In this paper an assessment of the use of mixed mode ventilation is performed using dynamic simulation software with a typical office building as a testcase. The study is performed under future weather data to make sure the design will last through the building lifecycle. Future weather data of Lebanon isgenerated using Climate Models to perform the future simulations. The model assessed is simulated using current construction practices, 19% energysavings are expected in the future. To increase the future energy saving potential of the system, thickening of walls and including 5 cm (0.16ft) insulationwas studied which decreased the energy consumption further and made the mixed mode process save 24% in the future. Then double glazing was usedinstead of single glazing for the building which lowered the energy consumption and the future savings became 23% against the base case. These twomeasures proved efficient in the present and the future. The best way to enhance the use of mixed mode ventilation in the present and the future is then touse a combination of those two measures.