The urban microclimate (UMC) can strongly affect the building energy demand. In this paper, the impact of the UMC on the space heating and cooling energy demand of buildings is analysed for typical office buildings in street canyon configurations, using detailed building energy simulations (BES). Convective aspects of the UMC are modelled using computational fluid dynamics (CFD) and data are transferred to BES, either by convective heat transfer coefficients or by directly coupling CFD and BES. Measured urban heat island intensities are additionally considered. Comparisons to stand-alone buildings show the large influence of the urban situation. We then outline multi-scale modelling concepts to consider UMC effects at larger urban scales, using a city energy simulation model and an adapted UMC model.