3390/buildings16040839. https://doi.org/10.3390/buildings16040839
  7. Daniel Herrera-Avellanosa, Jørgen Rose, Kirsten Engelund Thomsen, Franziska Haas, Gustaf Leijonhufvud, Tor Brostrom, Alexandra Troi (2024). Evaluating the Implementation of Energy Retrofits in Historic Buildings: A Demonstration of the Energy Conservation Potential and Lessons Learned for Upscaling. Heritage 7(2), 997–1013. DOI: 10.3390/heritage7020048. https://doi.org/10.3390/heritage7020048
  8. Zoe Kanetaki, Evgenia Tousi, Athina Mela, Eleni Kanetaki, Gianluca Pappaccogli, Emmanouel Proestakis (2025). Bridging Heritage Conservation and Energy Efficiency: Retrofitting Historic Social Housing in Mediterranean Cities. Atmosphere 16(12), 1321. DOI: 10.3390/atmos16121321. https://doi.org/10.3390/atmos16121321
  9. Keran Lan, Isarachai Buranaut, Yongduo Liang, Wei-Ling Hsu (2026). Development and Application of a Sustainable Post-Occupancy Evaluation Model for the Regeneration of Non-Designated Historic Buildings. Buildings 16(6), 1192. DOI: 10.3390/buildings16061192. https://doi.org/10.3390/buildings16061192
  10. Aya Miyazaki (2026). Applying Heritage Ecosystem approach to Mexico City's historic center: roles of authorities and communities in economic, political and cultural developments. Journal of Cultural Heritage Management and Sustainable Development, pp. 1–16 (published online 16 March 2026). DOI: 10.1108/jchmsd-08-2025-0287. https://doi.org/10.1108/jchmsd-08-2025-0287