When the heat or cool water is produced by the Heat Pump (according to the season), it circulates in a network of isolated pipes which comes to feed the Fan Coil. The presence of a ventilator is to grant a better distribution of the heatness or the coolness in all the rooms. This type of transmitter allows to manage the comfort in each of the rooms. It also presents the advantage to filter the internal air of your home and to dehumidify in summer. There are devices for wall mount, ceiling mount, and "cassettes" embedded in false ceilings. These devices are mostly used in office buildings and hotels.