Results of a directivity analysis for a heat pump demonstrator with low noise emission, the directivity of the sum level dominates towards the rear and front. The difference is approx. 5 dB to the sides. The directivity of the level-determining component of the 3.15 kHz one third octave band is more complex with a maximum in the left-rear direction (angle of approx. −150^°). (a) Test setup for directivity analysis with 24 additional microphones on a circular measuring surface (cf. Fig. 11) and an angular distance of 15^°. (b) Directivity characteristic of the overall sound power level and the level-determining one third octave band 3.15 kHz on the basis of a run out measurement at condition A7W55, 1 s time blocks from maximum to minimum heating capacity. The arrow describes the direction of the air flow, the compressor symbol the position of the machine room with the refrigerant circuit.