Abstract: A hot air burner in which a nozzle assembly is comprised of an inlet port housing (8) incorporating an internal plenum chamber (18) into which is introduced a flow of compressed air via an inlet port (4) in the inlet housing (8). The flow of compressed air is controlled by the width of an adjustable gap created between a frusto-conical exterior surface (20) of the internal annular chamber (18) and the internally chamfered wall (22) of a mixing tube (12). Turbulence in the compressed airflow is created as the air enters the mixing tube (12) and this swirling effect promotes efficient mixing of subsequently introduced combustible gases to tile mixing tube (12) via an inlet port (6) in the inlet housing (8). The combustible mixture is ignited and the resultant combustion contained within the confines of an outer burner tube (10). The flame front is contained within the burner tube (10) and extends approximately six inches into the length of the tube (10).