The answer to 'how much to replace carbon monoxide detector in Illinois' is that the cost can vary widely, typically ranging from $20 to $100 for a basic replacement unit. Factors that influence the price include the type of detector (battery-powered vs. hardwired), the brand and features, and whether you need to hire an electrician for installation.
It's important to note that replacing a carbon monoxide detector is not a DIY task, as it often requires electrical work. For safety reasons, it's best to hire a licensed and insured electrician to handle the installation. They can ensure the new detector is properly wired and integrated with your home's electrical system.