Heating, ventilation and cooling of buildings are responsible for 30-40% of the energy consumption in buildings and a corresponding significant amount of CO2 emission. Since 2006 the European Energy Performance of Buildings Direc-tive (EPBD) is being implemented in building codes on a national level. Due to high energy consumption and often unacceptable indoor climate energy (noise, draught) some European countries do not recommended full air-conditionings. Alternatively, heating and cooling may be done by radiant heating and cooling systems, where pipes are embedded in the building structure (floors, cei-lings, walls) or in the centre of the concrete slab (Concrete Core Temperature Control). The present paper discuss the limitations and possibilities of radiant cool-ing systems in office buildings demonstrating the essentiality of a good and inte-grated building design to obtain an acceptable comfort level. Different office buildings with different dimensions of south windows are analyzed and their influence of internal comfort are compared
