This report outlines the key outcomes of research project RP1037u1 ‘Above-Roof Temperature Impacts on Heating Penalties of Large Cool Roofs in Australian Climates’, an extension to project RP1037 ‘Driving increased utilisation of cool roofs on large-footprint buildings’. The research has been focused on two key aspects of roof thermal performance that had, up until the time of writing, not been taken into account in most investigations into cool roof technology: 1. The condensation and evaporation of dew on the roof surface, and the effect this has on roof temperature by way of: a. The latent heat that is absorbed and released; and b. Any change in the effective radiative-optical properties of the roof top surface due to accumulated water. 2. The effect of roof temperature on above-roof air temperatures, and the influence this can have on the performance of rooftop heating, ventilation and air-conditioning (HVAC) equipment. A review of relevant literature (included in this report) did not reveal any previous studies that had investigated both 1a and 1b, above.