Hi all, I'm a very new OpenStudio user. I'm trying to simulate an apartment building with ''natural-ventilation'' to evaluate which spaces are uncomfortable. I've modelled the building in ''sketchup-openstudio'' plug-in, and OS runs and gives the results. In OS thermal zones I've applied natural ventilation under zone equipment. I've run a simulation without and with the natural ventilation to different thermal zones and this is what I get: 1. No natural ventilation in blue, with natural ventilation in orange 2. I've noticed that changing ''minimum-indoor-temperature'' to 18 or 25 affects the zone air temperature in a way that I was not expecting. There is no other mechanical ventilation added therefore I don't understand where the additional heat is coming from during the winter time. What I was trying to achieve was to activate natural ventilation in summer to reduce overheat and reduce it in winter to retain heat. I've tried to apply a schedule to simulate that as discussed in this post but I was not successful. Thanks for your help and let me know if I should clarify something.