The purpose of this degree project is to design an office hotel that can be converted into a residence. Suggestions for floor plans where only minor remodeling is required when converting are developed. Furthermore, the building must reach the energy requirement for a zero-energy building. Through a literature study where current laws and regulations are presented for the two uses, the buildings can be designed according to the wishes of the contractor and the future users. The result was two buildings; a main building and a mobile modular house. The roof of the main building holds 72 m2 of solar cells mounted to south, west and east. These are not enough to meet the energy requirements for zero-energy buildings when the building is used as an office- additional solar cells are required. When the building is used as a home, energy consumption and electricity production are equivalent. It is possible to design flexible buildings that can be used both as offices and residence without major renovations. Reaching the energy requirements for this building was more difficult despite the fact that solar cells with good efficiency were used in the calculation.