Abstract: A portable inflatable heating, ventilating and air conditioning duct apparatus includes a bladder made of resilient material for expansion and contraction. The bladder has a small opening for the movement of air in and out of the bladder. An elongate flexible hose is connected at one end with the small opening on the bladder. An air pump is positioned at the opposing end of the elongate flexible hose for supplying air under low positive pressure to the bladder for expansion of the bladder. A manually operated valve is positioned between the air pump and the bladder for preventing the escape of air from the bladder, unless same is desired. The apparatus further includes direction stabilizing apparatus for allowing the flexible hose to push the bladder through a segment of the HVAC duct in which the apparatus is positioned.