No, this is not necessary. The supplied hose for the condensation water is only needed in dehumidification mode. Then, however, be sure to direct it into a large kettle (min. 5 litres) when it dehumidifies through the night, the unit is very effective. Have two of them, and am very happy with the cooling function and the dehumidifying function, especially after summer storms when the air is hot and humid. Would definitely buy it again!