In Belgium, the installation of a small wind turbine on rooftops is still very uncommon. Currently, there is no dedicated legal framework governing the installation on a building. Nevertheless, over the past years, our research group has received several demands from building owners wanting to install one or several turbines on their rooftop. The lack of a dedicated framework requires increased attention throughout the whole procedure. To prevent potentially harmful installations, we developed an approach to assess the feasibility of such initiatives. This paper reports a complete feasibility study to install a 3 kW wind turbine on the South Tower (the highest building in Belgium). The paper reviews the main steps from the concept towards the installation of a turbine on a high-rise rooftop. In overall terms, the installation of a 3 kW turbine on top of the South Tower has little impact on the building and its nearby environment. From an environmental perspective, the installation of a small building-mounted wind turbine on a rooftop can be meaningful. However, even in good wind conditions, the economic viability of the 3 kW turbine is low. This is mainly caused by the high study cost. Therefore, their global cost might still hold back potential investors.