It’s hard to overstate the importance of having functioning, reliable smoke detectors in your home. From 2007 through 2011, almost a quarter of all home fire-related deaths in the US occurred in homes with nonworking smoke alarms. While any functioning smoke alarm will alert you to problems if you’re at home, a smart alarm can alert you anywhere your smartphone has an Internet connection. For our tests, a former firefighter installed every currently available smart smoke alarm in her own home, both hardwired versions and battery-powered models, to find the best one for keeping you informed about your house’s status, whether you’re home or away. After mounting them to ceilings and walls, blowing smoke at them, fiddling with their batteries and accompanying apps, and generally pushing their buttons, we found that the second-generation Nest Protect smoke and carbon monoxide alarm is the best smart smoke alarm.
A sleek design, sensitivity to slow- and fast-burning fires, self-testing, and straightforward apps make Nest’s Protect a great smart fire-safety device.
The Protect is significantly more expensive than some other smart-alarm options, but we think it’s worth the premium because it does the most to keep your household informed and safe with its full set of safety features, its intuitive app, and voice alerts that tell you where the alarm is sounding and what the problem is. While all the smart alarms we tested will send an alert to your phone if they go off, the Protect goes above and beyond with features that no other alarm can match as of yet. Other smart smoke detectors can self-test their battery levels, but the Protect also tests its sensors, so you know for sure it’s working correctly. That means you’re less likely to disable your alarm out of frustration due to an excess of false alerts. We also like that multiple Protect alarms will interconnect wirelessly and go off simultaneously if just one detects smoke—like standard hardwired alarms and some battery-powered alarms. The Protect is the only smart alarm that comes in hardwired and battery-powered versions and works with both iOS and Android, making it compatible with every home.
We believe that smart smoke alarms should appeal to people who wouldn’t otherwise be interested in smart-home technology. For anyone who is already invested in a smart-home setup, however, the Protect, as part of the Nest ecosystem, also offers handy, safety-oriented integrations like the ability to flash your smart bulbs to alert you and light your way when the alarm goes off, plus the ability to shut off your HVAC unit in an emergency (a crucial step, according to firefighters we spoke with). Other smart alarms have some of those capabilities, but the Protect is the only model that offers all of them in one package.
If the only feature you care about is the ability to receive notifications when your smoke alarm goes off while you’re not at home, the Wi-Fi–enabled Roost Smart Battery can do that on the cheap. For less than $35 at this writing, you get a 9-volt battery that installs into your existing smoke detectors (wired or battery-powered) and should last five years. Like the Nest Protect, the Roost Smart Battery sends an alert to your phone telling you where the alarm is going off and giving you the option to silence it. In addition, Roost will automatically notify someone else about the alarm in your home when it’s triggered, without giving that person control over all your other smart-home devices (as is the case with Nest’s version of this feature). But unlike the Protect, the Smart Battery doesn’t give you voice alerts, wireless interconnectivity, integrations with smart-home devices, or self-testing sensors—although it does self-test its battery level silently and notify you that it’s still working. Because of those omissions in the Smart Battery, we think the Nest Protect is better for most people despite its higher price tag. But many of those features, while useful in a larger home, might not be necessary for a smaller apartment or cottage that could get sufficient coverage from just one or two smoke detectors.
Why you should trust us
To compile this guide, we read multiple research papers, spoke to engineering experts at UL (formerly Underwriters Laboratories), and scoured numerous customer reviews of the devices we tested. A journalist for close to 20 years, I have been writing about smart homes and the Internet of Things since 2012; I also have six years of experience as a firefighter and an emergency medical technician.
Who this is for
Among all the smart-home devices available today, a smart smoke alarm is probably the most important and the one that even smart-home skeptics should consider. The primary task of any smoke alarm, smart or not, is alerting you to potential danger. A smart alarm will do so even when you’re not home, and for most people, that should make such an alarm worth the price. Whether you’re across the street or across the country, a smart alarm will let you know (via your smartphone) when it detects smoke in your home.
