The Renewable Energy System for Residential Building Heating and Electricity Production (RESHeat ) system is a typical application of the utilisation of sun-tracked Photovoltaic Thermal (PVT) panels and underground heat storage units. This work introduces a MATLAB simulation model coupled with moisture and heat transfer processes. Validation of the proposed model from experimental measurements was conducted. The simulations were performed for a single year of RESHeat system operation for demo sites located in Cracow City. Results showed that the relative error between calculation and measurement varies from 0.258 % to 5.829 %, along with the same temperature trend. A Control Volume method is used to simulate coupled heat transfer in the ground.