Summertime impacts of climate change on dwellings in Wales, UK

Wales's climate is predicted to be warmer and wetter, and ‘hot’ summers are expected to become more commonplace by the middle of this century. Whilst the focus of climate change adaptation in Wales has been wintertime decarbonisation through the introduction of energy efficiency measures, Welsh Government now want to understand the summertime impacts of climate change on the occupants of Welsh housing. The aim of this project was to test the hypothesis that summertime indoor housing conditions in Wales will diminish as a consequence of climate change. A six-week period from 22nd July–31st August was modelled using UK 2018 local climate projections, baseline, 2030 and 2070 respectively. The results reveal increased incidences of summertime overheating in a majority of dwellings. The poorest performing dwellings were post 1990 dwellings, flats and properties with internal wall insulation. The results show that cooling strategies to reduce indoor air temperature will increasingly be required. The other indoor vulnerability modelled was that of moisture. Results demonstrate the potential for poorer indoor environmental quality due to increased relative humidity. Every location will experience increases in relative humidity regardless of dwelling typology. Relative humidity will be highest in pre-1919 dwellings and dwellings with solid stone walls. The results show that ventilation strategies to improve the extraction of moisture-laden air, whilst diluting the concentration of pollutants that are present indoors, are required if these dwellings are to avoid increased incidences of condensation, damp, and mould growth, and adverse impacts from other allergens, particles and pollutants.