The aim of this study is to address significant psychoacoustic parameters able to qualify and classify cooling fan systems noise. Today, manufacturer acoustic specifications are essentially based on acoustic level (dBA) which is insufficient to indicate annoyance. In order to propose new psychoacoustic criteria, subjective assessment of the sound comfort of different cooling fan systems by a listening jury is first made. Computation of psychoacoustic criteria and comparison between amplitude spectra of the different recordings is then realized. Other experiments performed on time varying rotating speed provide information on annoyance threshold. The correlation established between subjective annoyance and psychoacoustic metrics leads to develop a global index corresponding to the signature of cooling fan systems. This index gives quantitative values on subjective annoyance and open future prospects.