There is a great variety of prefabricated detached single family homes from many differentcompanies in Sweden today. Traditionally they have competed primarily with either a low price tagor great freedom in design. Rising energy prices and the tougher energy requirements set by theSwedish National Board of Housing, Building and Planning has made low power consumption a newimportant competitive factor.Englundshus is a company in Kalix who prefabricate single family homes. In the EU projectNorrlandshuset they cooperated with suppliers in the Kalix region to develop an energy-efficientdetached house. This thesis was carried out in parallel with the project and has applied the criteriafrom the project to the case study. The case study includes developing a detached house classified asa minienergy building, which can be produced efficiently in Englundshus factory. First, all theconditions and requirements were collected, and then a house was designed based on those.The designed house is a detached single family home with two floors, space-efficient floor planningand two different versions of façade design. The results show that the established energyrequirements are difficult to achieve with the wall construction proposed by the housemanufacturer, even though the house had been designed according to the principles of energyefficiency. A more precise execution of airtightness and a building envelope with higher performanceis required to be able to fulfill the requirements.