This article investigates the influence of the thermal performance of building envelopes on annual energy consumption in a ground-buried office building by means of the dynamic building energy simulation, aiming at offering reasonable guidelines for the energy efficient design of envelopes for underground office buildings in China. In this study, the accuracy of dealing with the thermal process for underground buildings by using the Designer's Energy Simulation Tool (DeST) is validated by measured data. The analyzed results show that the annual energy consumptions for this type of buildings vary significantly, and it is based on the value of the overall heat transfer coefficient (U-value) of the envelopes. Thus, it is necessary to optimize the U-value for underground buildings located in various climatic zones in China. With respect to the roof, an improvement in its thermal performance is significantly beneficial to the underground office building in terms of annual energy demand. With respect to the external walls, the optimized U-values completely change with the distribution of the climate zones. The recommended optimal values for various climate zones of China are also specified as design references for public office building in underground in terms of the building energy efficiency.

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The urban heat island (UHI) and urban moisture island (UMI) effect can be significant in Hong Kong due to its high-density land utilization, and this can strongly affect building energy performance. While the UHI' energy impact has been rather intensively studied recently, the UMI effect on latent energy is still underexplored, especially for humid subtropical climate like Hong Kong. This study investigated the intensity of UHI and UMI in Hong Kong, and its impacts on the sensible and latent cooling demand of residential buildings in summer. Firstly, a ten-year weather dataset from 2004 to 2013 for the six stations selected based on the local climate zone (LCZ) scheme was analysed. The results show that the urban area of Hong Kong appears as both a heat and moisture island during summer nights but as cooling and dry islands during daytime, and the nocturnal UHI and UMI intensity vary significantly with different LCZs. Furthermore, the energy performance of a typical residential building in Hong Kong was simulated with measured weather data for the selected stations as an input. The urban building shows a higher sensible cooling demand, approximately twice that of the comparative rural one, and the latent cooling demand could be up to 96% higher. Both sensible and latent cooling energy demand decrease with increasing LCZ grades. Our study highlights that both UHI and UMI effect should be considered in the estimation of building energy in Hong Kong due to their significant impacts on the cooling energy demand.