The answer to 'how much to fix HVAC system in Illinois' is that the cost can vary widely depending on several factors. Typical HVAC repair costs in Illinois can range from a few hundred dollars for minor issues up to several thousand dollars for more complex problems or full system replacements.
The exact cost will depend on factors like the type of HVAC system, the extent of the repairs needed, the age and condition of the equipment, your location within Illinois, and the rates charged by local HVAC contractors. It's important to get multiple quotes from reputable local HVAC companies to ensure you get a fair price for the work required.