The process of radiative heat transfer is electrically simulated by using voltage-dependent resistors in conjunction with current transference circuits, and so an analogue is devised which shows how the overall uni-directional heat transfer by simultaneous conduction and radiation across a transparent gas space is a function of the positions of radiation shields which may be interposed between the bounding surfaces. The results for single and double shield systems are in close agreement with digital computer calculations and suggest a relatively simple procedure for establishing a favourable set of positions of any number of shields.