In Europe, summer heat waves are becoming harder to bear. The demand for air conditioning is on the rise, especially in office buildings. Yet buildings alone represent 40% of the EU's energy consumption, and air conditioning accounts for a significant part of it. In addition, air conditioning produces greenhouse gas emissions, aggravating global warming and putting at risk European climate protection commitments. The solution: reduce the energy requirements of existing air conditioning systems and change the way buildings are designed and used to achieve sustainable summer comfort without active cooling.