An engine-independent heater, particularly a space heater for automobiles comprises a housing which includes a combustion chamber and an antechamber which is tangentially connected into the combustion chamber. The antechamber receives a fuel and air mixture which is ignited in the antechamber and directed into the main combustion chamber. The construction includes the housing carrying an ultrasonic vibrator which is actuated in order to intermix air which is drawn into the housing for the vibrator with fuel which is directed against the vibrator so that the coolant air intermix has there delivered into the antechamber of the heater. The construction includes a nipple connection into the antechamber which sprays fuel from a proportioning pump into the vicinity of the ultrasonic vibrator.