Electrification of mobile machines requires focus on reducing unnecessary energy consumption, which is essential to avoid the need for oversized energy storage. Waste heat recovery of already existing heat flows in the vehicle, such as the working hydraulic system, is a promising way of reducing the energy consumption needed for keeping the cabin warm in the winter. This paper presents a model of a heat recovery concept from the working hydraulic system to the cabin, different from the ones typically seen in the literature. The model is created with the open-source tool OpenModelica together with the DLR Thermofluid Stream library. Focus of the model was to analyze how the dynamic characteristics of the working hydraulic system affects the cabin temperature, and to evaluate the waste heat performance. The results show that the cabin temperature fluctuates close to detectable variations without any interference of active temperature control, and also indicates promising cabin heating performance even under lower operation intensities.