This paper describes numerical simulations of the non-isothermal, laminar flow of Newtonian and non-Newtonian liquids inside rotating cylindrical cans containing a headspace air bubble. Two modes of rotation are considered: axial rotation about a horizontal axis and end-over-end rotation. The rotational speed is held constant so that once initial transients have decayed the flow field in both cases is periodic. The aim of the numerical simulations, carried out using the ANSYS CFX computational fluid dynamics software, is to compare liquid heating times for different flow conditions. To reduce computational run times the calculations are carried out for a liquid with an artificially high value of thermal diffusivity. For axial rotation the simulations have been carried out using 2D and 3D models and it is shown that a 2D model can identify trends in heating times. In both end-over-end and axial modes, rotational speeds and radii of rotation are identified which minimize the heating time. The conditions are shown to correspond closely to those which maximize a measure of mixing in previous studies of isothermal flow.