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The Best Smart Smoke Alarm

By Roy Furchgott
Updated
A Google Nest Protect and a Kidde Hardwired Smoke Alarm with Indoor Air Quality Monitor, our picks for the best smart smoke alarms.
Photo: Marki WIlliams

If you buy only one smart device for your home, make it a smart smoke detector. The best ones don’t just warn you of possible fire or the presence of carbon monoxide—they also have a bevy of useful features that come from being internet-connected. They send you a smartphone alert in the case of an emergency, they alert you to a malfunction or low batteries (without chirping), and they are are easily silenced with an app (so you don’t have to hoist a broom).

We continue to recommend the Google Nest Protect as the best choice for most people. It sends speedy alerts of smoke or carbon monoxide to your phone. A voice warning precedes the siren, so you can stop it from sounding if you know it’s a false alarm (burnt toast again?). The Nest Protect constantly self-tests to ensure its sensors are accurate, and it has a motion-activated path light. Also, as smart devices go, it’s a good-looking device.

Everything we recommend

Our pick

Along with advanced fire detection, this model self-tests to ensure its sensors are working. It interconnects with other Nest Protects wirelessly, and it has an eye-pleasing design.

Runner-up

While this model lacks some of our top pick’s nicer features, it can link up with non-smart alarms to increase their IQ.

What to consider before buying


  • Alarm hush

    A smart smoke detector lets you silence false alarms with the app, if, say, you burn your bagel.

  • Check the lifespan

    Smoke alarms have a 10-year lifespan, based on the date of manufacture—not the sale. A new device will likely be several months old. If it is older, consider swapping it.

  • Smart automation

    Smart alarms can work with other smart devices, to turn on linked lighting or to shut down your HVAC to prevent smoke damage when triggered, for instance.

  • Check certifications

    Tested to UL standards means an alarm has passed the test once, but UL Certification means that quality-control testing is ongoing.

Our pick

Along with advanced fire detection, this model self-tests to ensure its sensors are working. It interconnects with other Nest Protects wirelessly, and it has an eye-pleasing design.

Compatible with: Amazon Alexa, Apple Home, Google Home

The Google Nest Protect has all of the features we recommend in a smart smoke alarm. It can detect both slow- and fast-burning fires, and it wirelessly interconnects with other Nest Protects. This model uses voice alerts to warn you which room the danger is in, and it gives you time to check before it triggers the siren.

Among all the models we’ve tested, the Nest Protect is the easiest to silence when an alarm is triggered—through the polished and friendly Nest app or by pressing the large button in the center of its face. This smoke alarm is also the only model that periodically self-tests to ensure all is functioning well; this cuts down on those annoying low-battery chirps in favor of useful smartphone notification. The Nest Protect is available in both hardwired and battery-powered versions, and so it should work in any home.

Runner-up

While this model lacks some of our top pick’s nicer features, it can link up with non-smart alarms to increase their IQ.

Compatible with: Amazon Alexa skills, Google Assistant

The Kidde Hardwired Smoke Alarm with Indoor Air Quality Monitor doesn’t have as many features as the Google Nest Protect, but it still works well, and it’s a much less expensive way to improve your smoke alarm system. In our testing, the Kidde alarm reliably sent alerts when it detected smoke or poor air quality, and the “hush” button let us manually shut down alarms set off by cooking. Unlike the Nest Protect, this alarm can be interconnected with budget-priced wired alarms, including ones from other brands. So if smoke is detected in any room, the Kidde alarm will also trigger and send you an alert (though you do lose some features that you would otherwise have when installing multiple smart devices, such as room-specific alerts).

Roy Furchgott has reviewed more than 1,000 tech products and over 500 apps, including a wide array of smart-home devices. His work has appeared in The New York Times, The Washington Post, Business Week, Forbes, and Wired. For this update to the guide, Roy seared an awful lot of tuna—in the interest of science, safety, and dinner.

The Google Nest Protect, our pick for best smart smoke detector, installed on a ceiling.
Photo: Michael Hession

A smoke and carbon monoxide detector is an essential safety device in any home. With smart models, the most valuable feature is that, unlike non-smart alarms, they send a smartphone alert if they’re triggered. An alarm doesn’t do much if no one is around to hear it, after all.

And smart models address many of standard detectors’ other more-irksome shortcomings, which prevent owners from using them properly. One is the temptation to disable an alarm because the low-battery alert is chirping at 2 a.m. Another is owners disabling them because they’re tired of false alarms from cooking.

Those are all real and meaningful problems people encounter with traditional smoke detectors. According to a 2021 report, almost three of every five home-fire deaths in the US resulted from fires in homes that either had no smoke alarms or had alarms that were disabled or non-functioning.

Smart alarms address these problems by warning you of low batteries well in advance. They self-test for reliability. And they alert you ahead of time when the alarm’s end of life is approaching.

