Seasonal Indoor Humidity Levels of Apartment Suites in a Mild Coastal Climate

It is essential to design and operate buildings with good indoor air quality because people spend most of their time indoors, and their productivity, comfort, and health depend on the quality of the indoor air. In addition to other indoor-air-quality parameters, the indoor humidity and temperature need to be controlled and maintained within acceptable ranges. Elevated indoor humidity creates favorable conditions for mold growth and building-envelope damage. To minimize such problems, it is important that designers have insight into the level of indoor humidity that will be expected in a building operating under a set of conditions and weather variation. In this paper, the results of monitoring the indoor temperature and humidity of four apartment suites with different occupancy levels are reported. Along with the indoor-air conditions, the local outdoor temperature and relative humidity were continuously measured for 17 months. The indoor humidities in the suites were correlated with the outdoor air temperature and humidity and compared with the European indoor climate class model. Moreover, the indoor-temperature and relative-humidity ranges in the four suites during the winter, spring, summer, and fall seasons and the temperature and humidity distributions within the suites are reported.