Climate change is increasingly recognized as a reality that requires action, not only by society in general but also by policy decision-makers and scholars. In addition to the increase in mean temperatures, climate models indicate an increase in frequency and severity of extreme events, such as heatwaves. Therefore, indoor environmental conditions in existing residential buildings can be significantly affected, since these were not initially designed to endure such conditions. These changes may compromise their ability to moderate outdoor temperatures, particularly in regions such as Southern Europe, where most buildings still rely on natural ventilation.
This work aims to approach this topic by integrating two different interpretations of
vulnerability – outcome and contextual vulnerability –, with the purpose of providing
information to support policy design and decision-making, and also the development of retrofit interventions. Using a case study from Lisbon (Portugal), four studies were developed independently based on different methodologies, including thermal modelling and questionnaires.
Results from thermal simulations suggest that construction type seems to be determinant in defining the building”s ability to moderate high outdoor temperature. Findings also indicate that it is possible to offset or reduce the effect of the increase in temperatures by means of cost-effective passive measures applied to the building envelope. Some non-physical characteristics such as occupancy and window control are also significant, allowing up to a 91% reduction in discomfort hours. Although useful, this view does not reflect all facets of vulnerability to high temperatures, as simulated behavior cannot illustrate the diversity of practices adopted by occupants nor the context where they occur, For this reason, statistical techniques such as factor and variance analysis were applied to data obtained from a survey to buildings” occupants and allowed to characterize occupant behavior in two main types of
practices – personal and environmental. Results suggest a statistically significant variance of socio-demographic, personal and contextual factors in relation to the individual adoption of adaptive practices. In particular, building characteristics, age and sex of occupants seem to be relevant in terms of behaviour towards the provision of comfortable conditions.
Integration of results regarding the two interpretations, namely regarding the relation between occupant and the building, support the socio-technical perspective of comfort and highlight the need for a systemic view over high-temperature vulnerability in planning retrofit interventions and designing adaptation policy instruments, including the use of policy mix and integration with other sectors
