Influence of weather and indoor climate on clothing of occupants in naturally ventilated school buildings

Adaptive thermal comfort standards hold the potential for energy savings and greenhouse gas emission reductions in naturally ventilated buildings. The potential for energy savings relies on the fact that applying adaptive standards, indoor comfort temperature is shifted up on warmer days and shifted down in colder ones. In order to determine the correct comfort temperature inside, two variables need to be known in advance: The clothing insulation level and the metabolic activity of the inhabitants. Using an adult population, it was observed that the clothing insulation level can be calculated based on recent thermal memory and weather prediction. The field study was carried out with 732 individuals for one year. All individuals performed the same task. In these circumstances, the clothing insulation level revealed to be a key issue. The clothing insulation level of the population was determined by the clo-checklist method and showed significant variation along the time period, with standard deviation representing about 23% of the mean clo (1 clo = 0.155 m2 K W−1). Results showed that the clothing insulation level worn inside has the most significant relationship to the previous day’s average outside temperature (Tday.x−1: R2 = 88%) followed by the maximum outside temperature during that day (maxTday.x: R2 = 71%).