Q: I changed the batteries in my smoke detector, but when I tested it afterward nothing happened. The batteries are new, but the smoke detector is very old. I know that it’s hard-wired into my ...

If your detectors are broken or very old, you should take the time to replace them. ... this Kidde Smoke Detector is a very affordable hardwired smoke detector with a battery backup.

Smart-home features: There are very few smart detectors on the market. ... If you get the same brand as your old smoke detector, you may be able to install it on the old wall bracket.