The answer to 'average cost for ductwork' is that the typical cost range can vary widely depending on several factors. Ductwork installation and replacement costs are influenced by the size of your home, the complexity of the ductwork layout, the materials used, and your local market conditions.
In general, you can expect to pay anywhere from $3,000 to $15,000 or more for a full ductwork system installation or replacement. Smaller jobs like adding or replacing a few runs of ductwork may cost $1,000 to $5,000. The best way to get an accurate estimate is to have a local HVAC professional inspect your home and provide a detailed quote.