Many smart alarms can also send word to a trusted contact, in case you miss the notification. Due to their ability to remotely contact you, smart alarms are especially great for owners of vacation properties and second homes. They’re also great in the homes of loved ones who need extra attention.

Three different models of smoke alarms.
Some of the models we have tested. Photo: Roy Furchgott

There are just a few smart smoke detectors to choose from. And because these are critical safety devices, we picked only the smoke detectors that have what we consider to be the most important smart features:

  • UL Solutions (previously Underwriters Laboratories) Certification
  • smartphone alerts sent when triggered
  • interconnection with other smoke alarms

We also looked for models with additional capabilities, such as:

  • carbon monoxide (CO) detection
  • easy installation
  • voice alerts, as well as a siren
  • location announcement during alarms
  • hush by app
  • low-battery, malfunction, and end-of-life alerts
  • integration with smart-home systems

Because the reliability of these devices can mean life or death, we considered only smoke alarms that meet UL standards for smoke and carbon monoxide (CO) detection. UL tests smoke alarms, smart or not, by the same standard, simulating both fast-burning and smoldering fires.

The units were tested in a roughly 1,500-square-foot, three-level rowhouse for more than a year.

We monitored smart alerts sent to an iPhone. In assessing each device’s companion app, we focused on ease of use, quality of installation guidance, how quickly notifications were sent, and the ease of silencing alarms.

We paid particular attention to the sensitivity of the sensors and how well they handled non-fire situations. Did the alarm make a distinction between cigar smoke, an extra-long fireplace match held beneath it, and cooking smoke? (Pro tip: Seared tuna reliably sets off alarms.) And in the case of real fire, did the detectors sound quickly and reliably and send a speedy alert to a phone?

A Google Nest Protect.
Photo: Marki Williams

Our pick

Along with advanced fire detection, this model self-tests to ensure its sensors are working. It interconnects with other Nest Protects wirelessly, and it has an eye-pleasing design.

Compatible with: Amazon Alexa, Apple Home, Google Home

The second-generation Google Nest Protect has been a top pick for years. And, due to its unmatched features and overall reliability, it continues to be: No other model we’ve tested comes close. It is rock-solid-reliable at quickly sending alerts about potential danger, via a combination of voice, siren, and smartphone alerts. And a particularly great feature is a voice alert that warns you before it triggers an alarm. So you can preemptively silence it in the case of false alarms (I’m looking at you, seared tuna).

Nest Protect alarms interconnect wirelessly. That means all of your Nest Protect devices are linked. So if one goes off, they all do—even if your house doesn’t have dedicated wiring for smoke alarms. Unlike our runner-up pick, however, the Nest Protect can’t be set up to connect with other brands. Therefore, to have a whole-home smart smoke alarm system, you’d need to install Nest Protect alarms throughout your home.

The Nest Protect is packed with sensors. Those include sensors for humidity (to reduce alarms from steamy showers and cooking), room occupancy, and ambient light (for the night-light), as well as carbon monoxide and smoke. Nest employs a Split-Spectrum Sensor, which the company claims is more accurate than photoelectric sensors, and it also produces fewer false alarms (from cooking or humidity). However, in our testing we saw no difference between the Nest Protect’s detection performance and that of competing models.

The Nest Protect automatically self-tests, and it warns you in the case of a device malfunction or low batteries. And that is all done via smartphone alerts—you never have to deal with those maddening chirps in the middle of the night. It also tests its speaker and alarm once a month, at a time you select (you can deactivate that feature). A status light on the alarm glows yellow if there is a problem. Press it, and the Nest Protect will say aloud what’s wrong (or you can look at the app).

A black and a white Google Nest Protect, shown side by side.
The Nest Protect is available as a battery-powered version, which requires the use of replaceable lithium batteries, and a hardwired version, which has a non-replaceable backup battery that lasts 10 years. Photo: Marki Williams

No smart detector was easier to install and control. We used the iOS app to scan a code on the Nest Protect, which paired it with our Nest account and assigned its location, “Living Room.” The app and the Nest Protect then performed a mutual test, and the detector was ready to go.

We love the Heads-Up warning. This alerts you with a chime and a voice announcement, saying, “Smoke is detected in the hallway, an alarm will sound soon, the alarm is loud.” It gives you a chance to stop the shrieking before it causes your cats to fluff up and scatter and your dogs start howling. Alarms are canceled with a press on the Nest Protect’s large surface button or through the app on your phone.

The Nest Protect’s path light illuminates when it senses motion, projecting a dim but useful light directly down. During an emergency, it will turn red to help you find a way to safety. It can be set to light when you walk past, which some may find annoying. This feature can be turned off to preserve power on the battery-only models.

