In October of 2011 Nest Labs burst onto the digital home scene with the release of the Nest Learning Thermostat, a unique (albeit expensive) device that can create heating and cooling schedules based on your daily habits and can be managed from anywhere using your Wi-Fi network and a smartphone. The company's latest effort, the Nest Protect, follows in the footsteps of its ground-breaking sibling. The Protect is a combination smoke/carbon monoxide (CO) detector that uses a colored light ring and audible alerts to warn you of dangerous smoke and CO levels.

Among the Nest Protect's many features are an early warning system, a motion detector that lets you silence the alarm with a few waves of your hand, a self-check mechanism that tells you if the batteries are getting low or if the sensors have failed, and iOS, Android, and Web browser support. Like the Nest Learning Thermostat, the Protect is artfully designed and connects to your home's Wi-Fi, allowing you to keep a virtual eye on things while you're away. It has one other thing in common with the Learning Thermostat in that it carries a hefty price tag; at $129 (direct) it's significantly more expensive than what you'll pay for a typical smoke/CO alarm. While it's the first of its kind, it's such a good performer that it deserves our Editors' Choice award.

Features and Design

Available in white or black, the Protect eschews the usual round white casing used on 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 its stylish mesh cover are eight sensors, including heat, smoke, carbon monoxide, motion, ambient light, and humidity sensors. There's also a smoke chamber, six AA batteries, a speaker, an alarm horn, a Wi-Fi radio, and a wireless interconnect radio that allows each installed Protect to communicate with other installed Protect units. We reviewed the battery-operated Protect but there is a hard wired version available as well. Inside the neatly packed box are the detector, a mounting plate, four screws, a user guide, and a welcome guide. The AA batteries are already installed.

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. It glows blue during setup and while running 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. Nest refers to this as the Nightly Promise; the Protect is constantly monitoring its sensors and batteries to ensure that they are in good working order, which means you can retire to bed knowing that your alarms are at the ready.

I particularly liked the Pathlight feature; when you walk under the Protect when the lights are out the light ring glows with a soft white light to guide your way. This really comes in handy when venturing out into the kitchen for a glass of water in the middle of the night. If you prefer, Pathlight can be disabled using the app.

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 allows you to stand under the device and wave your hand at the alarm to silence it. It'll take four or five deliberate waves of the hand to do the trick, which is by design (Nest engineers wanted to make sure the alarm isn't silenced accidentally), but it is a very convenient feature nonetheless.

In addition to visual lighting effects the Protect uses a very 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 (called a Head's-Up) and when there's an actual emergency. If there's a Head's-Up alarm, the voice will say "Head's up, there's smoke (or carbon monoxide) in the kitchen (or whichever room is having an issue). The alarm may sound." If it's a false alarm caused by burnt toast, or you've located and quelled the source of the smoke or carbon monoxide, you can use the Nest Wave or reach up and touch the button to silence the alarm. If it's an emergency alert the light will pulse red, the siren will start beeping, and the voice will say "Emergency, there's smoke in the hallway" continuously. When one alarm gives an alert, every Protect alarm in the house will chime in, with each alarm identifying the room which triggered the event. Emergency alarms can be hushed with a wave or button press unless the alarm detects a critical level of smoke.

App Controls

The mobile app is very 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. If it's red you'll get a message with tips on how to proceed (such as to get out now, 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 such as Nest Wave, Pathlight, Head's Up, and Nightly Promise. 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 (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 getting low so you can replace them before they die.

Installation and Performance

As with just about every smoke/CO detector, the Protect is a snap to install. First, you have to download the app and create a Nest account. The app also controls the Nest Learning Thermostat and is available for iOS and Android devices. A Web browser app is available for PC and laptop users.

From the main menu choose Add Nest Protect and enter the six character Entry Key located on the back of the Protect. Next, pull out the paper tab that's installed for shipping purposes and press the Nest button. At this point you can choose between English or Spanish language modes. Next, look for the Protect on your device's list of available Wi-Fi signals, select it, and go back to the Nest app. Once the device is connected to the Protect (about 10-15 seconds) you are asked to name the alarm based on location (kitchen, hallway, bedroom, etc.) and choose whether to enable Pathlight or not. After another 10 seconds or so the Nest glows green and the voice informs you that it is connected to the Internet. You can now mount the Nest to your wall or ceiling using the mounting plate and screws, a job which shouldn't take more than 3-5 minutes.

There's no safe way to test a CO detector in the home, and I wasn't about to run a hose from my car's exhaust into the house, so I'll have to take the Underwriters Labs at their word when they say that the Protect complies with the UL 2034 standard for Single and Multi Station Carbon Monoxide alarms. However, Nest sent along a SmokeSaber Smoke Detector Tester, which as the name implies, lets you test the smoke alarm using fake (invisible) smoke.

Following the directions, I pressed the SmokeSaber's aerosol button for one second while it was positioned one foot from the alarm. Within a few seconds a melodic tone sounded and the Protect's light ring pulsed yellow, then pulsed red (my First Alert alarm, positioned next to the Nest, also began beeping). Once the light turned red the Nest's siren started beeping very loudly (three beeps per set). The voice alert, which was also quite loud, announced "Emergency, there's smoke in the hallway" continuously until the fake smoke dissipated, at which time it advised me to wave to silence the alarm. Before I had a chance to do so, the light ring went dark and the alarm went quiet. I repeated this test on the kitchen alarm with the same results. Both times the secondary alarm chimed in to alert me of the emergency, and both times I received messages in the app telling me when each alarm went off, the severity (yellow or red), and when it was quieted. The only thing missing here is 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.