The evaporation of binary droplets containing a mixture of two species with completely different physicochemical properties is important in many applications. This paper describes a numerical study of the heat transfer characteristics of a thin liquid film and an intrinsic meniscus in a sessile droplet of a binary fluid, 5.0(wt)% aqueous n-butanol solution, to analyze the influence of various factors on the heat transfer. The thin film was longer than for a water droplet and the heat and mass fluxes were greater. The droplet contact radius, wall superheat, contact angle, and the air in a closed environment can affect the contribution of the heat transfer in the thin film region on the overall heat transfer. The wall superheat has the greatest effect on the heat transfer followed by the droplet size, surface wettability, and non-condensable gas. These four significant effects can be efficiently combined to enhance the heat transfer in applications involving binary droplet evaporation.