This European Standard establishes requirements for determining, in accordance with a standardized procedure, the sound power level emitted into the surrounding air by air conditioners, heat pumps, liquid chilling packages with electrically driven compressors when used for space heating and/or cooling, including water cooled multisplit systems, as described in EN 14511 and dehumidifiers as described in EN 810. It is emphasized that this measurement standard only refers to airborne noise. This European Standard offers ways to determine the sound power level of units. Some of them are specifically adapted to provide results with low uncertainties, by using laboratory class acoustic methods and highly controlled working conditions. Those measurements are suitable for certification, labelling and marking purposes. In some cases, the target and/or the environment of the measurements do not allow such precision-class methods. This European Standard also offers ways to assess sound power levels with acceptable accuracy even though acoustic methods and/or working conditions are not laboratory-type, e. g. in situ or quality control measurements. This European Standard gives two classes of measurements and results, according to the test environment: Class A measurements correspond to controlled working conditions (standard or application rating conditions). It is defined by the respect to the tolerances of Table 2; Class B measurements correspond to the case where the range defined by the tolerances of Table 2 cannot be fulfilled. In both classes, precision or engineering class acoustic methods should be applied. The choice of the acoustic measurement method is done in accordance with EN ISO 3740 and EN ISO 9614 depending on the type of surrounding acoustic fields (diffuse or free field, enclosed or open space), and the available instrumentation. Whatever the current working conditions, the reference of acoustic standard shall be reported, with explicit mention of its accuracy class. NOTE 1 The use of EN ISO 3746 and EN ISO 3747 as survey grade methods are not recommended due to the high level of uncertainties. Their use is only allowed for non controlled environments. Three methods for determining the sound power levels are specified in order to avoid unduly restricting existing facilities and experience; the first methodology is based on reverberation room measurement (see EN ISO 3741, EN ISO 3743 and EN ISO 3747 in some favourable cases when the engineering grade can be fulfilled); the second method is based on measurements in an essentially free field over a reflecting plane (see EN ISO 3744 and EN ISO 3745); the third method is based on sound intensity measurement (see EN ISO 9614) in preferably free field environment. NOTE 2 The references in this European Standard to EN ISO 3743 should be understood as EN ISO 3743-1 or EN ISO 3743-2 as well. The necessity to regulate the test conditions obviously leads to recommend test methods implemented in acoustically designed (enclosed) spaces, such as EN ISO 3741, EN ISO 3743, EN ISO 3745 and also EN ISO 9614 when implemented in enclosed space. The open spaces should be covered only in specific cases, e. g. when the size or the power of the unit under test cannot be managed by standard test rooms. Suitable test methods are EN ISO 3744 and EN ISO 9614. NOTE 3 Intensity measurement methods are quite robust and are well suited for tests to be done in environments without or with a light acoustic treatment (the better the acoustic treatment, the easier the implementation).