The answer to 'how much to replace air duct sealing' is that the cost can vary significantly depending on several factors. In general, the typical range for professional air duct sealing replacement is between $500 to $2,000 or more, depending on the size of your home, the accessibility of the ductwork, and the extent of the work required.
The main factors that influence the cost include the square footage of the ductwork that needs to be sealed, the complexity of the ductwork layout, the materials needed (sealants, tapes, etc.), and the labor required. Homes with older, harder-to-access ductwork will generally cost more to seal than newer, more accessible systems. Additionally, any necessary repairs or replacements to the ductwork itself will add to the overall cost.