The goal of this thesis is to study the service life of a curtain wall and identify which is the best duration in terms of sustainability. Two scenarios, one short-term and one long-term, will be analysed and eventually compared in order to make the final decision. For both scenarios the embodied energy and CO2 emissions will be calculated. Time and expenses will be taken into consideration. The designs of the details and the material selection will be reconsidered and, when needed, changes will be implemented. The evaluation will be implemented for a stick curtain wall and a unitised as well.