The study presented in this report has been performed for Nordsyn sponsored by the Nordic Council of Ministers. The aim of this study was to analyse if the information given on the energy labels of air-to-water heat pumps give consumers in Nordic countries sufficient information on energy performance. When comparing results from field measurements to declared values, it shows the declared values are usually better than the field data, especially in countries with humid climate. There could be several reasons for this deviation as non-optimal installations, bypass of control systems, old field data etc. The suspicion that the deviation is due to that the standard tests do not take humidity sufficiently into account could not be proved nor fully dismissed. Recommendations are given on how this could be further investigated, including field measurements in Nordic countries.