The answer to 'how much does system upgrade cost' is that the cost can vary widely depending on several factors. Typically, a full HVAC system upgrade can range from $4,000 to $12,000 or more, including the cost of the new equipment, installation, and any necessary ductwork modifications.
The specific cost will depend on the size of your home, the efficiency and capacity of the new system, the complexity of the installation, and your local labor and material costs. Upgrading to a higher-efficiency system may also qualify for rebates or tax credits, which can help offset the upfront investment.