Another benefit of smart smoke alarms over standard ones is that you can more easily tell when they’re not working. Manufacturers and fire-safety experts say you should manually test your alarms once a month and replace the batteries twice a year (at the same time you change your clocks). Smoke alarms are either battery-powered or hardwired (meaning you can install that kind only where the house has wiring to support it), but even hardwired alarms have batteries in them in case the power goes out. Smart alarms can periodically test themselves or allow you to test them remotely through their companion app, and some have batteries that last five to 10 years, helping to make sure you have working alarms in your home.
One of the biggest problems with regular smoke alarms is that too often they stop working, either because a sensor died or because the device lost a fight with a broom handle when you couldn’t reach the silence button. Some smart alarms also let you silence “nuisance” alarms through the app on your phone (rather than pulling the battery out), meaning you’re a lot less likely to end up with a nonworking alarm in your home. It bears repeating: According to a 2014 report, almost a quarter of all home-fire-related deaths in the United States from 2007 through 2011 occurred in homes with nonfunctioning smoke alarms.
If you already need to replace your smoke alarms anyway—fire-safety experts recommend doing so every 10 years because sensors wear out—we think the price premium for going smart, while not insignificant, is a small one to pay for added peace of mind. This is especially true if you already have other smart-home equipment such as cameras, which allow you to confirm whether something has actually gone awry in your home when an alarm goes off.
But what if you have a house full of perfectly functional alarms? Whether it’s worthwhile to replace your functional dumb smoke detectors with smart ones depends on how much you value knowing whether an alarm is going off while you’re not at home. If $100 for a single Nest Protect is too much to swallow, a Roost Smart Battery can get the job done for about a third of the cost and installs right into your existing smoke detector. Or maybe you’re not worried about the state of your home when you’re not present, and that’s fine too.
Even so, there is one situation where we recommend seriously considering replacing a house full of functioning smoke detectors. If you have more than four rooms and a house that is not wired for interconnected smoke detectors—so that they all sound off if one gets tripped—we think the Nest Protect is an easy upgrade for the safety of your home. At $100 a pop, the costs add up quickly, but interconnectivity is a safety feature that most building codes have required for more than a decade by now, because it’s just plain sensible. You can get that feature with some battery-powered non-smart alarms, but the Nest Protect offers interconnectivity with smartphone alerts.
How we picked
We looked at both battery-powered and hardwired alarms, and we evaluated their wireless interconnectivity features.
A smart smoke alarm should alert you on your smartphone when it senses smoke, as well as tell you which room is in danger; it should also include intelligent low-battery alerts and remain easy to silence safely from the app. Some other features worth having include voice alerts, self-testing and reporting, and the ability to reach an emergency-contact person automatically if you don’t respond.
Most important, an alarm should connect wirelessly with other alarms in the home, or come in a hardwired version that you can wire to other alarms, so that when one alarm senses danger all alarms in the house will sound. This is a crucial safety feature that can save you precious seconds in evacuating your home. Also, many states now require interconnected alarms for new construction, so if you do a significant remodel in your home, you don’t want to end up having to buy a different brand of alarm for the new area (most brands don’t play well with one another when it comes to interconnected alerts).
Although this review primarily focuses on the smart-home features of smoke alarms, it’s of course important that they do their primary job well, and that is to detect potentially life-threatening situations in your home. Because your safety is at stake, for us to even consider a smoke alarm for testing, it had to meet UL standards for smoke and carbon monoxide (CO) detection. UL (formerly Underwriters Laboratories) is a safety consulting and certification company that has been keeping Americans safe for more than 100 years by drafting standards for the electrical devices and components people use every day. UL tests all smoke alarms, smart or not, by the same standard, simulating both fast-burning and smoldering fires, so you can feel confident that certified technology will keep you safe, whether the alarm uses photoelectric sensors, ionization sensors, or a proprietary method involving a combination of sensors. All the alarms we tested are UL Listed, apart from the First Alert brands, which are tested to UL standards by ETL (which is also a Nationally Recognized Testing Laboratory).
