Moisture control of the indoor climate in Skokloster castle Rickard Eriksson Moisture control aims to reduce the risks associated with high relative humidity (RH) to avoid the emergence and growth of mold. In historic buildings with little or no demand for thermal comfort there are, to lower RH, mainly three active climate actions. These are heating, dehumidification and adaptive ventilation. The methods have been used in Skokloster castle (an unheated baroque castle between Uppsala and Stockholm) for three years to enable decision making of what climate control strategy that can prevent mold growth in a energy efficient way. Each action lasted for a year in three different case study rooms. To see the effect of the actions, three reference rooms with no actions were used. Temperature and RH was measured for all years and rooms. In the case study rooms energy use was registered. The result shows that the need for active climate control has been low, which can be shown by studying the energy use. The energy use is generally low for all actions and should not be crucial for the future choices. The result is in many ways difficult to interpret, but it shows that it would be too risky not to apply moisture control in Skokloster castle. An important conclusion is that it is largely the exceptions that have navigated the equipment and that the exceptions therefore should navigate the choice of the climate control strategy.