2nd generation

Nest Protect smoke + CO alarm


Choose Wired if your current smoke alarm is connected to power wires.

Otherwise, pick Battery.

Buy 2 and get free shipping
Ships in 1 business day.

Know more, worry less.

Get alerts on your phone.

Nest Protect sends a message when there’s a problem or the batteries run low.

Every second counts.

The Split­-Spectrum Sensor looks for both fast and slow-burning fires.

Hush from the Nest app.

Just burned the popcorn? Silence the false alarm with your phone, not your dish towel.

Tells you what and where.

Nest Protect speaks up if there’s smoke or carbon monoxide and tells you where it is, so you know what to do.

Expect more from your smoke alarm.

Easy installation.

Nest Protect takes only minutes to install and you can set it up from your phone.

Watch installation video  

Tech specs



Six long-life AA Energizer® Ultimate Lithium batteries


120V Connector

Three long-life AA Energizer® Ultimate Lithium backup batteries




  • Voice alarms with custom location
  • Phone alerts include:
    • Low-battery
    • Smoke
    • Carbon monoxide
    • Sensor failure
  • Split-Spectrum Sensor
  • Nest App
  • App Silence
  • Detects carbon monoxide
  • Heads-Up alerts
  • 10-year product lifetime
  • Sound Check
  • Nightly Promise
  • Self Test
  • Pathlight
  • Steam Check
  • Wireless Interconnect
  • Safety History
  • What To Do
  • Home Report
  • Emergency Shutoff with Nest Learning Thermostat
  • Emergency clip record with Nest Cam


Pre-installed languages by country

  • United States: English, Spanish
  • Canada: English, French (Québécois)
  • United Kingdom: English (British)
  • France, Belgium and Netherlands: French and Dutch

Note: After setup, you can change the language Nest Protect speaks to any of the above languages.


  • Split-Spectrum Sensor, 450nm and 880nm wavelength
  • 10 year electrochemical carbon monoxide sensor
  • Heat sensor, ± 1.8ºF (± 1ºC)
  • Humidity sensor, ± 3%RH
  • Occupancy sensor, 120º field of view to 20 feet
  • Ambient light sensor, 1-100k Lux Dynamic Range
  • Omnidirectional microphone, 70dBA SNR

Speaker, horn,
and light ring

  • 2 Watt Speaker
  • Horn: 85dB SPL at 10 feet (3 m)
  • RGB color ring with 6 LEDs

Size and Weight

  • Height: 5.3 inches (13.5 cm)
  • Width: 5.3 inches (13.5 cm)
  • Depth: 1.5 inches (3.85 cm)
  • Mass: 13.9 ounces (379 g)
  • Height: 5.3 inches (13.5 cm)
  • Width: 5.3 inches (13.5 cm)
  • Depth: 1.5 inches (3.85 cm)
  • Mass: 13.2 ounces (375 g)

Connectivity requirements

  • Wi-Fi connection
  • Phone or tablet with iOS 8 or later, or Android 4.1 or later
  • Free Nest Account


  • Working Wi-Fi connection: 802.11b/g/n @ 2.4GHz
  • Wireless Interconnect: 802.15.4 @ 2.4GHz
  • Bluetooth Low Energy (BLE)


Nest Protect has been tested to comply with safety standards in the United States set out by:

  • UL

  • California State Fire Marshal

Nest Protect complies with all of the following smoke and carbon monoxide alarm standards:

  • UL 2034 - “Single and Multi Station Carbon Monoxide Alarms”

  • UL 217 - “Single and Multi Station Smoke Alarms”

  • NFPA-72 - “National Fire Alarm and Signaling Code”

Operating Temperature

The alarm should not be installed in locations where the normal ambient temperature is below 40ºF (4ºC) or exceeds 100ºF (38ºC).
Humidity range: 20%RH to 80%RH (non condensing).


2-year limited warranty. For support, visit nest.com/support.

Our support team is also available by phone 24/7.

In the box

  • Nest Protect (Battery)
  • Six long-life batteries (Energizer® Ultimate Lithium "L91" AA)
  • Backplate
  • Four screws
  • User's Guide
  • Welcome Guide
  • 2-year limited hardware warranty
  • Nest Protect (Wired 120V)
  • Three long-life backup batteries (Energizer® Ultimate Lithium "L91" AA)
  • 120V AC connector
  • Three wire nuts
  • Backplate
  • Four screws
  • User's Guide
  • Welcome Guide
  • 2-year limited hardware warranty