Last updated: October 2026
A smoke alarm that only screams at the ceiling is doing half the job. The best smart smoke detector also sends the alert to your phone, tells you whether the danger is smoke or carbon monoxide, and can wake up the rest of the house when one unit trips. That last part matters most when a fire starts while you are asleep or away from home.
The category shifted in 2025. Google discontinued the Nest Protect, the device that basically defined the smart smoke alarm, and pointed owners toward a First Alert replacement instead. At the same time, Apple Home finally started supporting smoke and CO alarms through Matter, which opened up a genuinely local, HomeKit-friendly option for the first time. So the picks below look different from a list you might have seen a year ago.
We focused on combination smoke and carbon monoxide units where possible, since most homes need both and a single device on the ceiling is easier to live with than two. Here is how the current field stacks up, from the best overall smart smoke and carbon monoxide detector to the best Matter option for Apple households. If you are still deciding whether the upgrade is worth the cost, our guide on whether smart smoke detectors are worth it weighs the benefits against a good regular alarm.
Quick Recommendations
- Best overall: First Alert SC5: the official Nest Protect successor, combination smoke and CO, Google Home support.
- Best for Ring and Alexa homes: Kidde Smart Alarm with Ring: alerts land in the Ring app, no separate hub needed.
- Best standalone Wi-Fi alarm: Kidde Smart Alarm (Kidde app): works with Alexa and Google Home, the most flexible best wifi smoke detector here.
- Best for Apple Home and Matter: Heiman Matter Smoke Alarm: Matter over Thread, appears natively in Apple Home, and reports room temperature and humidity too.
- Best Matter carbon monoxide alarm: Heiman Matter CO Alarm: the local, multi-platform companion for CO coverage.
At-a-Glance Comparison
| Product | Ecosystem | Key Feature | Approx. Price | Best For |
|---|---|---|---|---|
| First Alert SC5 | Google Home, First Alert app | Nest Protect replacement, voice location alerts | ~$130 | Best overall |
| Kidde with Ring | Ring, Alexa | Alerts in the Ring app, no hub | ~$75 | Ring and Alexa homes |
| Kidde (Kidde app) | Alexa, Google Home | Standalone Wi-Fi, voice status checks | ~$75 | Flexible Wi-Fi setup |
| Heiman Smoke (S1-TM) | Apple Home, Google, Alexa, SmartThings | Matter over Thread, temperature + humidity sensor | ~$50 | Apple Home and Matter |
| Heiman CO (C1-M) | Apple Home, Google, Alexa, SmartThings | Matter over Thread CO alarm | ~$60 | Matter CO coverage |
Compatibility Matrix
| Product | HomeKit | Alexa | Google Home | Matter | Thread | Hub Required | Wiring/Power |
|---|---|---|---|---|---|---|---|
| First Alert SC5 | No | Not stated | Yes | No | No | No (Wi-Fi) | Battery or hardwired |
| Kidde with Ring | No | Yes (alerts on Echo) | No | No | No | No (Wi-Fi) | Hardwired + AA backup |
| Kidde (Kidde app) | No | Yes | Yes | No | No | No (Wi-Fi) | Hardwired + AA backup |
| Heiman Smoke (S1-TM) | Yes (iOS 18.4+) | Yes | Yes | Yes | Yes | Thread border router | CR123A battery |
| Heiman CO (C1-M) | Yes (iOS 18.4+) | Yes | Yes | Yes | Yes | Thread border router | CR123A battery |
Two things decide most of this. If you want the alarm to show up in Apple Home, only the Matter over Thread units qualify, and they need a Thread border router such as a HomePod mini or Apple TV 4K on your network (if you are not sure what that means, here is whether you need a HomeKit hub). If you are on Ring, Alexa, or Google Home instead, the First Alert and Kidde Wi-Fi units connect directly without a hub. Our guide to the best Matter hubs lists the devices that double as a Thread border router.
The Best Smart Smoke and Carbon Monoxide Detectors
First Alert SC5 Smart Smoke & Carbon Monoxide Alarm — Best Overall
When Google stopped making the Nest Protect, the SC5 is the device it steered people toward, and it is the best smart smoke detector you can buy right now if you want one polished, do-everything unit. It combines photoelectric smoke sensing with an electrochemical CO sensor in one unit, and it talks to the Google Home app so alerts and silencing sit alongside your other Google devices.
Best for: Households that want one polished combination alarm and already use Google Home or Nest.
