Hardwired alarms also receive their power from your home, and only use batteries as backups. Standalone detectors run on batteries alone, so they may need to be replaced more often, and cannot signal each other in the event of an emergency Nest's and OneLink's alarms are an exception to this. However, it's a lot easier to mount standalone smoke detectors where you need them. Today's best Nest Protect deals?$115. 99View$119View$127. 65ViewLow Stock$127. 90ViewShow More DealsWe check over 130 million products every day for the best pricesEditor's Note: Black Friday is upon us, and that means smart home deals galore. From Nov. 21 to Nov. 28, you can save $20 on the Nest Protect and other Nest products through the Google Store. It's important to have at least one, if not more, working smoke and carbon monoxide detectors in your home or apartment.