Smoke alarms available today use either ionization or photoelectric sensing. In the fire-safety industry, there is an ongoing debate as to the best use of such sensors to protect people’s homes. Ionization sensors respond slightly quicker to fast-burning fires, while photoelectric sensors are faster at detecting smoldering fires (the more common type in homes). In a properly tested alarm, either sensor should respond to each type of fire within the recommended time.
Ionization alarms, however, are prone to nuisance alarms, making them more likely to be disabled by the home’s residents and leaving that house at greater risk. Ionization alarms have even been banned in some places because of this problem, and they are not recommended for use in kitchens or near bathrooms due to a higher likelihood of false alarms in these areas. Consequently, some authorities advocate for the installation of both types of alarms, others for dual-sensor units that detect both kinds of fires, and others for photoelectric alarms only. The policies vary from state to state. No one recommends ionization alarms only.
“While the National Fire Protection Association suggests having both ionization and photoelectric alarms in your home is the optimum situation, our present requirements cover both and will give you adequate warning to get out,” John P. Drengenberg, consumer safety director of UL, told us. “The standard is based on tests that we do to smoke alarms—irrespective of ionization or photoelectric, they both have to pass all of those tests.”
In the end, we wound up testing seven smart fire alarms and similar devices that included options that met our requirements.
How we tested
To test these devices, we put them in a two-story, detached home. We installed both battery-operated and hardwired versions (where available) and used their self-testing features to evaluate the effectiveness of their smart alerts and wireless interconnectivity capabilities. Additionally, we simulated smoke with each device to determine how well the alert features worked in a “real-life” scenario.
We evaluated each device’s companion app, looking at how well and how quickly it sent the notification of danger (if your smoke alarm is doing its job, you really won’t need to spend much time in the app beyond setup). We also connected the devices to any smart-home systems they were compatible with and evaluated the effectiveness and usefulness of any added features.
All the devices we tested responded appropriately to the presence of smoke, and none gave any false alerts during the month they were installed in our test house. Because our test home is not a certified laboratory, we focused our reviews on the ease of installation and use, as well as on the “smarts” each device offered.
The second-generation Nest Protect smoke and carbon monoxide alarm is the best smart smoke alarm for everyone because it reliably and calmly alerts you to potential danger whether you’re home or away, before the actually loud and grating alarm kicks in. It also informs you of problems such as a device malfunction or low batteries without waking you up at 2 a.m. It lets you silence nuisance alarms through its app—so you’re less likely to disable it in a fit of annoyance. On top of that, it interconnects with other Protects to sound the alarm throughout your home, and it integrates with your smart-home system to further mitigate the dangers of a fire or carbon monoxide event.
The Protect’s sensors can detect carbon monoxide, heat, humidity, room occupancy, and ambient light. It also has the Split-Spectrum Sensor, a sensor unique to Nest that, while photoelectric, promises to detect fast-burning fires more quickly than traditional photoelectric sensors do. It accomplishes this with a second LED that may be able to pick up the finer particles of fast-burning fires. This means that while it offers performance similar to that of an ionization alarm, it is less likely to suffer from nuisance alarms.
Perhaps most important, the Protect self-tests its functions every 200 seconds, in addition to performing a sound check once a month to test its speaker and horn. Colored status lights (green for good, yellow for problems) let you know the Protect is working properly. While a couple of the other smart alarms we tested conduct self-checks, none of them do so in a way that’s so visible to the user. For example, the First Alert Onelink battery-powered alarm is completely dark at all times unless there’s an emergency, a design that often led us to wonder whether it was working at all. In contrast, if your Nest Protect is glowing yellow, it will announce what’s wrong, or you can look at the app to see what the issue is. That type of peace of mind is worth a lot in our opinion.
When the Protect is triggered, the alert takes you to the app, where you can silence the alarm. If smoke or CO levels are too high, it will tell you that it can’t silence the alarm and will give you guidance on what to do next.
