Building energy simulations are important to assess the performance of buildings and to design solution aimed at reducing energy consumption and carbon emissions. Many software perform these simulations, focusing on systems operations and energy losses and gains. When it comes to modelling historical buildings, the simulations could be also used to estimate the risk of damages and decay processes. This paper presents the first results based on twelve standardised exercises at increasing complexity for the comparison of microclimate simulations modelled through three whole-building hygrothermal dynamic simulation (BDS) software, specifically IDA ICE, WUFI PLUS and ENERGY PLUS. Differently from the already available testing procedures, this research focused on the physical variables that are relevant for conservation of historical buildings (i.e., temperature (T) and relative humidity (RH)). Starting from Common Exercise 0 (CE0), seven simulations were customised to capture differences in T values. Then, five building models were specifically conceived to consider some typical features of Historical Buildings (HB0): small windows size, heavyweight structures, low insulation of roofs, large volume and free-floating conditions. In the case of CE0, a good agreement was found in the simulation of indoor T. In addition, detailed windows reduced the discrepancy in T results with respect to the use of simplified windows. In the case of HB0, small windows slightly affected the microclimate simulations regardless of the number of transparent elements and their position. RH variability was driven only by T as the partial water vapour pressure was affected only by infiltrations through the building. To conclude, the comparison allowed to highlight some criticalities due to different model implementations such as weather file timestamp interpretation, window models or irradiation calculations. HB0 models could be used for software and models comparisons, new software testing and training activities.
