Dynamic simulation software based upon detailed building physics called THERB for HAM is used to predict hygrothermal environment of whole building. The accuracy of THERB is verified through the comparison of monitored and calculated values of temperature and humidity of the actual residential buildings. Then sensitive analysis utilizing THERB is performed with a number of factors, such as property, area and thickness of interior materials and so on, which influence indoor humidity, especially excessive dryness during heating. Eleven factors that affect indoor humidity are defined with the extent of the influence by the multiple regression analysis on the basis of the sensitive analysis. It is clarified that the THERB can accurately predict the hygrothermal environment of buildings and the extreme sensitive factors influencing indoor humidity are the moisture generation in rooms, outdoor temperture and humidity, moisture capacity of sorption and desorption materials, water vapour permeance of interior finish and the preset heating temperature.
