AbstractGlobally, populations are ageing and the UK is no exception. By 2050 it is anticipated that almost a quarter of the population will be aged 65 and over, compared to 18% currently. Evidence suggests that many older people wish to remain in their home as they age, but in doing so may compromise their health and longevity. Older people are known to spend over 90% of their time indoors, often in poor quality housing. As the demographic with the highest prevalence of chronic health conditions, housing that exacerbates this is concerning. Despite a relatively mild climate the UK excess winter death (EWD) rate is the highest in Europe, and with 92% of the 28,870 yearly deaths occurring in the 65+ demographic, older people are most vulnerable. By contrast, less extreme summers lead to lower instances of summertime mortality, however, climate change is likely to alter this. Extreme temperatures found in homes of older people seem to increase their susceptibility to morbidity and mortality, but despite this very little is known about older people’s thermal comfort and indoor environment. This thesis presents research conducted as part of the UK’s first longitudinal temperature monitoring study focusing on the 65+ demographic. Data was recorded throughout two heating and two cooling seasons by temperature and humidity sensors. Alongside this, monthly surveys capturing demographic, housing, thermal comfort and health characteristics were disseminated. During the final heating season, interviews were conducted in a subset of the known coldest homes (based on the prior heating seasons results), to identify coping strategies used by older people in maintaining their health and well-being during exposure to low temperatures.
For the heating seasons, older people were found to be comfortable at lower temperatures than guidance recommends, in contrast to outputs of the PMV/PPD model, which significantly underpredicted true comfort. Furthermore, the low temperatures did not seem to adversely affect instances of morbidity and mortality in the sample, however, this could have been influenced by sample size and selection bias. Feelings of comfort were echoed in the interviews, where despite participants recognising their internal temperature could be higher, they felt satisfied.
During the cooling seasons, both the PMV/PPD model and the adaptive model were unable to accurately predict occupant thermal comfort. The study captured a typical and an extreme summer and although, as expected, a larger proportion of the sample were found to be overheating in the extreme summer compared to the typical summer (94% compared to 57%), the majority of self-reported comfort votes fell within acceptable parameters for both summers. Furthermore, instances of morbidity and mortality were not found to be higher in the extreme summer compared to the typical summer.
This thesis demonstrates a disconnect between thermal comfort models and self- reported comfort of older people in both heating and cooling seasons. This has clear implications for under and overheating analysis, since both models’ failure in capturing comfort highlights the challenge of safeguarding the ageing population’s health within their homes, whilst ensuring over-prediction of comfort does not cause emissions to be increased needlessly through higher than necessary recommended internal temperatures.
|Date of Award||19 Jun 2019|
|Supervisor||Ian Walker (Supervisor), Afroditi Stathi (Supervisor) & Sukumar Natarajan (Supervisor)|