The Protect’s home-automation capabilities are what make this model truly smart, and the winner among smart smoke alarms. Chief among those features is compatibility with the Nest Cam, which will start recording video if an alarm sounds (you need a Nest Aware subscription), and the Nest Learning Thermostat, which will shut down the HVAC system to mitigate the spread of the fire. An HVAC unit can be the cause of smoke or fire events in a home, and shutting it off is often one of the first things a fire crew does when arriving at your house. Additionally, if you have a Nest thermostat, your Protect alarms can act as motion or occupancy detectors to feed data to your thermostat about whether you are home or not.
The Protect integrates with other connected devices through the Works with Nest program. In our testing we linked it to Philips Hue colored light bulbs, and they flashed red when the alarm activated. Among other integrations, the SkyBell HD video doorbell will turn red if the Protect senses smoke or carbon monoxide inside, the Rachio smart sprinkler controller will cycle your sprinklers if the Protect senses an emergency, and Lutron smart shades will open in the event a fire is detected so that emergency responders can see inside the home.
Nest also offers an extensive IFTTT channel, so you can set up additional alerts and other smart-home customizations. But a lot of the functionality that the IFTTT recipes offer is already available in the native app or through the app of a Works with Nest partner. Due to the lag time you may experience while using a third-party, cloud-based option like IFTTT—which also won’t work if the Wi-Fi is down in your home—we recommend enabling features via the native app or a Works with Nest partner app first and using IFTTT only if you can’t find a suitable option for what you want to do.
The Protect’s Pathlight illuminates as you walk under it at night, and it will shine red when there’s an emergency, helping you see your way out. The Heads Up warning speaks to you before the alarm’s loud sirens start sounding, and Family Accounts let everyone in the household receive alerts on their devices if something is wrong. The Protect is also nicely styled, and it’s the only smart smoke alarm we tested that comes in both black and white, for easier coordination with a variety of decor.
Installing the Nest Protect is straightforward. We had two units, a battery-powered version and a hardwired version. We used the app (which is available for iOS and Android) to scan each device to pair it with our Nest account, after which we told the app which room each Protect would be in. The app and the Protect alarms then did a mutual test, and once that was complete they were ready to go on the ceiling (or wall, your preference).
The advantage of a battery-powered alarm is that you can place it anywhere in your home. Mounting the Protect is straightforward: Pop in the six included lithium AA batteries (which are designed to last five years), screw the mounting plate to the ceiling or wall (you can install it wherever you like), and twist the Protect into place. All the battery-powered alarms we tested had similarly easy installs, but the Protect was the only one that didn’t require us to drill holes in the ceiling or wall, as it comes with mounting screws that go directly into drywall and don’t need anchors.
The Nest Protect installs easily and comes with mounting screws that don’t require drywall anchors.
For the hardwired version, installation is slightly more complicated because you have to turn off power at the breaker, and you can put the Protect only where your home has the correct wires to support it (as with any hardwired alarm). We had to remove our test house’s already installed old alarm (saving the screws from the backplate), in addition to removing the old connectors by unscrewing the wire nuts, replacing with the Protect wires, and then screwing the caps back on. If you have an interconnect wire (red/orange/yellow), it isn’t necessary, since Nest uses its own wireless mesh network to connect Protect alarms; we just capped it and tucked it away.
Next we installed the Nest backplate by screwing it into the existing electrical box, using the original screws (it can also screw directly into a ceiling or wall with the Nest-supplied screws). Finally, we plugged the 120-volt connector into the back of the Protect and twisted the device onto the backplate until it clicked. Once it was in place, we were able to rotate it as needed (up to 360 degrees) to line up with the wall.
Flaws but not dealbreakers
These alarms are very expensive. To fully outfit a standard two- or three-bedroom home, you’re looking at an investment of around $800. Factor in a manufacturer-set life of 10 years, and that’s an outlay of $2,400 over 30 years in a home. When you’re considering the price, the choice comes down to how much you value functions such as the ability to learn, from wherever you are, that your home is in danger, as well as interconnectivity for alerting the whole household to the danger—you have to decide whether those functions are worth the extra $60 per unit (or more than $1,400 over those 30 years). You also need to factor in the Nest Protect’s additional features, such as self-testing, avoidance of low-battery chirps, and smart-home integrations that can add to your safety, as well as its attractive design.
