The aim of the study was to develop improved measurements on heat pump performance. A model-based approach was combined with data fusion technique to estimate performance of a heat pump. These improved heat pump performance measurements implied fused measurement between direct and indirect measurements of compressor power and condenser load. Developed models of compressor power and condenser load used input data from building energy management system to produce measurements on the heat pump performance. The direct measurements were obtained by using the temperature and pressure measurements, while the indirect measurements were obtained using the electrical signal of the heat pump part load. The results showed a big need for use of different data sources to define real energy performance metrics. Further, the analysis on obtained measurements showed that indirect and fused measurements were more reliable than only direct measurement, particularly for the condenser load. Use of only direct measurements could result in higher estimation of electricity and heating energy consumption than the real consumption is. The analysis of fused measurements on the heat pump performance showed that such improved measurement could enhance heat pump performance verification. (C) 2010 Elsevier B.V. All rights reserved.