Addressing the relationships between ageing, thermal comfort, house design and health: A study in South Australia

Abstract

There is a large body of evidence linking extremes of outdoor temperature with morbidity and mortality amongst older people; less is known about the indoor conditions of the houses older people live in. This is despite the fact that it is well documented that older people spend most of their time inside their houses. As the overwhelming preference amongst Australian people aged 65 and over is to remain in their home as long as possible. it is thus important to understand the relationship between the indoor thermal conditions, the perception that occupants have of these conditions, and the reactions they have to these conditions, to allow them to stay healthy and comfortable as they age in place. The research presented in this thesis has been conducted to address the relationships between ageing, thermal comfort and health, and the housing conditions of a group of older South Australians. As part of this study, a survey was undertaken to investigate the satisfaction amongst older people in regard to their housing, comfort and health. The survey found that most were satisfied with the level of year-round thermal comfort provided by their homes, and typically used their heating and cooling devices sparingly to achieve thermal comfort. Participants were more concerned about their health during heatwaves than they were during cold weather. Following the survey, a field study of 18 houses was carried out to further understand the indoor thermal conditions and occupants’ thermal comfort as well as the relationship between these variables and self-reported symptoms. The results showed a consistent trend toward a preference for cooler conditions than predicted by current thermal comfort standards. All but one of the participants reported thermal satisfaction at lower temperatures than predicted, but expressed no preference toward warmer conditions. These preferences, however, may be problematic, as the study also showed that a relationship exists between indoor minimum and maximum temperatures and the presentation of heat- and cold-related symptoms. This relationship is binomial: symptoms are related to temperatures at both ends of the temperature spectrum. The frequency of the presentation of symptoms increased and temperatures for lower or higher, for both daily maximum and minimum temperatures. Temperatures in the houses were lower than recommended by these field study results for 50% of the time, even when heating and cooling systems were used. Whilst there were some issues of overheating, the main concern that the study uncovered was the under-heating of houses. A sample of houses from the field study were then included in a study of building improvement, using a building performance simulation technique, to investigate how retrofitting insulation and double glazing might improve conditions in the houses. Simulated results showed that basic building improvements would slightly increase the time during which the temperature of the house was in the optimal range; however, there was still a need for more heating than is currently utilised by this cohort. Increasing heating use, however, increases the cost to the occupants, which some older people may not find affordable. This in turn could dissuade occupants from the recommended heating increases. For this reason, this study then examined the benefit of installing solar photovoltaic cells as a solution which offsets increased cost needed to adequately heat the building whilst being cost-neutral in a relatively short time span. A home environment that is conducive to thermal comfort and good health has the potential to allow older people to age in place, to prevent hospitalisations and to delay entry into residential aged care. It is thus in the best interest of home owners, policy makers and governments to consider building improvements as an investment in health. These stakeholders must work together to make a healthy thermal environment achievable and affordable, both for older people now and for the increasing numbers of older people in the future.