When the Protect debuted in 2013, it saw a slew of owner complaints about false alarms that couldn’t be silenced (UL standards require that certain types of alarms prevent silencing to discourage people from ignoring a dangerous situation). These were false alarms—that is, instances when the alarm went off for no obvious reason—as opposed to nuisance alarms, the kind that sound when burnt toast sets them off. Nest recalled the first-generation Protect in 2014, primarily due to an issue with a wave-to-silence feature that the company has since disabled. After the launch of this redesigned second-gen model, complaints about false alarms subsided but did not completely disappear.
Nest told us that its research into such complaints revealed that the majority of people encountering this issue were using first-generation Protect models. Second-generation models that produce false alarms are most likely affected by a buildup of dust, the company’s representative said, which can clog the sensors. If you experience this problem, Nest’s recommendation is to wipe the device regularly with a clean, dry cloth.
Nest offers only a two-year limited warranty for the Protect, in contrast to seven to 10 years for all the other smart alarms we tested.
The battery-powered Protect uses six AA lithium batteries, and how long those will last depends on how much use the device gets. Some owners have complained about their alarms chewing through batteries in a matter of weeks. Nest’s response is that “75% of low battery reports we’ve investigated occurred when people replaced them with standard AA batteries, rather than purchasing the lithium ones recommended.” The battery-powered Protect uses its batteries regularly for the Pathlight feature, and if your device is in a little-used room, the batteries will probably last the suggested five years. But if you have it in a hallway, the frequent activation will drain the batteries more quickly. Nest recommends disabling Pathlight or setting it to the lowest brightness level if battery drain is a problem.
Although you can add an emergency contact to your Nest account and be prompted to call that number when your alarm goes off, currently the Protect won’t automatically notify someone else if you don’t respond to its notification. A very useful emergency feature would be the ability to have the app send a text message or call a predesignated emergency contact if you don’t respond. Both the Roost battery and the Leeo smart alerter offer this function.
Who else likes our pick
CNET’s Megan Wollerton agrees that Nest’s Protect is the best smart smoke alarm available, writing, “No other smoke and carbon monoxide detectors available today can match [it] in terms of looks and options.”
Engadget reviewer Roberto Baldwin calls it a solid investment for anyone who wants to constantly monitor their home, and points out that “it’s a safer solution than what you have on your ceiling right now.”
Despite encountering some issues in his testing, Ars Technica reviewer Nate Anderson was pleased with his Protect alarms. “[T]hey do appear to offer significant improvements in smoke detection over many competing units. The glowing colored lights and calm voice are infinitely preferable to shrieking dumb units, and the interconnected nature of the devices adds to their safety,” he writes.
Roost’s smart functions come as a battery that you install in any smoke alarm, or as a complete alarm with the battery already installed.
If notifications when you are away from home are your main priority, a Roost Smart Battery is an excellent, inexpensive choice. This 9-volt smart battery is not a smoke alarm itself, but thanks to its built-in microphone and Wi-Fi chip, it can turn any smoke alarm powered by a 9-volt battery or hardwired with a 9-volt backup into a smart one. Roost’s smart functions are also available in two hardwired alarm models, one for smoke only and another for smoke and CO, both with the Roost battery included.
Once connected with the Roost app, the battery will send you alerts when the alarm goes off. Since you tell the battery upon installation where it’s located, it can tell you where the danger is, and it will send you an alert when the alarm stops, so you know whether the danger has passed (the Nest Protect also does this). You can silence any battery-only alarm from your phone (though you can’t do the same with hardwired alarms), and you have no need to worry about 2 a.m. battery chirps—you’ll get a notification long before the battery runs out.
Once you sync the Roost battery with the app and install it in an alarm, you’ll receive alerts when an alarm goes off, as well as another alert when it stops. The Nest Protect and the Roost are the only two alarms we tested that also follow up to let you know if the danger has passed.
