The answer to 'how much to replace smoke detector' is that the cost can vary widely depending on several factors. As a general range, most homeowners can expect to pay between $50 to $200 to replace a single smoke detector, including both the device and professional installation.
The exact cost will depend on the type of smoke detector, whether it's hardwired or battery-powered, the complexity of the installation, and your location. Factors like the brand, features, and whether you need to replace the entire unit or just the batteries can also impact the price. It's best to get quotes from local electricians or home service providers to get an accurate estimate for your specific situation.