The Nest Protect does enable smart-home automation—but only in the Nest ecosystem. For instance, if you have a Nest Cam, it will start recording video if an alarm sounds (even without a Nest Aware subscription). A Nest Thermostat will shut down the HVAC system to prevent smoke and fire from spreading, and it can turn on lights and unlock doors.

Flaws but not dealbreakers

The Nest Protect is extremely expensive compared with a standard smoke and CO alarm. To fully equip a two- or three-bedroom home, it would cost several hundred dollars for devices that require replacement in about 10 years.

The Nest Protect isn’t well integrated into the Google Home ecosystem; this is a common complaint and is a confounding aspect of using Nest devices. To set up and manage the Nest Protect, you must use the Nest app—not the Google Home app, as with other Nest devices.

There are frequent complaints that the Nest Protect devours batteries. We’ve read plenty of reviews in which device owners claim to have batteries drain in a matter of weeks (the hardwired model is immune). Looking into it, we believe many of those device owners likely used standard alkaline AA batteries, rather than the more expensive long-life lithium ones that Google Nest specifies. The battery-powered Nest Protect uses its batteries for the Pathlight feature, but you can set it to the lowest brightness to conserve battery power or disable the feature entirely.

Nest offers only a two-year limited warranty for the Protect. That’s compared with a 10-year limited warranty for the Kidde Hardwired Smoke Alarm with Indoor Air Quality Monitor.

Privacy snapshot

  • Nest collects information pertinent to the functioning of the thermostat; this may include IP address, location, age of home, and phone location. (You can opt out, following instructions found in the Responsive Advertising Practices section.)
  • Nest does not sell user data to third parties.
  • Some user data can be deleted here.
  • You can read the full privacy statement here.
A white Kidde Hardwired Smoke Alarm with Indoor Air Quality Monitor.
Photo: Marki Williams

Runner-up

While this model lacks some of our top pick’s nicer features, it can link up with non-smart alarms to increase their IQ.

Compatible with: Amazon Alexa skills, Google Assistant

The Kidde Hardwired Smoke Alarm with Indoor Air Quality Monitor has built-in sensors that detect humidity and temperature, as well as volatile organic compounds. It’s far less expensive than the Nest Protect, but it lacks some of our top pick’s compelling features (and it has some bugs to work out).

Kidde does a lot for less (though not everything). Because the Nest Protect is so pricey, installing a network of them for even a midsize house may be cost-prohibitive. This Kidde model provides a great, still-smart alternative: If you have hardwiring that interconnects your smoke alarms (as is required by electrical code in most locales), you can install this Kidde smart detector and then network it with bargain-priced, non-smart Kidde smoke detectors.

The result isn’t exactly the same as having multiple smart alarms; with the non-smart units, you don’t get individual spoken alerts about which room was triggered, or air-quality monitoring, or other smart features. Still, for the primary purpose of sending an alert when a fire is detected, this setup worked great in our testing (it even connects just fine with the very cheap hardwired Firex smoke alarms I previously installed).

The Kidde alarm has one main job, which it does well. In our smoke tests, the Kidde alarm called out “Fire!” as it should, and the “hush” button easily shut down cooking-activated false alarms. Alert notifications appeared on my iPhone quickly, and when I disconnected the Kidde to change its location, I got an alert that it was offline. Another nice feature of the app is the ability to have smoke alarm alerts go to other people on your contacts list, which you can customize.

Technically it supports Google Home and Alexa, but we had issues. There were flaws that Kidde is still working out—our unit was stamped with a QR code for a different model (according to support), which put a hitch in installation.

And though there is another Kidde smart smoke detector with fewer features (it doesn’t check air quality), they are nearly the same price, so we don’t recommend it.

Privacy snapshot

  • Kidde’s parent company, Carrier, says it collects personal information, but it’s not completely transparent about what that may be, other than location.
  • Personal information from the Kidde Mobile App may be sold to third parties, including insurance companies, data analytics companies, property management companies, and rental property booking sites. You may opt out.
  • The complete privacy policy can be found here.

First Alert has discontinued its entire line of smart smoke alarms. We had previously reviewed the First Alert Z-Wave Smoke & Carbon Monoxide Alarm.

The X-Sense XS-01 WS Wi-Fi Smoke Alarm doesn’t detect CO and isn’t UL-certified (the company says it meets UL standards). It is set up and managed using the Tuya smart app, but it isn’t compatible with third-party apps like Alexa, Apple Home, or Google Home.

This article was edited by Jon Chase and Grant Clauser.

Meet your guide

Roy Furchgott

Roy Furchgott has personally tried more than 1,000 pieces of consumer technology and more than 500 apps. Roy’s work has appeared in more than 100 publications, including The New York Times, The Washington Post, Business Week, Forbes, Outside, and Wired. In addition, Roy has won awards regionally and nationally for writing and regionally for photography.

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