How do I know if I have existing hardwired alarms?If your existing smoke alarms have the wording “240V” on the back of the alarm they are likely to be hardwired.If there is a solid green or red light on the alarm they are likely to be hardwired.If there are cables coming out of the back of the alarm into the ceiling cavity they are likely to be hardwired.Pro Tip: Search the model number online to see if it is a hardwired alarm.If in doubt always check with a licensed electrician. Already have hardwired alarms? Here’s what to do:Replace all existing hardwired alarms in your home with new GT hardwired modelsAny additional locations can be GT 10-year battery (wireless) modelsWe'll send the GT Smoke Alarms to you already interconnected as a group.Please note, an electrician will be required to install GT hardwired smoke alarms.