The aim of this paper is to present a control scheme for controlling the temperature in a slab which is not directly measurable. The process can only be controlled by manipulating the ambient temperature (boundary control). We describe the physical process and derive its (distributed) transfer function (DTF). The sensitivity of the model for one of the parameters is analyzed. We describe a model reduction technique which provides an accurate approximation of the distributed transfer function. Based on the reduced order model we present an Internal Model Control (IMC) scheme applied to the heat process and analyze the closed-loop.reduced order model