In order to develop various parts and components of electric vehicles, understanding the effects of their structures and thermal performance on the energy consumption and cruising distance is important. However, such essential and detailed information is generally not always available to suppliers of vehicle parts and components. This paper presents the development of a simple model of the energy consumption by an electric vehicle in order to roughly calculate the cruising performance based only on the published information to give to suppliers, who otherwise cannot obtain the necessary information. The method can calculate the cruising distance within an error of 4% compared to the published information. The effects of the glass and body heat transfer characteristics on the cruising performance in winter were considered as an example application of the proposed model. An anti-fog control method was modeled, where the relative humidity around the front windshield was assumed to be detected and the recirculation ratio of the ventilation was controlled in order to maintain defogging. The effect of the anti-fog control combined with the thermal insulation efficiency of the glass on the cruising performance was examined with the cruising distance estimation method. The results indicated that improving the thermal properties of the glass does not have much effect without the anti-fog control. Hence, anti-fog control enhances the effect of improving the thermal properties of the glass on the cruising distance.