The answer to 'how much to fix furnace in Illinois' is that the cost can vary widely depending on several factors. In general, the average range for furnace repair in Illinois is typically between $150 to $800, but the exact price will depend on the specific issue, the age and model of the furnace, and your location within the state.
Some of the key factors that influence the cost of furnace repair include the extent of the problem (e.g., a simple repair vs. a major component replacement), the labor rates in your local area, and whether any additional parts or equipment are needed. It's best to get quotes from multiple HVAC contractors in your area to compare prices and find the most affordable solution for your needs.