The answer to 'how much to replace system upgrade in Illinois' is that the cost can vary significantly depending on several factors. Upgrading or replacing an HVAC system is a major home improvement project, and the total cost will depend on the size of your home, the type of system being installed, the brand and efficiency rating, the complexity of the installation, and your location within Illinois.
As a general guideline, a full HVAC system replacement in Illinois can range from $5,000 to $15,000 or more. Higher-efficiency systems and more complex installations will be on the upper end of that range. It's essential to get multiple quotes from reputable local HVAC contractors to understand the specific costs for your home and needs.