12 with appropriate isolation from each other there is further provided a second shutter 15 which is open when air is fed into the heater box 12 a blower unit 16 has a housing 17 divided into two segments each having an air outlet port 18 a blower fan 20 driven by a blower motor 19 is secured within the casing 17 which also has an air inlet port 22 the heater box 12 is provided with a drain opening 23 formed therein and a pivot 24 received in an aperture 26 in a body casing 25 such that the heater box 12 is movable within a limited range and an air intake section is defined around the heater box 12 the blower unit 16 including the casing 17 the blower motor 19 and the fan 20 and the heater box 12 are accommodated within the body casing 25 the pivot 24 on the heater box 12 is movably secured in the body casing 25 such that the inclination of the bonnet 2 is easily adjustable over the body casing 25 there is disposed an atomizing fluid reservoir 30 containing a proper fluid generally pure water or utility water on the bottom of the reservoir 30 there are disposed an opening pin 33 for opening a valve 32 to a fluid supply tank 31 from which the fluid 29 is led to the reservoir 30 and a guide pin 36 for guiding a float 35 sensing the level of the fluid 29 in the reservoir 30 and slidably secured by the guide pin 36 an ultrasonic vibrator 38 excited by an ultrasonic oscillator circuit 37 is provided on the bottom of the reservoir 30 for atomizing the fluid 29.