Nest Protect – Smoke Alarm – Smoke Detector and Carbon Monoxide Detector review


Which is better – Nest Protect wired vs battery? When a smoke or carbon monoxide detector is triggered, the Nest Protect will flash its built-in light, sound an alarm, and use voice alerts to let you know exactly what type of emergency it’s detecting. It also sends alerts to your phone through the app. Get details in Nest Protect – Smoke Alarm – Smoke Detector and Carbon Monoxide Detector review.

We independently review everything we recommend. When you buy through our links, we may earn a commission. Lean how we earn commission

In the box

  • Nest Protect: 2nd Gen Smoke + CO Alarm
  • Backplate
  • Four screws
  • 120V AC connector (Wired model)
  • Three wire nuts (Wired model)
  • Six long-life AA batteries (Battery model)
  • Three long-life backup AA batteries (Wired model)
  • User’s guide
  • Welcome guide

Pros & Cons


  • Mobile alerts
  • Voice alerts
  • In-app battery warnings
  • Carbon monoxide alarm
  • Light


  • Expensive


  • Color: White
  • Dimensions & Weight : 5.3 in L • 5.3 in H
  • Wireless: 802.11b/g/n (2.4GHz) Wi-Fi
  • Sensors: Split‑Spectrum smoke sensor
  • Battery: Six long-life AA batteries
  • Audio: 80 dB @ 3 ft (1 m) @ 1kHz
  • Operating Temperature: 40ºF (4 ºC) to 100ºF (38 ºC)
  • Horn: 85 dB SPL @ 10 ft (3 m)
  • Certification: Complies with safety standards set out by UL
  • Warranty: Two-year limited warranty
  • External Buttons: RGB color ring with 6 LEDs


At $100, the Nest Protect is one of the most expensive, but also one of the most comprehensive, of the smart smoke detectors we’ve tested. Not only does it pick up several types of fires, as well as carbon monoxide, but it also does the best job at alerting you of the danger.

What is good in Nest Protect – Smoke Alarm – Smoke Detector and Carbon Monoxide Detector?

  • Differentiates between steam and smoke
  • Automatically sends alerts to your phone
  • Split-spectrum smoke sensor
  • Can be silenced from phone 
  • Detects both fast and slow-burning fires
  • Lights up a path when walking underneath it
  • Smoke and carbon monoxide detector has a 10 year lifespan
  • Detects carbon monoxide
  • Self-testing
  • Speaks to tell you what the problem is
  • Emergency shut off

Nest Protect – Smoke Alarm – Smoke Detector and Carbon Monoxide Detector review


The Nest Protect comes in both wired and battery-powered versions. If you have more than one in your home, and one goes off, the others will too, alerting you to the location of the fire.. 5.3 x 1.5 x 5.3 inches, ‎1 pounds. An LED ring on the bottom of the alarm also changes color, giving you a visual cue.


The Nest Protect uses a split-spectrum sensor that Nest says is good at detecting both slow-smoldering fires as well as fast-burning ones. It’s a photoelectric sensor, which is generally better at sensing smoldering fires (ionization sensors are faster at quick-burning fires, but are more prone to nuisance alarms), but Nest’s sensor has a second wavelength that’s better for picking up flaming fires. In addition, the Nest Protect has sensors for carbon monoxide, heat, humidity and occupancy.

Phone alerts

Yes, a siren is very helpful in alerting you to a fire, but doesn’t provide any information other than that. Nest Protect is different in that it also provides spoken alerts, which not only tell you the nature of the emergency (smoke or carbon monoxide), but also the room in which it’s occurring.

Apps feature in Nest Protect – Smoke Alarm – Smoke Detector and Carbon Monoxide Detector

On top of keeping your family safe, it comes with a few aggravation-saving features. Its app will tell you when the battery is low so you don’t need to listen to a constant beeping noise until you change the battery. You can also turn off false alarms with the app. No more using a broom handle to tap the button.

Nest Protect can connect with other Nest Protect alarms in your home to create a network of safety. This means voice alerts could tell you where smoke or fire was detected. This can keep you safe as you exit your home because you’ll know which rooms to avoid.