The Roost battery doesn’t offer any other smart features, apart from some basic IFTTT recipes, and it doesn’t integrate with other connected devices in your home, but we think Roost’s lack of extensive smart-home features is actually a plus for people who are confused or concerned about having too many IoT devices in their homes. This simplicity makes Roost a good choice for any homeowner who isn’t interested in the home-automation aspect of smart-home technology and doesn’t want to pay for such features.
The Roost 9-volt battery has a Wi-Fi radio built in.
In October 2016, Roost introduced its own line of smoke alarms, developed in partnership with Universal Security Instruments, the number three fire-safety manufacturer in the US. The Roost alarms are actually just standard alarms, but each comes with a Roost battery to add the smarts. This addition to Roost’s offerings gives you two more budget-friendly options for outfitting your home with smart smoke alarms. So, on top of retrofitting old alarms, you can buy a Roost Smart Smoke Alarm that can detect CO, all types of smoke (Roost uses a modified ionization sensor, called IoPhic, made by Universal Security Instruments), and natural gas, or you can get a cheaper smoke-only alarm. Note, however, that we don’t recommend IoPhic-based alarms due to their poor customer reviews.
The new Roost alarms are hardwired only, but with Roost batteries in them for backup (all hardwired smoke alarms have battery backups so that they will continue to work if the power goes out). The downside, as mentioned above, is that you can install hardwired alarms only where your house has wiring to support them. But if you already have a hardwired, interconnected system in your house, just one Roost battery in one wired smoke alarm will work to alert you when any of the interconnected alarms go off, making that the least expensive complete-home-retrofit option. (Battery-powered Roost-branded alarms that you can install anywhere in your home are coming soon, according to the company.)
The Roost-branded alarms are slightly more stylish than the standard Kidde and First Alert devices you might be used to, although not as attractive as the Nest Protect. They are designed to last approximately seven years (the Protect promises to last 10), while the included battery should last five years.
While Roost makes it easy and cheap to add whole-house interconnectivity to a wired system with a single battery or device, the biggest flaw in the system is its lack of wireless interconnectivity between battery-powered alarms. If one alarm loaded with a Roost battery sounds, it will bleep away sadly on its own until the danger spreads in the direction of the other alarms, but you will get an alert on your phone.
During our testing, the option to silence certain types of alarms through the app did not work well. For example, when we were cooking in the kitchen and the smoke activated the alarm, a full 45 seconds passed before the alert came up on our phone to let us silence it. By that point we had already grabbed a kitchen stool and pressed the silence button on the alarm itself.
None of the Roost options offer voice alerts, but a push notification on your smartphone will tell you where the danger is. Roost can also notify an emergency contact—a monitor, as Roost calls it—when the alarm goes off. That person just needs to download the app and create their own account, and then they’ll be linked to your alarms. You can set up multiple monitors through the Roost app.
About smart alerters
A smart alerter such as the Leeo plugs into your wall and listens for the sound of smoke and CO alarms. It then sends you an alert.
If you already have a house full of smoke alarms that you don’t want to replace or install $35 batteries into, you have another option for getting notifications when your alarms go off: plug-in alerters. Such a device plugs into a wall outlet, connects to your Wi-Fi network, and listens for the standard smoke alarms you already have. When it hears one, it sends you a notification. The main difference between these devices and the Roost battery is that they plug into an outlet, so when the power goes out they no longer work. Also, at $50 each (and you need one for each floor unless you have interconnected alarms), the Roost battery may still be cheaper. For these reasons, we think the Roost battery is the better option.
We tested two of these alerters, the Leeo Smart Alert ($50 currently) and the Kidde RemoteLync Monitor ($100 currently), and the Leeo was the clear winner, hearing every test alarm and real alarm we triggered and alerting us considerably faster than the Kidde. It also calls you if you don’t respond to its notification, something the Kidde doesn’t do. When the Leeo notifies you, it plays what it heard and asks you to confirm whether the sound is an alarm. If so, it offers to put you through to 911 or text you the number of your local fire department. The Kidde, on the other hand, merely sends you a push notification that you can easily miss. (Tip: For any smart smoke alarm or alerter, turn on the Alert setting for the app in your phone so that any notification requires a dismissal from you, making sure that you see it.)
