Google Nest Protect Smoke and Carbon Monoxide Alarm (Battery, 2nd Gen)
A smart smoke and CO alarm with phone alerts and voice warnings, but Google stopped making it in 2025, so check the manufacture date before you buy.
Updated
- Smoke and CO alarm in one unit, battery powered
- Phone alerts and voice warnings
- Silence alarms from the app or the button
- Google stopped making it in 2025; existing units keep getting updates
- Expires 10 years after the manufacture date, not the purchase date (Google)
Best For / Not For
Best for
- Google Home households adding to an existing set of Nest Protects
- Buyers who want phone alerts for smoke and CO while away from home
Not for
- Anyone starting a new smart alarm setup (Google points to a First Alert model as the replacement)
- Buyers who don't want to check a manufacture date before installing
Key Details
What Discontinued Means Here
Google stopped making the Nest Protect in 2025. Google's support pages say existing alarms keep working as before through their expiration dates and keep receiving software and security updates. So it is not unsafe to buy, but it is a product at the end of its line.
The bigger issue is the clock. Google says the 2nd-generation Nest Protect must be replaced 10 years after its manufacture date, not the date you buy it. Check the date on the box or the back of the alarm when it arrives; if it is several years old, return it.
Who Should Still Consider It
If your home already has Nest Protects and you want one more that works with them, a new unit with a recent manufacture date makes sense. For a new setup, Google itself recommends the First Alert SC5, which fits the Nest Protect mounting plate.
Pros and Cons
Pros
- Only alarm here that sends smoke and CO alerts to your phone
- Spoken warnings instead of only beeping
- Covers smoke and CO in one device
Cons
- Discontinued by Google in 2025; new stock is whatever is left
- Its 10-year life counts from manufacture, so a unit that sat in a warehouse has less time left
- Expiry reminders in the app only work if the alarm is on Wi-Fi and set up in the app
Bottom Line
Consider the Google Nest Protect only to extend an existing Nest Protect setup, and check the manufacture date first. For a CO alarm on its own, the Kidde KN-COP-DP-10YL or First Alert CO710 is the simpler choice.
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