Mobile buildings consume less energy compared to traditional stable buildings in pre-construction, construction, occupancy/maintenance and recycling stages in terms of lifecycle. The reduction of the energy consumption of the houses during their lifecycle is going to play an important role in the decrease of fossil fuel consumption. The purpose of this study is to develop a model to guide designers in terms of designing mobile buildings for the production of energy efficient buildings that do minimum harm to the environment, are suitable for climatic data, use renewable energy sources and are flexible for user needs that grow or decrease in size. The proposed mobile building is a single story energy efficient house in Istanbul for four people, which is developed by examining modern mobile building models. The building's design process was examined in detail including general design decisions and the effective use of energy, water, and materials. The building envelope alternatives created during this process were analyzed with Autodesk Ecotect Analysis 2011 software and according to the data obtained from the simulation program the final building envelope that decreases energy consumption has been identified. This final building envelope's energy loads are designed to be met with solar energy systems like photovoltaics and solar panels. Decreasing the energy consumption of houses during their lifecycle with energy efficient mobile building design was the aim of this study.