The energy performance of any building depends on its orientation, the architectural and constructive design of its envelope and the energy systems installed within it. A highly glazed envelope is sometimes chosen for its aesthetics and transparency, offering maximum natural lighting and solar gain. The potential drawbacks of such an architectural choice, namely the cold-wall effect in winter associated with heat loss, and overheating in summer, call for fine-tuned energy optimization of the coupling of the envelope with the systems, particularly those managing ventilation and solar shading in hot weather. The aim of this study is to numerically test renovation solutions for a commercial building with two heavily glazed facades, facing south-east and north-west. An initial validation stage of the model reproducing the building's current state is based on actual monthly heating consumption. It is then shown that the addition of a double-skin wall protects the building against overheating in summer, and coupled with ventilation in winter, preheats the fresh air, thus minimizing aeraulic losses. The addition of a buffer zone on the north-west side reduces the maximum summer temperature by 4 ℃, at the expense of a 9% increase in heating consumption due to reduced mid-season solar gain.