JPH05346261

PURPOSE:To retain an appropriate humidity by controlling the revolution number of a fan in response to the output of a dew point temperature detecting means and the output of a surface temperature detecting means. CONSTITUTION:A surface temperature detecting means 9 detects the surface temperature of a radiant panel, and a dew point temperature detecting means 10 detects a dew point temperature in a room where an indoor unit 5 is installed,. The outputs of the surface temperature detecting means 9 and dew point temperature detecting means 10 are input in a control means 11, and the control means 11 controls the revolution number of a fan 12. That is, the revolution number of the fan 12 is changed by an inverter conforming to the temperature difference by comparing the dew point temperature of the indoor air and the surface temperature of the radiant panel by a temperature comparator of the control means 11. Therefore, it is controlled in such a manner that the surface temperature of the radiation panel is always kept higher than the dew point temperature of the indoor air. By this method, moisture condensation does not generate on the surface of the radiant panel.