Nationwide longitudinal study on summertime overheating risk in English care homes

It is recognized that older people are a key vulnerable group disproportionately affected by extreme heat. Despite this, the residential care sector in England (UK) has historically addressed thermal comfort with an emphasis on keeping older residents comfortably warm through the winter, with much less consideration on keeping them comfortably cool in the summer.

This paper conducts a longitudinal empirical evaluation of the risk of summertime overheating in English Care homes in the non-heating seasons of 2022 and 2023, which were amongst the warmest on record in England. The nationwide study undertook environmental monitoring in 36 care homes throughout England during the non-heating seasons (May-September) of 2022 and 2023. Temperature and relative humidity were monitored in 125 indoor rooms – offices, lounges, bedrooms – alongside outdoor temperature and relative humidity at each care home site. Overheating metrics CIBSE Guide A and TM52 were applied to identify the extent and intensity of overheating experienced. Characteristics of the monitored locations were considered to identify those that were more or less likely to be overheating.

Across the full dataset, daily mean temperature during occupied hours reached peaks of around 29 deg^C in 2022 and 27 deg^C in 2023, with hourly means of 24.6 deg^C and 24.2 deg^C in 2022 and 2023 respectively. Locational characteristics were significant in determining the likelihood and intensity of overheating: care homes located in London experienced higher outdoor temperatures, leading to a higher propensity to high indoor temperatures and more intense overheating. However, care homes in the south of England experienced higher outdoor temperatures than those in the Midlands and North regions, but had lower prevalence and intensity of overheating than any other region. Many of these South care homes benefitted from being in rural localities (which had less overheating than urban and suburban care homes) and near the coast (which had less overheating than inland care homes). Whilst building characteristics (size and age) had little impact on overheating extent, ground floor rooms were found to be less susceptible to overheating compared to those on middle and top floors of the care homes.

Findings from this study will aid care home managers in addressing overheating risks and implementing necessary mitigation measures. They will also guide designers of new care homes in balancing overheating risks with year-round temperature comfort. Bespoke overheating metric may be required to accommodate both frail, often inactive elderly residents and more active staff in multi-functional residential environments.