Through the Nest app, you can monitor the status of the detector, as well as any other Nest products you have, such as the Nest Cam and the Nest Learning Thermostat. The app gives detailed information on when the Nest Protect last checked itself, and if there are any issues. From here, you can also silence the alarm if it goes off accidentally while you’re cooking a steak, for example.


To install the Nest Protect, you first screw a base plate into the ceiling, and then attach the main body of the smoke detector onto the base plate. Then, you connect to it using the Nest app on your smartphone (Android and iOS), specifying, among other things, in which room the Nest Protect is located. It’s a fairly simple process that took me about 5-10 minutes.

Smart Home Integration

You can link the Nest Protect to other smart-home systems, such as Google Home (and the Mini and Max), TP-Link smart plugs and Philips Hue lights.

However, this only applies if you still have the Protect registered under a Nest user account, and not a Google Assistant account. Last year, Google started the process of merging Nest with Google Home/Assistant, but almost all of the functionality available within Nest has not been enabled within Google.


We tested the Nest Protect (as with all smoke detectors) by spraying an aerosol smoke-detector-tester spray from 5, 10 and 15 feet away, and timing how long it took each alarm to go off. At the 5- and 10-foot mark, the Nest Protect sounded after 18 seconds. At 15 feet, the alarm activated after 28 seconds. Moreover, it was the only device to pass all of our tests.

Nest Protect – Smoke Alarm – Smoke Detector and Carbon Monoxide Detector customer review

Preeminent Protection for Your Loved Ones

Nest Protect Smart Smoke/Carbon Monoxide Alarm provides the ultimate protection & peace of mind. The intelligent alerts discriminate between steam and smoke. A clear “Heads Up!” pre-alert gently cautions you in situations when close proximity to steam or a little smoke in the kitchen, for example, is about to trigger an alert. You can silence a false alarm using your phone. Multiple units share alerts to all rooms & to your NEST App on your phone, tablet & computer – so you are protected throughout your home! The “Promise” is a ring of green light that illuminates nightly to let you know everything is good.

Walk under NEST at night & the ring glows white, forming a pathlight. During Heads Up, it glows yellow. During an emergency, it glows red. NEST Protect self-tests, alerting you first by the phone app that it will sound. Everything is tested: sensors / voice / siren. Tests are dated & are sent to your app. A monthly summary even shows the exact date & time of each test. This is the premiere smoke detector, able to detect CO2 (even produces a completely different sound, for instant identification).

NEST Protect senses both fast and slow burning fires. NO CHIRPS!! This advanced Smoke Alarm eliminates all of the hassles of pesky chirps from low batteries, with super long lasting Lithium Batteries included that last years. Battery alerts are through your App & by voice on the Alarm. To set-up, simply scan the QR Code on the back of the NEST & follow the voice instructions. Easiest set-up ever! NEST Protect earns my highest recommendation – no other Smoke / CO2 Alarm even comes close!

By gadgetguy11 at Best Buy

Alternate of Nest Protect – Smoke Alarm – Smoke Detector and Carbon Monoxide Detector

First Alert SA320CN: Best basic

The First Alert SA320CN is fairly basic compared to our top pick. It’s reliable, though, and that’s the most important thing when it comes to fire detection. Plus, First Alert has been around since 1958 and is highly trusted.

The 85-decibel siren could be louder, but we think it should do just fine if you place multiple alarms throughout your home. It can detect both fire and smoldering using its dual sensors, and it has a testing button that can also be used to mute the alarm.

It’s not the flashiest, but we think it’s a great pick if you need a budget-friendly, no-fuss smoke detector

Editor’s recommendations

Lead Content Editor
Lead Content Editor

I enjoy creating stuff and giving back to my community. My days are spent producing content for brands who need an internet presence and for things that I adore. I bring with me six years of experience generating content and obtaining leads from untapped markets. I concentrate on the qualities and advantages of the goods that add value for my audience. After reading my reviews, anyone who want to purchase a product from me are given my honest and open recommendation. I integrate my reviews with those of actual people to make the content authentic and accurate. Please take a moment to contact me if you see any deviations; I always value and appreciate hearing from my readers.

Articles: 1412