Abstract: An atomizing humidifier nozzle and connected solenoid operated valve are secured as a unit to a box through an adjustable connection which allows the nozzle to assume various angular positions in one plane forwardly of the box as where the nozzle is projecting into a warm air furnace plenum. A thermostat on the forward face of the box is exposed directly to the heat of the plenum. A stepped flange on the forward face of the box along one edge thereof cooperates with a mounting strip bridging an opening in a wall of the furnace plenum to form a convenient hinged connection between such wall and the box, allowing the box to be swung to an inspection and maintenance position. The box can be indexed in ninety degree increments on the plenum wall by relocation of the mounting strip to provide universality in the positioning of the humidifier nozzle on various furance and plenum configurations.