ECFanGrid retrofit in the 5-star hotel INTERCONTINENTAL BERLIN: Four old ventilation systems were equipped with the latest EC technology during the renovation of a large conference room. ECFanGrids were used in various arrangements, always optimally adapted to the existing cross-section of the existing AHU. The technical rooms in which the AHUs are located were very cramped. Due to the compact design of an ECFanGrid Retrofit, the upgrade was nevertheless easily implemented.