Abstract: A heat convection barrier particularly adapted for use with greenhouses and warehouses consists of a series of inflatable tubes which are suspended beneath the roof of a structure and inflated into contact with each other to form a barrier against heat loss through the roof. Each of the tubes includes an integrally formed seam by which the tubes are suspended beneath the roof and an inflatable main body portion, and the tubes are spaced from each other a distance less than the inflated diameters of the main body portions so that when they are inflated they contact each other and form a continuous barrier. One end of each of the tubes is tied off and the opposite ends are split and wrapped about an apertured conduit and a low pressure fan or blower communicates with one end of the conduit to inflate the tubes.