Abstract: Apparatus for saving heat which is otherwise wasted particularly in multi-story buildings. The apparatus in one form includes first, second, and third elongated hollow members which are disposed for at least an axial section in coaxial relationship. The first or central elongated member carries smoke and waste heat away from a heating apparatus such as a furnace. The second and third elongated members are in fluid communication with each other. The second elongated member in one form of the invention is also in fluid communication with an air inlet disposed on one floor of the associated house. The third elongated member is also in fluid communication with another floor of the associated house.