The necessity of restraining global warming to 1.5 C (IPCC Special Report 2018) implies many actions at global and local level in order to reduce CO2 emissions to net zero by 2050. Moreover, in urban area, the intensity of more and more frequent heatwaves is magnified by Urban Heat Island (UHI) effects and it increases the production of CO2 due to the intensification in cooling demand. Over the years, the historic settlement (medieval town) has showed to be more resilient to temperature changes than modern district. This paper compares the historic district with the modern one in Bari (southern Italy) in terms of morphology, type and construction technology through Envi-met simulations. It highlights how the fabric of the old town may have positive impact on summer regime for thermal comfort and its analysis can be useful for the definition of some guidelines for contemporary settlement. Natural solutions (eg vegetation, green roofs and water jects) and cool materials are proposed to reduce energy demand according to EU directive 2018/844 and complying with the constraints for consolidated urban area. The aim is also to evaluate the solutions for microclimate mitigation of urban canyons towards zero energy settlement starting from the old town features.