Control of material temperature distribution and governing phenomena during automated fiber placement is an important factor. Numerical modeling of the radiative heat transfer for a newly presented LED-based heating unit is developed and analyzed in theory. An optical model allows taking into account the radiative energy output of every individual LED. By adjusting the electrical input to the multiple LED arrays on the heating unit, the irradiance distribution on the substrate’s surface can be controlled. To investigate the capability to adjust the surface temperature distribution resulting from this feature, thermal models for two and three dimensions are developed and employed for the calculated irradiance distributions. The resulting temperature distributions show that temperature gradients can be avoided or created, depending on the input to the heating unit. The results from the two models are compared and a method to select an appropriate model in general is proposed.