Nest Protect CO/Smoke Alarm


The smoke alarm other alarms look up to. It thinks, before it speaks. Nest Protect has a friendly human voice that gives you an early warning. That way you can handle burning toast before it becomes a burning toaster. Tells you where the danger is. It’s on your ceiling. And on your phone.


  • 10-year CO sensor.

Carbon monoxide is poisonous but you can’t see it or smell it. That’s why Nest Protect has the most accurate type of carbon monoxide sensor available. We also improved our carbon monoxide sensing algorithm. And we’ll keep working to make it better and better because people depend on it.

  • Tests itself

You’re supposed to test smoke alarms monthly. But 9 out of 10 people don’t. So Nest Protect checks its batteries and sensors over 400 times a day. And it’s the first alarm that uses Sound Check to quietly test its speaker and horn once a month.

  • Lights your way

If you need a glass of milk in the middle of the night, Nest Protect lights up as you walk underneath it. Pathlight is one of our customers’ favorite features so we made it better and brighter.

  • Steam is not smoke

Has your alarm ever yelled at you for taking a shower? Nest Protect is the only alarm with Steam Check. It uses custom algorithms and a humidity sensor to look for steam, so you can enjoy a nice, quiet shower.

Look for the light ring.

In addition to its voice, Nest Protect uses colors to communicate. And we gave the new Nest Protect a brighter light ring so it’s easier to see in an emergency and better at helping you see things in the dark.

  • Nightly Promise

Nest Protect constantly monitors its sensors and batteries. A quick green glow when you turn out the lights says everything’s working.

  • Pathlight

When you walk under Nest Protect at night, it will light your way. You can choose different light levels or turn Pathlight off entirely in the app.

  • Heads-Up

If there’s only a little smoke, like you’ve just burned toast, it will glow yellow and give you a friendly Heads-Up so you can check on things.

  • Emergency

When smoke or carbon monoxide reaches dangerous levels, Nest Protect sounds the alarm, pulses red, and tells you where the emergency is.


Technical Specs



  • Length: 5.3 in (13.4 cm)
  • Width: 1.6 in (3.95 cm)
  • Height: 5.3 in (13.4 cm)


  • Nest Protect Battery: 13.9 oz (379.0 g)
  • Nest Protect Wired: 13.2 oz (375.0 g)


  • White


  • Split‑Spectrum smoke sensor
  • 10 year electrochemical carbon monoxide sensor
  • Temperature
  • Humidity
  • Occupancy (120° field of view up to 20 feet)
  • Ambient light
  • Accelerometer
  • Microphone


  • Battery model: Six long-life AA batteries (Energizer® Ultimate Lithium “L91”)
  • Wired model: Three long-life backup AA batteries (Energizer® Ultimate Lithium “L91”)


  • 802.11b/g/n (2.4GHz) Wi-Fi
  • 802.15.4 (2.4GHz)


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


  • Speaker loudness: 80 dB @ 3 ft (1 m) @ 1kHz


  • 85 dB SPL @ 10 ft (3 m)


  • Two-year limited warranty.


  • Nest Protect has been tested to comply with safety standards UL 2034, UL 217, and NFPA-72 set out by UL and California State Fire Marshal.


  • RGB color ring with 6 LEDs