Abstract: A modular heat exchange system for use in a central heat exchange installation in buildings, including at least one heat exchange element equipped for exchanging heat between environmental air and a fluid which is conducted through the heat exchange element. The heat exchange element has a predetermined first shape with opposite lateral sides. At least one non-heat-exchange add-on element, equipped for adding a given additional functionality to the system, has a predetermined second shape with a complementary lateral side to one of the opposite lateral sides of the heat exchange element.