The answer to 'how much to replace ductless system in Illinois' is that the cost to replace a ductless HVAC system can vary widely, but typically ranges from $3,000 to $10,000 or more. The exact cost will depend on factors like the size of your home, the complexity of the installation, the brand and model of the ductless unit, and your location within Illinois.
Ductless systems, also known as mini-splits, are an efficient and flexible heating and cooling option, but the upfront cost is generally higher than traditional ducted systems. It's important to get multiple quotes from licensed HVAC contractors in your local area to understand the specific costs for your home.