The requirements to build environmentally friendly become harder by every year. One of tomorrow’s eco-friendly apartment buildings is built in Hamburg Germany. The building is called Woodcube and consists mostly of prefabricated solid timber elements with very unique features. No nails, glue, finishes or environmentally harmful substances are used in the construction. There are only a few materials besides elevator shaft and basement made of reinforced concrete that is not derived from biological materials.A building physical examination was performed in which the Woodcube project was studied from an energy and a moisture – point of view. This was done with help from a number of computer based tools in which energy consumption, moisture levels and mold growth were analyzed. The building was placed at three different locations in Sweden corresponding to one city in each climate zone I, II and III, where later simulations were performed. These three locations chosen were Kiruna, Karlstad and Kalmar where series of measured climate data were available. The latest requirements from Boverket were compared with the calculated values from the simulations.Earnings from the energy simulations showed that the requirements with respect to specific energy and the climate screen average heat transfer coefficient were fulfilled with district heating as the heating method. When electric heating was used as the heating method the requirements regarding specific energy were not fulfilled. Two other heating methods in addition to electricity heating which both are defined as electric heating were studied. These were geothermal heating and an air-water heat pump. The requirements with respect to specific energy consumption were then fulfilled due to the higher assumed heat factors (1.6 and 2.9) compared to the electricity heating (1.0). In addition for electricity heating, there are requirements for the maximum installed power for heating depending on the area of heated surface. This value was not exceeded for any of the resorts.Moisture simulations were made for two different parts of the building, the exterior walls and the roof of the building. With the help of detailed drawings of these building components and material data, realistic moisture simulations could be made. The results from these simulations showed that there will be no major moisture problem in either the exterior walls or the roof. For the exterior walls the results from the simulations showed that there was a risk for some mold growth on the untreated façade of larch because of the high calculated relative humidity. The results also showed high moisture content in the façade of larch increasing the risk of rot. ForVIthe roof the results from the simulations showed high relative humidity at the roof’s surface and a couple of inches into the roof structure. The high relative humidity in the roof was disregarded because of the non-biological materials with less mold growth.