Winter performance, occupants’ comfort and cold stress in prefabricated timber buildings

This paper presents the results of the physical measurements, thermal comfort survey and building simulation considered in different units of a development in the Southeast of England. The study investigates the winter performance and cold stress in buildings built with prefabricated structural insulated panels (SIPs). The study employed the measurements of the parameters, administration of the questionnaire supplemented with interviews, discussions, and observations, as well as building simulations to collect data for analysis. The results showed 87% of the responses on thermal sensation ranged from slightly cool to slightly warm while 84% preferred no change to the thermal environment. On thermal acceptability, 93% of the participants highlighted that the thermal environment was right for them. For the measurement, the results showed a mean temperature of 18.6 °C. The neutral and preferred temperatures in the units are 21.5 °C and 24.5 °C respectively. The temperatures are found to be within the comfort range in winter. The findings revealed that prefabricated timber buildings perform better in winter than summer and occupants are thermally comfortable in winter. The study showed that a combination of variables like humidity, temperature, dew-point could influence the stress indexes. Regarding the assessment of cold stress indexes, the study recommends the WBGT of 14.3 °C and UTCI of 17.9 °C as the stress thresholds for the period of physical measurements in the winter. For the meteorological winter months (December–February), the research proposes the WBGT of 13.4 °C and UTCI of 16.6 °C for London Islington TRY while it recommends the WBGT of 13.3 °C and UTCI of 16.5 °C for St Albans TRY. The study revealed the possibility of slight cold stress for occupants of the buildings and further adaptive measures are required to reduce exposure of occupants to cold stress in the future.