This article deals with summer comfort and room air distribution in low-energy housings. In such buildings, the efficient thermal insulation and air tightness make it crucial to efficiently dispose of the heat released by the internal gains. In this prospect, the comfort in a test room resulting from an integrated cooling and ventilation system is assessed both experimentally and numerically. The air is supplied into the room close to the ceiling through a wall-mounted diffuser of complex geometry composed of 12 lobed nozzles. Experimentally, the air velocity, CO2 concentration, indoor air, wall and globe temperatures are monitored to assess the indoor environment quality. Numerically, CFD software Star-CCM+ is used to provide valuable information on the airflow patterns in the room. The CFD simulations are run in two steps in order to correctly integrate the complex diffuser’s geometry. An excellent indoor environment is obtained in the studied conditions. Furthermore, a parametric study is performed in order to investigate the influence of the heat sources and of the supplying conditions on the airflow and on the resulting comfort.