Among the ongoing research projects at SERC (Solar Energy Research Center) there is one Nordic collaboration project called REBUS (Competitive Solar Heating Systems for Residential Buildings). The objective of this project is the development of competitive solar heating systems for residential buildings in northern latitudes. This is part of a European wide collaboration for developing the next generation of solar thermal systems. The project partners are located in Riga, Copenhagen, Lund and Oslo, where country specific conditions for the development of the systems are taken into account. This thesis project was carried out at department of physics in University of Oslo (UiO) in Norway and Högskolan Dalarna SERC in Sweden. Solar system developing company SolarNor has collaboration with the prefab-house manufacturer Systemhus for the integration of solar heating systems. Norwegian company Systemhus has designed new series family houses named Karakter. There are several types of low energy houses. Karakter type 3 and Karakter type 4 is interested in install solar floor heating system, and most studied in this thesis work. The results of modeling are used to draw conclusions for design of the heating system and the optimal orientation of the building as well as the placement of the façade integrated solar collectors. The purpose of this thesis work is to modeling and heat demand calculations for type houses and adoption of the SolarNor solar heating system for those houses. The energy consumption of these buildings has been investigated by modeling the buildings simulation with computer software IDA /1/ and Prebid /2/. For adoption of the SolarNor solar collector, SolDat simulation program has given the valuable results of the façade integrated solar collectors. Through the energy calculation and economic evaluation, 21 m2 collector area installing on southern façade 4 is recommended for the optimal adoption of SolarNor solar collector for Karakter types houses