Mean and diurnal indoor air humidity loads in residential buildings

Abstract

In this study, indoor air humidity and temperature levels have been measured in 117 houses in Trondheim, Norway. The houses were randomly selected for each of the following types: detached one-family houses, semidetached two-family houses, row houses, and apartment buildings. The temperature and relative humidity (RH) were measured at 15-min interval over a period of 1 week. The measurements were made in bedrooms, living rooms, bathrooms, and outdoors. The internal moisture excess, which is the difference between indoor and outdoor air water vapour content, was calculated. The dataset was analysed in regard to average values of internal moisture excess and its dependency of outdoor climate. The daily variations of indoor RH, temperature, and internal moisture excess for the various types of rooms were also analysed. The typical diurnal variations of RH, temperature, and internal moisture excess are presented together with the statistical variation. The effect of influencing factors such as occupancy (area per person), type of basic ventilation of the house, type of building, time of the year, and the level of average indoor air humidity was investigated. To get a deeper understanding of some of the factors influencing the diurnal variations of the indoor air humidity observed in the field measurements, computer simulations of the indoor air humidity were also performed. The simulations were made using the numerical software WUFI Plus.