Nightcooling: practical experiences in offices and the need for standard implementationinto energy performance legislations

Nightcooling is worldwide promoted as an effective tool to reduce cooling demands. However, it is clear that as long as the potential of nightcooling is not standardintegrated into energy performance calculations of buildings, its application will be strongly hampered. Firstly, practical experiences with nightcooling in an office are discussed. Secondly, it is found that of the countries analysed, only in the French energy performancelegislation (RT2005) the effect of a nightcooling system can be taken into account without the need of the principle of equivalence. Finally, the implementationof nightcooling into the energy performance legislationis discussed.