The answer to 'how much to replace water heater in Illinois' is that the cost to replace a water heater can vary significantly depending on several factors. Generally, you can expect to pay between $800 to $1,500 for a basic water heater replacement, including the cost of the unit and installation.
The final price will depend on the size and type of water heater, the complexity of the installation, and any additional repairs or modifications needed to the plumbing or electrical systems. Factors like the brand, energy efficiency, and any special features of the water heater can also affect the overall cost. It's essential to get local quotes from licensed HVAC professionals to get an accurate estimate for your specific situation.