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

Abstract

Historic buildings have been gradually considered within energy efficiency practices and renewable energy systems, but the implementation of such measures is more complex for historic buildings. It is fundamental to understand the importance of users in the heritage-energy sector. Thus, energy conservation practices of historic buildings that involve less invasive interventions that could lead to loss of value must be promoted. The paper illustrates how residents of historic buildings in the Historic Centre of Mexico City (World Heritage) make decisions on energy efficiency with the ultimate goal of improving thermal comfort and reducing energy consumption. This study consists of five in-depth semi-structured interviews complemented by monitoring internal environmental conditions such as temperature and relative humidity. The thematic analysis of the interviews was followed by a system dynamics analysis to better understand the changes in decision making over time. The dynamic hypothesis is that heritage values assigned to historic buildings change over time and they drive or prohibit changes in energy efficiency. Moreover, a tension arises over time between the limitations on listed buildings in which making many changes in use and energy efficiency interventions is prevented. Our results show that participants take passive thermal-comfort actions (e.g., wearing more clothes and closing windows) when internal temperatures are low. They oppose major interventions or invasive retrofitting to the building, given the high cost and potential loss of value assigned to their buildings. The changes the users would consider while dealing with uncomfortable internal conditions are small interventions in floors and ceilings; however, they avoid making changes to aspects they consider are important and must be preserved and protected (social and cultural values). Integrating the understanding of users’ behaviours toward energy efficiency and heritage values can enhance retrofitting policies and guidelines that help protect and maintain the heritage-built stock.