The answer to 'how much does replacement cost in Illinois' is that the cost of HVAC system replacement can vary significantly depending on several factors. While there is no one-size-fits-all price, homeowners in Illinois can typically expect to pay anywhere from $4,000 to $12,000 or more for a full HVAC system replacement.
The specific cost will depend on the size of your home, the efficiency rating of the new system, the complexity of the installation, and whether any ductwork or other components need to be replaced as well. Older or larger homes, or those requiring more extensive work, will be on the higher end of that range. It's important to get quotes from multiple local HVAC contractors to understand the costs in your specific area.