A home's smoke detector is often one of those things. Like the smoke detector's green light. The green light on a smoke detector can mean a few things, and though not every smoke detector is the same, it generally doesn't mean anything is wrong. If your smoke detector is connected directly to your home's electrical system — what we call hardwired — a solid green light simply means that it has a good connection to the power source. If you have a smoke detector that is battery-powered, it will often use a blinking green light to indicate the same thing.