The answer to 'how much to replace furnace in Illinois' is that the cost to replace a furnace can vary significantly depending on several factors. Typically, the cost to replace a furnace in Illinois can range from $3,000 to $10,000 or more, depending on the size of the home, the type of furnace, and the complexity of the installation.
Factors that can influence the cost include the efficiency rating of the new furnace, the brand and model, whether any ductwork or electrical work is required, and the labor costs in your local area. It's important to get multiple quotes from licensed HVAC contractors in your area to get an accurate estimate for your specific home and needs.