The answer to 'how much to replace carbon monoxide detector in Chicago' is that the cost can vary widely depending on several factors. Typical ranges for a basic replacement can be anywhere from $30 to $100 or more, depending on the type of detector, the complexity of the installation, and whether you hire a professional electrician or do it yourself.
Factors that influence the cost include the type of detector (battery-powered vs. hardwired), the brand and features, whether it needs to be integrated with your home's electrical system, and the labor costs in your local area. Hiring a licensed electrician will generally cost more than a DIY installation, but can ensure the work is done safely and up to code.