The average cost of replacing an HVAC system is $7,000, with an average range of $5,000 to $10,000. Depending on the brand and size, this corresponds to $25 to $60 per square foot of cover.
An HVAC system with ducting costs between $5,000 and $12,500 to install. You'll pay extra if you purchase a separate furnace and air conditioner. Compared to a few hours for replacement, installing a new system with ducting may take days. The majority of that time is spent installing new ducts and vents, which may include cutting through walls.