What stands out
The SC5 handles the two things older alarms did badly. It tells you what the problem is and where it is, using voice Heads-Up alerts instead of a single undifferentiated shriek, and it pushes that same information to your phone through the First Alert app when you are out. It also interconnects, so when one unit senses smoke, every compatible alarm in the home sounds. Precision Detection is First Alert’s answer to nuisance trips from cooking steam, which is the usual reason people disable an alarm they should not.
Key specs
- Combination photoelectric smoke + electrochemical CO
- Voice and location alerts, app notifications
- Interconnects wirelessly with up to 18 SC5 and Nest Protect alarms
- Battery and hardwired versions, battery backup on both
Pros
- The closest thing to a direct Nest Protect replacement
- Clear voice alerts that name the hazard and room
- Works in the Google Home app
- Reuses the Nest Protect mounting bracket
Cons
- Expensive at around $130 per unit
- No Apple HomeKit support, and Alexa support is not confirmed
- Overkill if you only want basic phone alerts
Installation and compatibility notes
Setup runs through the First Alert app and takes a few minutes, with batteries preinstalled. The alarm links into Google Home for alerts and silencing, but it is not a HomeKit device and does not use Matter. If you are replacing a Nest Protect, the SC5 uses the same bracket and includes a quick-connect adapter for hardwired swaps.
Price: ~$130
Kidde Smart Smoke + Carbon Monoxide Alarm with Ring — Best for Ring and Alexa Homes
If your smart home already runs through Ring and Alexa, this Kidde combination alarm is the cleanest fit. It connects to your Wi-Fi and reports smoke, CO, and low-battery status directly in the Ring app, with no Ring Alarm base station or separate hub required.
Best for: People invested in Ring and Alexa who want fire and CO alerts in the same app as their cameras.
What stands out
Everything shows up where you already look. Instead of a chirp you have to hunt down, a low battery becomes a Ring app notification, and a real alarm reaches your phone wherever you are. Because it is hardwired with AA backup, it keeps working through a power cut, and it interconnects with compatible Kidde alarms so the whole house sounds together. Kidde rates its current sensor as noticeably faster at catching smoldering fires than the previous generation. If your home already has hardwired, interconnected alarms, one Kidde smart unit on that circuit is enough to get phone alerts when any of them sounds.
Key specs
- Combination photoelectric smoke + electrochemical CO
- Ring app alerts over Wi-Fi, no hub needed
- Hardwired with AA battery backup
- Interconnectable with compatible Kidde alarms
Pros
- Alerts land in the Ring app alongside your other devices
- No subscription required for the core alerts
- Reliable hardwired power with battery backup
- Straightforward for existing Ring users
Cons
- Hardwired install suits replacement of an existing wired alarm best
- Tied to the Ring app, so less ideal outside that ecosystem
- No HomeKit or Matter support
Installation and compatibility notes
You set it up in the Ring app, which is also where alerts and battery warnings appear. It connects straight to home Wi-Fi and does not need an existing Ring alarm or bridge. An optional Ring subscription ($5 a month) adds 24/7 professional monitoring and emergency dispatch, but the smoke and CO alerts themselves do not require one. Alexa can announce its alerts on Echo devices. No wiring at the ceiling? Kidde also makes a battery-powered version with Ring (~$70) that interconnects wirelessly with other Kidde alarms.
Price: ~$75
Kidde Smart Smoke + Carbon Monoxide Alarm (Kidde App) — Best Standalone Wi-Fi Alarm
This is the same class of Kidde hardware routed through Kidde’s own app instead of Ring, and it is the most flexible best wifi smoke detector on the list. It works with both Amazon Alexa and Google Home, so you are not locked into one voice platform.
Best for: Anyone who wants a smart combination alarm with app alerts but does not use Ring.
What stands out
The appeal here is neutrality. You get the same Wi-Fi alerts and low-battery notifications, but you can check status by voice through either Alexa or Google Home. For a mixed household where one person is on Alexa and another leans Google, that flexibility is genuinely useful, and it makes this the easiest best smart smoke alarm to slot into an existing setup.
Key specs
- Combination photoelectric smoke + electrochemical CO
- Wi-Fi alerts through the Kidde app
- Works with Alexa and Google Home
- Hardwired with AA battery backup, interconnectable
Pros
- Works with both Alexa and Google Home
- No hub or bridge required
- Same fast Kidde sensor as the Ring version
- App alerts and voice status checks
Cons
- No HomeKit or Matter support
- Hardwired install is easiest as a wired-alarm replacement
- Kidde app is functional rather than polished
Installation and compatibility notes
Setup is through the Kidde app over 2.4 GHz Wi-Fi. Link it to Alexa or Google Home for voice status, and interconnect it with compatible Kidde units so alarms sound together. It is a combination smoke and CO alarm, so a single device covers both hazards on that part of the ceiling.
