This standard specifies the minimum requirements for the thermal insulation of building components and in the area of thermal bridges in the building envelope of buildings. The requirements for the minimum values of thermal resistance apply to: - all rooms that are heated to a target room temperature of at least 19 °C in accordance with their intended purpose; - all rooms that are heated to a room setpoint temperature of at least 12 °C and less than 19 °C according to their intended purpose; - as well as for rooms that are heated by the aforementioned rooms via a room network. The requirements for minimum thermal insulation in the area of thermal bridges apply to - all rooms that are heated to a room setpoint temperature of at least 19 °C according to their purpose; - as well as for rooms that are heated by the aforementioned rooms via a room network. This document specifies the requirements for thermal insulation instructions for the planning and construction of common rooms in buildings. The requirements apply to buildings under construction, to extensions of existing buildings and to new building components such as the closing of window openings in existing buildings. Further specifications, e. g. occupational health and safety, are not affected by this standard. The requirements for summer thermal insulation (Section 8) apply to habitable rooms.