Adaptation strategies to prevent overheating in dwellings occupied by older people

The occurrence of heatwaves and hot weather has increased in the past few decades because of anthropogenic climate change. A prolonged heatwave in Europe in the summer of 2003 and the recent 2015 heatwave in India raised concerns about our understanding of their impact on indoor overheating and the wellbeing of occupants. The severity and duration of hot weather and heatwaves are projected to increase in a warming climate, with increased probabilities of serious overheating in buildings. Older people are at high risk during extreme heat events because of their physical and mental decline and diminished social interactions. The need to taking additional measures for the older people during warm weather has been highlighted by leading organisations such as the World Health Organisation (WHO) and the UK Department of Health. The ageing population is likely to exacerbate the situation. To promote healthy and independent living by older people, the design of the built environment needs to mitigate the difficulties due to increasing temperature while minimising the impact of overheating. As a precaution sufficient adaptation measures are necessary. Despite these concerns, little information is available about the indoor thermal state of existing dwellings occupied by older people and its capability to perform in projected hotter climates. Previous studies mostly focused on typical residential and commercial buildings and overlooked the occupancy profile, and social and behavioural patterns, as well as the architectural characteristics of dwellings occupied by older people. 

This study investigated: (a) the thermal performance of existing dwellings accommodating older people; and (b) outlined potential adaptation strategies to minimise the risks of overheating in these buildings. An understanding around the concept of thermal performance requirements and assessment methods were developed through literature review. Quantitative environmental data were collected over a 16-month period from four residential buildings accommodating older people: two communal establishments; one flat in a multi-occupancy building; and one retrofitted energy efficient house. Physical data collection was accompanied by interviews with the occupants to identify their perception of and ability to control the indoor environment. In addition, climate based dynamic thermal simulation was conducted to assess the overheating risks in projected climate scenarios and identify effective adaptation strategies to minimise the risk. 

The results identified that overheating performance for existing buildings may vary significantly based on building type. Most of the bedsits and flats in communal buildings with enclosed corridors were at high risk of overheating. The risk persisted for the retrofitted energy efficient house as well. A further analysis by dynamic thermal simulation determined the need for specific adaptation strategies for various building types; e.g. typical residential, communal buildings, etc. The research explored how various options, including architectural adaptation strategies and local climate control, can be applied to minimise the overheating risk. The study also identified that physical and psychological difficulties experienced by occupants may cause difficulties in controlling indoor climate during hot weather.

The study: highlighted the gaps and limitations in existing guides and standards; and discussed the challenges of overheating adaptation. Finally, an integrated approach of adaptation is proposed, which addressed strategic, planning and building level adaptation measures. Findings from this research have been designed to enable designers refurbishing and designing dwellings for the older people, local authorities and care givers to appreciate the importance of the topic and the need for appropriate strategies.