This thesis conducted at the University of Uppsala investigateshow well a prefabricated building component from the manufacturerMasonite Lättelement AB can be incorporated into ahouse projected to accomplish the demanding criteria of a passivehouse. The thesis is organized as a comparison betweenthe prefabricated elements and an on-site built component fromthe passive house area of Oxtorget in Värnamo, Sweden. Theaspects investigated were air leakage, energy, moisture, economyand noise conditions.Results of the comparative analyzes shows that the prefabricatedproducts were capable of accomplishing the requirementsof passive houses and therefore this thesis should beviewed as a basis to confirm that the technology of prefabricatedbuilding components today in Sweden are mature enoughto be a significant part of the passive houses that are to be builtin the near future. The development of prefabricated technologyis of crucial significance if we are to accomplish the goalsof reduced energy consumption by the year 2020.