The development of bioclimatic technologies for energy retrofitting of building envelopes is crucial for achieving energy efficiency and sustainability in the built environment. Beyond addressing these challenges, opaque ventilated façades (OVFs) can contribute to reduce cooling energy demand, being a solution toward decarbonized buildings. The system operates by absorbing solar radiation on the external coating, which heats up and warms the air, creating a stack effect in the cavity. This natural convection phenomenon expels heat from the cavity, lowering the temperature of internal walls and subsequently reducing the building’s cooling loads. The studies on OVFs have overlooked the presence of obstructions within the cavity, which are essential. Indeed, structural connections are necessary for the mechanical anchor of the coating to the massive wall, while horizontal metallic frame serves as a support for the external cladding façade, guaranteeing stability. These obstructions introduce additional pressure drops, reducing the mass flow rate within the cavity, weakening the stack effect, so diminishing the heat expelled. Consequently, this affects the heat flux entering the building wall. This study aims to evaluate the impact of these obstructions on the thermal performance of ventilated façades using three-dimensional computational fluid dynamics (CFD) analyses. The necessity of multi-dimensional analyses arises from the need for a representation of the stack effect, for an accurate assessment of the outgoing heat flow from the cavity. Specifically, a comparison between configurations with and without obstructions in terms of cooling load and energy expelled from the cavity is presented.