Abstract: An air to air heat exchange system for removing undesirable air from an enclosed structure. The heat exchanger provides for the removable of air containing pollutants, toxics gases and odors while providing for the recovery of heat from the exhaust air. The system utilizes a plurality of tubes within a larger tube so that air can flow freely over and around the smaller tubes thus providing for maximum heat transfer between the incoming air in the smaller tubes and the exhaust air in the larger tube. The smaller tubes, if used for the incoming air, permit the air to be distributed to various selected locations throughout the structure.