The temperature of the subsoil, the heat source that comes directly from the earth, the technology that allows it to be transformed into energy. Renewable, clean, safe geothermal energy is a functional, efficient and sustainable energy production system. Not only for heating, but also for cooling and producing hot water for domestic purposes. Natural ground heat supplies a heat pump through the air sensor probes and the ground exchange circuit. It does so constantly throughout the year, because the temperature of the subsoil is not affected by seasonal changes, thus limiting the fluctuations that are inherent in many renewable energies.