A vortex tube (VT) is a very simple, yet effective device to generate instantaneous spot cooling effect, using compressed air as input. Present work is experimental analysis of effect of insulation on temperature separation performance of VT. Firstly, reliability of experimental setup and experimentation procedure is established through observation of transitional characteristics & energy balance. Then, interactive effect of inlet pressure (2-5 bar), cold mass fraction (0.1-0.9) and insulation on the performance of VT is investigated. In the second stage, essential parameters such as temperature and pressure values from experimentation were used to develop computational model of VT and results of experimentation were compared with CFD results. More importantly, utilization of flow physics derived from CFD model has been made to put forth the hypothesis about improvement in performance of VT due to insulation. For both insulated and non-insulated condition, temperature separation increases with increase in inlet pressure. Performance of insulated VT is better than non-insulated VT. It is proposed that significant heat leakage from atmosphere to VT is responsible for performance degradation of non insulated VT. Results of present experimental as well as CFD study in non-dimensional form are observed to be in good agreement with those of other works. Also, it is concluded that cooling power separation seems more realistic performance parameter of VT than cold end temperature alone. (C) 2017 Elsevier Ltd. All rights reserved.