Price: ~$75
Heiman Matter Smoke Alarm (S1-TM) — Best for Apple Home and Matter
This is the pick that finally makes a smoke alarm work properly with Apple Home. The Heiman S1-TM speaks Matter over Thread, so with iOS 18.4 or later it appears natively in the Home app as an alarm accessory, alongside Google Home, Alexa, SmartThings, and Home Assistant. It is the same alarm as Heiman’s earlier S1-M with a temperature and humidity sensor added, and it is the version Heiman now sells on Amazon.
Best for: Apple Home users, and anyone who wants a local alarm that is not tied to a single manufacturer’s cloud.
What stands out
Because it runs on Thread and Matter, the S1-TM reports locally with no vendor cloud in the middle, which is both faster and more private than a Wi-Fi alarm phoning home. In Apple Home it can trigger automations, so a smoke event can flip on the lights or shut down a fan without extra bridges. It is also seriously certified: UL 217 10th Edition plus a California State Fire Marshal listing, with a dual-beam photoelectric sensor aimed at cutting kitchen false alarms. The built-in temperature and humidity readings also show up in your smart home app, so the alarm doubles as a room climate sensor. It is smoke only, so pair it with the CO alarm below for full coverage.
Key specs
- Photoelectric smoke sensor, dual-beam, UL 217 10th Edition
- Matter over Thread, local operation
- Replaceable CR123A battery (included)
- Built-in temperature and humidity sensor
- Compact, battery-powered, 85 dB siren
Pros
- Genuine Apple Home support through Matter (iOS 18.4+)
- Also works with Google, Alexa, SmartThings, Home Assistant
- Local and private, no manufacturer cloud
- Affordable at around $50
Cons
- Smoke only, no built-in CO sensor
- Requires a Thread border router on your network
- No built-in interconnect: other alarms only sound through an automation you set up
- Sold through the manufacturer’s storefront rather than a big brand
Installation and compatibility notes
You need a Thread border router such as a HomePod mini or Apple TV 4K for it to join Apple Home, which most HomeKit households already have. Add it in the Home app like any Matter accessory. For carbon monoxide, pair it with the Heiman CO alarm below, since this unit does not detect CO on its own. If you are new to Matter and Thread, our guide to Zigbee vs Z-Wave vs Matter explains how the pieces fit together, and Matter vs Thread covers the difference between the two.
Price: ~$50
Heiman Matter Carbon Monoxide Alarm (C1-M) — Best Matter Carbon Monoxide Alarm
Carbon monoxide is the hazard people forget until winter, and this is the local, Matter-native way to cover it. The Heiman C1-M is the companion to the S1-TM smoke alarm, using the same Matter over Thread approach so both show up in the same app and can drive the same automations.
Best for: Apple Home and Matter users who want dedicated CO detection to go with a Matter smoke alarm.
What stands out
Pairing the C1-M with the S1-TM gives you smoke and CO coverage that both live locally in Apple Home, Google Home, Alexa, or SmartThings, without a manufacturer cloud in between. Keeping CO on its own sensor is not a downside: a CO alarm belongs outside each sleeping area and near fuel-burning appliances, which is not always where a smoke alarm goes, so separate units let you put each one where it is needed.
Key specs
- Electrochemical carbon monoxide sensor, UL 2034 5th Edition
- Matter over Thread, local operation
- CR123A battery rated up to 10 years, wall or ceiling mount
- Real-time app notifications and automation triggers
Pros
- True Matter CO alarm with Apple Home support (iOS 18.4+)
- Works across Google, Alexa, SmartThings, Home Assistant
- Local and private, pairs cleanly with the S1-TM
- Small enough to put near bedrooms, furnaces and water heaters
Cons
- CO only, needs the smoke alarm alongside it
- Requires a Thread border router
- Sold through the manufacturer’s storefront
Installation and compatibility notes
Like the smoke alarm, it needs a Thread border router and gets added in your Matter platform of choice. Mount it on a wall or ceiling outside the bedrooms, following the placement guidance in the manual. Carbon monoxide is slightly lighter than air and mixes through the room, so it does not need to sit near the floor. Together with the S1-TM it forms a complete local smoke and CO pair for Matter homes.
Price: ~$60
Other Options We Considered
- Ring Smoke & CO Listener (~$40): a small add-on that listens for the siren of the alarms you already have and sends a phone alert through the Ring app. The current version no longer needs a Ring Alarm base station. A good fit for renters, but it only works when an existing alarm sounds, so it does not add detection.
