Two physics modules, the optical heat flux approximation and the photon volume emission, of the Heat flux Engineering Analysis Toolkit (HEAT) have been experimentally validated on ASDEX Upgrade. For validation of both modules, two dedicated tiles are selected: One is taken from the outer divertor target, where it is intersected by the strike line, and one is taken from the private flux region, which is an area only exposed to radiation. Three pulses [L-mode, Type-I ELMy H-mode, and quasi-continuous-exhaust (QCE) H-mode] have been chosen for this validation task. Infrared-based heat flux profiles and thermocouple-based temperature profiles have been compared against the HEAT simulations. Any input required for HEAT is deduced from dedicated experimental results. Whereas for the L-mode case, perfect matches between the experimental data and HEAT results can be achieved easily, for the H-mode case, the situation requires a deeper look into the underlying physics to obtain good agreement. In the case of the Type-I ELMy H-mode, this is related to the non-consideration of edge-localized modes in these HEAT simulations. For the QCE H-mode case, this result seems to be connected to a broadening of the power fall-off length because of the presence of enhanced radially directed filamentary transport. In both of these situations, HEAT can be used to identify a discrepancy between the experimental data and the physics models, to quantify the magnitude of this discrepancy, and to provide insight into the energy sharing between various transport channels.