Widespread application of steel metal sheets in buildings, besides increasing architectural interests in the use of non-white colors, raised the idea to design the best coating for the steel sheets and evaluate both energy saving and thermal comfort in four test model buildings.. Experiments have been carried out in Swedish climate over Latitude 60°N with four steel sheet model buildings to evaluate the performance of low emittance coating for interior surface and high near infrared reflectance and high thermal emittance for exterior coatings in order to evaluate the possibilities to save energy for cooling during hot seasons and heating during cold seasons. Project has been initiated by SSAB Tunnplåt AB – and takes place in Borlänge, Sweden. Observation and results over different radiation and surface temperatures, indoor climate, energy demand and usage are included in this report. Conclusion includes thermal savings due to optical properties of interior/exterior surfaces, increase in mean radiation temperature inside building, energy consumption, demand peak shaving and comfort study. The result shows clearly that it is possible to save cooling energy by using roof and wall materials with high near infrared reflectance. During one week with warm and sunny weather, the electricity savings for cooling was 12% lower in the building with high near infrared reflectance for exterior coatings compares to normal exterior coating with the same visible color but with normal (low) near infrared reflectance. In applications with other cooling equipment (no fans running during periods with no cooling demand), the energy saving should be approx. 25%. The test equipments installed are prepared for measurements during cold season, but due to the period of this work (April-August 2007) no such test was performed.