This model is normally used in bathroom or toilet locations. It is designed to run permanently, using a very low power consumption and can optionally be boosted to a higher speed by the use of an external switch (not included). The constant volume technology automatically adjusts the speed of the fan to ensure the desired airflow is delivered. A silent high pressure axial impeller means Lo-Carbon dMEV can meet the requirements of many domestic installations without the need to use a traditional centrifugal fan.