The energy used in building technology represents a significant factor in operating costs. Builders of new residential buildings are therefore increasingly opting for an energy-saving concept consisting of geothermal heat recovery combined with controlled ventilation of the living space. The HEKATHERM-EWT system is based on an air/geothermal heat exchanging pipe made of PE, which distributes the fresh, preheated air throughout the building via downstream ventilation pipes after it has passed through the cross heat exchanger. Suitable chamber and fitting components are available to adapt the EWT ventilation system to the respective building measure.