Climate change has a dual implication on the built environment: on one hand human settlements and buildings are vulnerable to the effects of changing climate and on the other hand the building sector has a significant climate change mitigation potential. The relevant sustainable development and building policies as well as the building design, construction and maintenance strategies should jointly respond both to adaptation to and mitigation of climate change. What should city developers focus on in order to plan a sustainable and safe city in a changing climate? This paper provides answers to this question, presenting a bottom-up methodology based on a generalized building typology of the residential building stock in order to estimate the mitigation potential and vulnerability of the residential sector. During the research, a case study has been implemented in Hungary to assess the structural impacts and vulnerability on the roof, particularly with respect to the wind load and to estimate the potential decrease of CO2 emission through refurbishment. Through the case study the paper highlights the most problematic areas of the city both from vulnerability and mitigation point of view where the attention of the city developers should be turned.