Google Nest Protect Smoke Alarm Lifespan: What You Need to Know

The Google Nest Protect smoke alarm has been discontinued since 2025, but many are still in use. The lifespan of this device varies, but a second-generation Nest Protect typically lasts for 10 years from its manufacturing date. This is a standard timeframe for smoke and CO sensors to reach the end of their useful life.

Before it expires, your Nest Protect will send you a push notification three months in advance. If you don't replace it after the expiration date, the alarm will start chirping continuously. Some users have reported issues with a shorter 8-year lifespan for certain units.

If you're looking to purchase a new Nest Protect, be aware that sealed devices can cost up to $200 on eBay. However, there are alternative smart smoke and CO alarms available, such as the X-Sense SC07-MR, which offers professional monitoring and compatibility with Home Assistant.