Small ducted fans in HVAC applications are often affected by their integration within the final product. The flow and operating conditions induced by the fan working environment significantly impact its noise emission and aerodynamic performances. This paper presents a combined numerical/experimental approach using LES simulations and multi-ports measurements to investigate such installation effects for a centrifugal fan subjected to distorted inflow conditions. We observe that the distortion increases the fan broadband noise while suppressing its tonal emissions and we attribute those changes to the lack of constructive interference between individuals blades' forces in distorted inflows.