Climate change and extreme heat are critical issues which have been faced all over the world. Consequently, designers strive to monitor and assess the performance of facades by developing environmental assessments at the early design stages, since design changes do not require many resources. Rapid urban expansion in many parts of the world is leading to increased exposure to extreme natural hazards, exacerbated by climate change. It is essential to come up with strategies for mitigating the vulnerability of the built environment. The concept of thermal resilience and adaptation to climate change have gained ground and international attention in the Architecture, Engineering and Construction (AEC) industry. Resilience is a multi-facet property which defines the vulnerability of the built environment. Although the qualitative assessment of resilience value, the quantification of urban resilience is not yet representative enough and there is a lack of calculating the resilience in the built environment. However, designers are called to develop building and planning proposals with taking into consideration the thermal resilience of buildings against extreme hazards. This thesis aims to fill the gap between the qualitative and quantitative evaluation of thermal resilience in buildings by considering the operational building performance and the thermal performance of the building envelope in case of extreme heat waves. Towards this direction, the most influential parameters of thermal resilience are identified by implementing a sensitivity analysis process, in the first part. Secondly, a quantification method is presented and the thermal resilience performance for buildings in Amsterdam is calculated. Last, this thesis attempts to develop a computational workflow in order to assist designers and engineers in defining the thermal resilience index from the early design stage. Defining a less computational cost and time-consuming workflow is also a goal. Due to time limitations, the multi-facet aspect of resilience and the difficulty of quantification of its indicators, this research focuses on the ex-ante evaluation of the building envelope by identifying its vulnerability to extreme heat waves.