With climate change projected warming temperatures, ensuring that buildings designed and built today will be adapted to future extreme heat is essential. For this purpose, the use of an optimisation algorithm is appropriate to identify best designs in both present and future climate. Future weather files with heatwaves allow to assess the overheating risk in different building designs. For the proposed building case-study, results are presented with two different ventilative cooling solutions, with a reference configuration with only hygienic ventilation, with mechanical free-cooling and with natural ventilation. Results indicate strong design tendencies regarding the building fabric (thermal mass, glazing percentage and cool paints), different for the two casestudy cities.