The article presents the experimental study of a heat pump possessing solar collectors as an energy source. A method to test the combined work of collectors delivering heat to the evaporator of a heat pump was devised. The layout of the test facility is shown and the system construction with the measurement equipment is described. The planning experiment to test the installation was chosen. The medium fluid condenser temperature (t) over bar (c), the fluid condenser mass flow rate m(c) and the medium fluid evaporator temperature (t) over bar (ev) were chosen as experiment factors to determine both objective functions-the coefficient of performance (COP) of the heat pump and the efficiency of the system eta(s). The reverberation of both objective functions is shown. (C) 2007 Elsevier Ltd. All rights reserved.