Mapping the effects of energy poverty on thermal comfort and skin temperature profiles of residents : a field study of naturally ventilated multi-storey social housing in Colombo Metropolitan Region

Abstract

Global warming is causing unprecedented climatic extremes and a rapid rise in urban temperatures, leading to overheated indoor environments. This issue is particularly critical for residents of social housing with deprived socio-economic backgrounds, as they face an increased risk of heat-related health implications. These conditions underscore the urgent need to enhance indoor thermal comfort and living standards in urban social housing. In response, this study conducts an experimental investigation into the indoor thermal conditions of a naturally ventilated 12-storey social housing building in Colombo, Sri Lanka. The research methodology combines field surveys, in-situ measurements of thermal environmental parameters, and infrared thermography, using a representative sample of 98 residents and their household units. Findings reveal that indoor temperatures ranged from 30.4°C to 34.2°C, indicating significant indoor overheating. The mean relative humidity was elevated at 63%, while a low mean air velocity of 0.1 m/s indicated poor natural ventilation. A mean thermal sensation vote (TSV) of 2.2, along with 90.8% of residents expressing a preference for significantly cooler conditions, highlights widespread thermal discomfort. Additionally, 38.8% of households were identified as multi-dimensionally energy- poor, with a significant correlation observed between higher levels of energy poverty and increased thermal discomfort. Skin temperature analysis revealed elevated mean facial temperatures, with the forehead showing the highest at 35.5°C. This analysis further suggests a strong association between elevated facial skin temperatures and greater thermal discomfort. According to the linear regression method, the comfort temperature was 28.8°C, while the Griffiths method estimated it at 27.3°C. To cope with thermal discomfort, residents frequently used adaptive behaviours such as using fans (89.8%) and going outside (53.1%), while bathing (18.4%) and changing clothing (6.1%) were less preferred. These findings highlight the urgent need for tailored interventions to improve living standards in social housing and offer valuable insights to inform policies and strategic initiatives aimed at enhancing residents’ quality of life.