As a bonus, the Leeo is a good-looking night-light, with a ring of colored LED lights that you can adjust in the app to any color or brightness you want. You can also set the lights to turn off when the device senses an increase in ambient light, saving energy. By comparison, the Kidde is a basic, unattractive white plastic box. The Leeo’s LED lights also glow red and pulse when it hears an alarm.
The Leeo senses temperature and humidity, too, allowing you to view a 24-hour, seven-day chart of the readings in the app and to set up notifications if the temperature or humidity goes outside preset ranges. However, the humidity readings of the two Leeo devices we tested were way off, and that appears to be a common owner complaint, especially for people who live in a humid climate (our testing was in South Carolina in the summer). Despite this issue, the Leeo did an excellent job of alerting us to the alarms in the home we were testing.
Neither of the alerters we tested is sensitive enough to reliably respond to alarms sounding a floor away, so if you don’t have interconnected alarms that sound all at once and you want complete coverage, you’ll need one for each floor of your home.
The First Alert Onelink looks similar to the Nest Protect and has many of the same features, but in our tests it was slower to send out alerts than any other alarm.
Seemingly cut from the same cloth as Nest’s Protect, the First Alert Onelink has the same ring of LED lamps to alert you to danger (red) or malfunctions (yellow), offers both voice and location alerts, and lets you silence alarms through its dedicated app. However, many of the Onelink’s features are just pale imitations of the Protect’s offerings, and we were particularly unimpressed with the full two minutes it took to push alerts to our phone and allow us to silence the alarm. The Protect took well under 30 seconds.
When activated and sounding the alarm, the Onelink will announce, in a much quieter, more robotic voice, “Smoke detected in [room]. Evacuate. Evacuate.” (You can’t set a custom name for a room, as you can with the Protect.) It has only a standard photoelectric smoke sensor, it doesn’t perform self-tests or give you a heads-up before sounding the siren, and it’s compatible with only iOS phones and tablets.
The Onelink includes a 10-year sealed battery, meaning in theory you never have to replace it. You also can’t replace it—which has been a problem for a number of owners and has been discussed extensively in Amazon customer reviews of the device.
Like the Protect, the Onelink has a wireless interconnectivity feature. Unlike the Protect, however, it also offers the option of a wired interconnect system and will work with some existing wired systems, so depending on what you have installed you may be able to buy a single Onelink and give all your existing hardwired alarms some smarts. This feature could be crucial if your home is already equipped with wired First Alert detectors. We weren’t able to test this feature, but CNET notes in its review that while the alerts from a single Onelink alarm transmitted to the “dumb” ones dependably, signals going the other way were very slow, with alerts sometimes taking up to two minutes.
The Onelink is the only Apple HomeKit–certified smart smoke alarm available now, but due to a firmware issue it doesn’t currently work with HomeKit under iOS 10. The alarm is still fully functional, it just doesn’t support control via HomeKit, so we couldn’t test those features.
The other two currently available smart smoke alarms, the First Alert Z-Wave Smoke/CO Alarm and the Kidde Wireless Interconnected Combination Smoke and Carbon Monoxide Alarm, are “smart” only when you use them with a smart-home hub such as Wink or SmartThings. If you already have one of those two systems in your home (or plan to put together a system using one of them), these alarms could be a good option.
The First Alert Z-Wave Smoke/CO Alarm (ZCOMBO) was our favorite of the two alarms that work with a smart-home hub. We tested it with SmartThings, but it’s compatible with other Z-Wave systems apart from Wink. The SmartThings app interface is a lot more intuitive than the Wink/Kidde version, offering a useful alert screen when the alarm goes off, where you can interact with all your connected smart devices activated by the alarm (as opposed to just getting a notification from Wink). You can also silence the alarm from there, which you can’t do with Wink.
