Ice accretion on aerodynamic surfaces introduces a number of issues related to aircraft. Such issues include a rapid increase in drag, a decrease in available lift, increased noise and vibration, and a great increase in flow unsteadiness. The interplay between a growing layer of ice roughness and the resulting increase in surface heat transfer rate is a physically complicated process. Heat transfer mechanisms are thought to become increasingly important as the ambient temperature approaches the freezing temperature of water from below (often called the “glaze icing” regime). This paper details a computational investigation into the heat transfer rise associated with ice accretion from a physical perspective. The ability of a modern Computational Fluid Dynamics (CFD) code to calculate the heat transfer rise associated with ice roughness is explored via comparison with experimental data from NASA and from the Penn State Adverse Environment Rotor Test Stand (AERTS). Experience gained from simulating these geometries is used to develop physical understanding of some of the diffculties associated with simulating heat transfer on ice-roughened airfoils.