Nest Protect

Nest Protect
Nest’s Protect follows in the footsteps of its groundbreaking Learning Thermostat. The Protect uses lights and audible alerts to warn you of dangerous smoke and carbon monoxide levels, and features an early warning system, a motion detector for easily silencing the alarm, a self- check mechanism, and iOS, Android, and Web browser support. Like the Learning Thermostat, the Protect is artfully designed and connects to your home’s Wi-Fi, letting you keep a virtual eye on things while you’re away. Despite its hefty price and being the first product of its kind, it’s such a good performer that it’s still deserving of our Editors’ Choice award.


Available in white or black, the Protect eschews the round white casing typical of most home smoke detectors. Instead, it uses a square 5.28-by-5.28-inch housing that is 1.63 inches thick and weighs 13.1 ounces. Behind the stylish mesh cover are eight sensors, for gauging heat, smoke, carbon monoxide (CO), motion, ambient light, humidity, and more. There’s also a smoke chamber, six AA batteries (which come preinstalled), a speaker, an alarm horn, a Wi-Fi radio, and a wireless interconnect radio that lets multiple installed Protect units communicate with each other.

(We reviewed the battery-operated Protect, but a hard- wired version is also available.) Also included are a mounting plate, four screws, a user guide, and a welcome guide. In the center of the alarm is a 2.25-inch round “Nest” button surrounded by a light ring that glows different colors to display the unit’s current status: blue during setup and tests, yellow when giving a Head’s Up (early warning), and red when there’s a smoke or CO emergency. Otherwise it remains unlit. When you turn out the lights at night the ring briefly glows green to let you know that everything is working correctly; walk under the Protect when the lights are out and the light ring glows soft white to guide your way.
If you’ve ever had to get up on a chair so you could reach your smoke alarm’s quiet button you’ll appreciate the Nest Wave feature, which lets you stand under the device and wave your hand at it four or five times to silence it. (Nest engineers wanted to make sure that it wasn’t possible to silence the alarm accidentally.) In addition to visual lighting effects the Protect uses a loud beeping alarm and a female voice to broadcast alerts. The voice will tell you when there’s a potential for dangerous smoke or CO levels and when there’s an actual emergency. If there’s a Head’s Up alarm, the voice will tell you where the smoke or CO is, and that the alarm may sound. If it’s an emergency alert the light will pulse red, the siren will start beeping, and the voice will sound continuously. When one alarm gives an alert, every Protect alarm you have installed in your house will chime in, with each identifying the room that triggered the event. False and emergency alarms alike can be hushed with a wave or button press unless a critical level of smoke is detected.

The mobile app is basic, but well designed and user friendly. The main page shows each alarm and its status. If all is well you’ll see a green circle, if there’s a Head’s Up warning it’ll be yellow, and if there’s an emergency it’ll be red and you’ll receive a message with tips on how to proceed (such as warnings to get out immediately, feel the door before opening it, alert all children, and call 911).
Clicking on an alarm shows you when it was last updated and manually tested, and if the batteries are good. The settings menu lets you change the name and location of each alarm and enable or disable features. When an alarm is triggered a message is sent to your app mailbox stating which alarm went off and the event level.
As is the case with most smoke/CO detectors the Protect has a life expectancy of seven years. Two weeks prior to the expiration date (which is printed on the back of the device), the alarm will warn you that it has expired and needs to be replaced.
It will also warn you when the batteries are running low.


As with just about every smoke/CO detector, the Protect is a snap to install. First, you need the app (it also controls the Learning Thermostat), which is available for iOS or Android, or over the Web, and to create a Nest account. You add the Protect to the software, enter the six-character entry key on the back of the device, pull out the paper tab that’s installed for shipping purposes, and press the Nest button. Then you choose a language (English or Spanish), link the Protect to your Wi-Fi network, name the device, and it’s ready to mount.
There’s no safe way to test a CO detector in the home, so I’ll have to take the Underwriters Labs at their word for their claims that the Protect complies with the UL 2034 standard for Single and Multi Station Carbon Monoxide alarms. But Nest sent along a SmokeSaber Smoke Detector Tester, which as the name implies, lets you test the smoke alarm using fake (invisible) smoke.

When I used it, the Protect’s light glowed red and its siren and voice alerts sounded until the fake smoke dissipated; the alarm then silenced itself before I could do so manually. I received the proper alert messages in the app, too. The only thing missing here are email and text-message alerts, which would add another layer of event reporting for when you’re away from home. Right now you have to open the app to receive messages.


The Nest Protect takes smoke and carbon monoxide detection to a whole new level. It doesn’t just alert you to dangerous smoke and CO levels with a series of piercing beeps, it warns you of developing situations so you can take action before things get out of hand. Color- coded lights, articulate voice alerts, and the Nest Wave all make the Nest Protect a top choice. Sure, there are plenty of good smoke/CO detectors out there for a fraction of the cost, but none of them offer all of the safety and monitoring features that you get with the Nest Protect.

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