The building envelope is normally subject to thermal and moisture gradients in practice. Due to the interrelationship, thermal and moisture transfer should be simultaneously calculated for an accurate building performance evaluation. The aim of this study is to investigate the effect of moisture transportation on energy efficiency, thermal comfort and mould growth risks in residential buildings based on the hygrothermal simulation. First, hygrothermal simulation is conducted to evaluate the energy efficiency and IAQ in the selected residential building. This paper also provides characteristics of the hygrothermal properties of domestic building materials which are used for the selected residential building. Differences between experimental data for the domestic materials and properties from embedded data in the hygrothermal simulation program are discussed. Second, a hygrothermal calculation model is calibrated with the measurement data for indoor air temperature and relative humidity in the selected residential building. Lastly, we illustrate the effect of moisture transfer on the overall building performance by comparing the hygrothermal simulation results with thermal-only simulation (only consideration of heat transfer through the building envelope) results. The results suggest that heating and cooling energy can be underestimated without consideration of moisture transportation mechanisms in the building energy simulation. Moreover, results show that the moisture buffering effect could significantly reduce the amplitude of relative humidity fluctuations during all seasons. (C) 2014 Elsevier B.V. All rights reserved.