In the beginning of 2008 the new Dutch standard NEN 5060:2008 (NEN,2008) was published (status is still ‘preliminary’). The standard contains four new weather data files for various applications. The files are intended as replacement for the commonly used defacto standard "De Bilt 1964/1965", which is used as a reference year for building performance simulation in the Netherlands. The Royal Dutch Metrological Institute (KNMI) has defined four possible future scenarios for the expected climate change. The weather data files according to NEN 5060:2008 and the KNMI-future scenario’s are combined into future weather data files for the use with building performance simulation program VA114 (Vabi, 2008). A study of an office building with a "top-cooling" concept shows the first experiences with the use of this weather data to determine the future building performances regarding energy consumption and indoor thermal comfort. It was found the future data sets can well be used for a robustness assessment of integrated building concepts. Over 30 years for the most extreme scenario a 70 % higher peak cooling load is needed to reach a similar comfort level as in the original situation.