However, although you get some useful smarts if you have other connected devices in your home, you don’t get any additional smoke-sensing ability over a standard alarm (First Alert uses a photoelectric sensor), voice alerts, self-testing, or any wireless interconnectivity features. The device itself is pedestrian in design, looking just like a regular smoke alarm. It doesn’t come in a wired version, so you can’t connect it to a wired, interconnected system. It operates on two AA batteries, and the SmartThings app has no battery-alert setting, so it doesn’t do away with late-night battery chirps.
On the positive side, if you have compatible cameras, lights, locks, and a sound system, you can set up automatic routines to record footage, turn your lights red, unlock your doors (so that the fire department doesn’t break them down), and have your compatible sound system say “Fire alarm” if triggered. Without any of those devices in your home, however, you will merely receive a push notification that an alarm has gone off.
Because it’s often offered at a discount in multi-packs, the Kidde Wireless Interconnected Combination Smoke and Carbon Monoxide Alarm is the least expensive smart smoke alarm, albeit with the least flexibility and features. It is nicer looking than the First Alert Z-Wave model, with smooth corners and an elegant rounded shape, but it doesn’t come in a wired version, it has only an ionization sensor, and it operates on three standard AA batteries, meaning low-battery chirps are still a possibility. It also works as a smart alarm only if you connect it to the Wink smart-home hub.
The Kidde alarm’s best feature, and its biggest advantage over the First Alert, is that a number of them can interconnect wirelessly, and you don’t need a hub for that functionality. However, because this model is ionization only, you will need another one, a photoelectric smoke alarm, in your home (especially in the kitchen, where Kidde says you should not put this alarm). It also offers basic voice alerts (“Fire!” “Carbon Monoxide!”), but it doesn’t tell you which room the danger is in, and because they all go off at once, you may have trouble tracking down the problem.
Once you connect it to Wink, you can set up Robots to trigger other smart-home devices to act if an alarm is activated, but the Wink app integration is limited—you can set up low-battery alerts and receive notifications if your alarms are activated, but that’s pretty much it. You can’t silence the alarm from the app, and many customer reviews complain that Wink didn’t always trigger their Robots when an alarm went off, rendering the smart-home integration useless.
What to look forward to
In its guide to smoke and CO alarms, Consumer Reports issues a challenge to all smoke alarm manufacturers to create “a single device that senses both kinds of fire and CO.” The Nest Protect’s Split-Spectrum Sensor purports to cut down nuisance alarms by including a type of ionization sensor, but it isn’t a dual detector. However, two smart smoke alarms coming soon promise to offer true dual-sensing smoke detection, with both photoelectric and ionization sensors.
Halo Smart Labs’s Halo incorporates sensors that detect all types of fires, as well as CO. It also offers voice alerts and a glowing red ring to indicate danger, plus a 10-year battery. A second unit, the Halo +, incorporates weather and disaster alerts, covering tornadoes, floods, and hurricanes. Halo Smart Labs told us that the devices will be shipping in December.
Birdi distinguishes itself by offering air-quality and weather monitoring in addition to providing dual smoke sensing and CO detection. According to its website, Birdi tracks dust, VOCs, temperature, and humidity, as well as how stale the air is inside your home. Outside, it tracks pollution, pollen, and particulates, and provides weather tips. According to the Birdi blog, it will be shipping in late November, and it is an Apple HomeKit partner.
Speaking of HomeKit, as we mention above, First Alert’s Onelink is technically HomeKit compatible, meaning you should be able to set up automations to trigger when your alarm detects smoke or CO. However, due to a firmware issue this functionality isn’t currently available with iOS 10 and the Home app. A fix is coming soon, according to the makers of the Onelink, and once it arrives we’ll update our review. In the meantime, you can still use Siri to ask questions such as “Is there smoke upstairs?” or “How is the carbon monoxide alarm?” But we imagine the usefulness of this function is pretty limited.
( By JENNIFER PATTISON TUOHY )