- X-Sense Wi-Fi alarms: affordable smoke and CO alarms with app alerts, but many of the smart models connect through an X-Sense base station, and the Amazon combo listing we checked was sold by a reseller rather than Amazon or X-Sense.
- Heiman S1-M: the original Heiman Matter smoke alarm, without the temperature and humidity sensor. Its Amazon listing is gone, so the S1-TM above takes its place.
How to Choose a Smart Smoke and CO Detector
Combination or separate units. A combination alarm covers smoke and carbon monoxide in one device, which is simpler and cheaper for most rooms. The exception is the Matter route, where smoke and CO are still sold as separate sensors, letting you put CO detection near bedrooms and fuel-burning appliances without doubling up on smoke alarms.
Photoelectric sensing. Every pick here uses a photoelectric smoke sensor, which is better at catching slow, smoldering fires and less prone to nuisance alarms from cooking than older ionization sensors. Look for a UL 217 listing from the 8th Edition onward, which added tests to cut cooking false alarms. The newer 10th Edition (published 2024, required for listings from November 2027) keeps those tests, and the Heiman alarm already carries it.
How it connects. Wi-Fi alarms like the First Alert and Kidde units are the easiest to set up and need no hub, but they depend on the manufacturer’s cloud and your router. Matter over Thread alarms are local and appear natively in Apple Home, but they need a Thread border router. Z-Wave combination alarms exist for SmartThings and Ring Alarm hubs, though they are harder to find on major retailers right now.
Power and interconnect. Hardwired alarms with battery backup suit direct replacement of existing wired detectors, while battery-only units go anywhere. If you want every alarm in the house to sound at once, check that your chosen units interconnect, either physically or through the app. Matter alarms do not interconnect on their own yet; you set that up as an automation in your smart home app.
Match it to your ecosystem. This is the part that saves you grief, because the best smart smoke detector for your home is really the one that fits the platform you already use. Pick the First Alert SC5 for Google Home, either Kidde for Ring or a mixed Alexa and Google home, and the Heiman Matter units for Apple Home. Buying against your ecosystem is the fastest way to end up with an alarm whose smart features you never use.
Final Recommendations
For most people, the First Alert SC5 is the best smart smoke and carbon monoxide detector overall: it is the natural Nest Protect replacement and handles smoke and CO in one polished unit. Ring and Alexa households should take the Kidde with Ring, while the Kidde app version is the better pick if you want a flexible Wi-Fi alarm that answers to both Alexa and Google Home. Apple Home users finally have a real answer in the Heiman Matter smoke alarm, ideally paired with the matching Matter CO alarm for complete, local coverage. If you are layering in more local safety sensors, our roundup of the best smart door sensors covers the next piece, and our guide to the best water leak detectors covers leaks under sinks and behind appliances.
What is the best smart smoke detector in 2026?
For most homes the First Alert SC5 is the best overall smart smoke and carbon monoxide detector, since it replaces the discontinued Nest Protect and combines smoke and CO sensing with Google Home support. Apple Home users are better served by the Heiman Matter smoke alarm.
Is the Nest Protect still available?
No. Google discontinued the Nest Protect in 2025 and now points owners toward the First Alert SC5 as a direct replacement. The SC5 reuses the Nest Protect mounting bracket and works with the Google Home app.
Do any smart smoke detectors work with Apple HomeKit?
Yes, but only through Matter. With iOS 18.4 or later, Matter over Thread alarms like the Heiman S1-TM appear natively in the Apple Home app. They need a Thread border router such as a HomePod mini or Apple TV 4K.
Should I get a combination smoke and CO alarm or separate units?
A combination alarm is simpler and cheaper for most rooms and covers both hazards in one device. Separate units make sense on the Matter route, where they are sold individually, and let you put the CO sensor near bedrooms and fuel-burning appliances.
Do smart smoke detectors need a hub?
Wi-Fi models from First Alert and Kidde connect directly to your router with no hub. Matter over Thread models do need a Thread border router, and Z-Wave combination alarms need a compatible SmartThings or Ring Alarm hub.
What is the best wifi smoke detector without Ring?
The Kidde combination alarm that runs on the Kidde app is the best wifi smoke detector for people who do not use Ring, because it works with both Amazon Alexa and Google Home and needs no hub.
Written by Evan Mercer
Founder & Lead Researcher, Smart Home Matrix
Evan digs through spec sheets, firmware changelogs, and thousands of owner reviews so you don’t have to. Every guide starts with a compatibility check and ends with picks he would install in his own home. Read more about Evan and this site, or see exactly how we choose products.