An analytical model is derived and tested for heat transfer in injection moulding systems with coating layers or active heating elements attached to the mould walls. For this purpose a simple one-dimensional layer model was considered and convection and viscous dissipation contributions were neglected. A simple expression for the effect of the coating thickness and conductivity on the cooling time is derived. Further, the heating element model was tested with a specially designed heater cell. The measurements compare reasonably well with the predicted temperature response.