Smoke and carbon monoxide alarms are the cheapest safety device in your house and the easiest to install yourself. The smart versions add phone alerts, remote testing, voice warnings that name the hazard and location, and whole-home interconnect so one alarm wakes every room.
Our three best picks right now: the Kidde Smart Smoke and CO Detector RGCUDR-RW for most people, because it is the only unit here that pushes smoke and CO alerts to your phone with no subscription and no separate hub. The Kidde Smart CO and Indoor Air Quality Monitor comes second if you want carbon monoxide detection plus TVOC and humidity readings from one plug-in unit. The eufy Security Smoke Alarm E10 is third, and its compact 70 mm body nearly disappears on a ceiling, though it detects smoke only and needs an eufy HomeBase to run.
The rest of this guide covers all six connected alarms we analyzed, how to place them, how many your house needs, and where the app-based features genuinely help versus where they are just marketing. We also cover the smart-speaker route in our smart smoke detector guide for anyone who wants alerts without replacing every alarm in the house.
Top 3 Picks for Smart Smoke and CO Detectors
Kidde Smart Smoke and CO RGCUDR-RW
- Smoke and CO in one unit
- Ring app alerts with no subscription
- Wire-free interconnect
- UL 217 certified
Kidde Smart CO and Air Quality Monitor
- Electrochemical CO sensor
- TVOC and humidity tracking
- Plug-in with QR setup
- Alexa and Google Home
eufy Security Smoke Alarm E10
- 70 mm compact body
- UL 217 10th edition
- 5-year sealed lithium battery
- Up to 656 ft range
Best Smart Smoke and CO Detectors (October 2026)
| Product | Specifications | Action |
|---|---|---|
| Kidde Smart Smoke and CO RGCUDR-RW |
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| Kidde Smart CO and Air Quality Monitor |
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| eufy Security Smoke Alarm E10 |
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 Heiman S1-R Interconnected Smoke 3-Pack |
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 Heiman C1-R Smart CO 3-Pack with Gateway |
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 Kidde Smart Plug-In CO Detector COPDW |
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1. Kidde Smart Smoke and CO Detector RGCUDR-RW
- Only pick here with smoke and CO alerts and no subscription
- Wire-free install on included AA batteries
- Linked alarms all sound together so one unit wakes the house
- Enhanced sensing tuned to cut cooking nuisance alarms
- Low-level CO mobile alerts
- Connectivity features need troubleshooting after a Wi-Fi change
- Reset procedure is finicky on a new network
- Professional monitoring is only available as a paid add-on
This is the unit I keep coming back to, because it solves the exact problem most people hit when they upgrade: they want a phone alert when something goes wrong, and they do not want a subscription attached to it. You download the Ring app, scan the code on the unit, and smoke, carbon monoxide and low-battery warnings arrive without paying anything.
It handles both hazards in one case, which halves the number of devices on your ceiling and means one mounting hole. Power comes from two included AA alkaline batteries, so there is no wiring to trace and no electrician if you live in a rental or an older house without a box in the ceiling.
Kidde claims detection more than 25 percent faster than a leading competitor based on internal testing, and owners in the reviews back up the general direction of that claim by noting fewer cooking-related nuisance alarms than older units they replaced. It is certified to UL 217 and FCC standards, so it clears the listing requirements that fire departments and local codes actually enforce.
The interconnect is the part I value most. When one unit senses smoke or CO, the linked units all sound, which matters in a multi-storey house where a single alarm on the top floor does nothing for a sleeping family downstairs. Add a subscription-free professional monitoring plan later through Ring if you want a call from a monitoring center, but it is genuinely optional.
When this model fits your home
This suits renters, apartments without wiring, and any home where you want dual-hazard coverage with phone alerts on a free tier. It also works in a cabin or an older house with no hardwired box, and owners who travel appreciate that the alerts keep arriving while nobody is home.
For a house with existing hardwired interconnects, note that this is a battery unit. It will not slot into a wired run as a connected replacement without other changes, so plan on running it as a separate wireless network rather than mixing it into the old line.
Where it disappoints
The honest weakness is connectivity, not sensing. Reviewers repeatedly describe needing to troubleshoot or reset the Wi-Fi connection after a router change, and the reset steps are not as painless as they should be. Plan to do the install when your network is stable rather than the day your internet provider changes.
There is also no digital readout of CO concentration. You find out that there was a level, or you find out nothing. For most families that is fine, but if you want a running ppm number to watch during a cold snap, look at the plug-in Kidde unit further down instead.
2. Kidde Smart Carbon Monoxide Detector and Indoor Air Quality Monitor
- CO detection plus TVOC and humidity in one plug-in unit
- Voice alarm announces the hazard type
- QR code setup takes a couple of minutes
- Works with Alexa
- Google Home
- iPhone and Android
- Tolerates up to 95 percent relative humidity
- Temperature and humidity readings can run noticeably off
- TVOC values swing and converge across units
- Placement is dictated by where your outlets are
The pitch here is breadth. Alongside the electrochemical CO sensor, this unit tracks total volatile organic compounds and humidity, so you can see when a paint project or a run of new furniture is affecting the air in a nursery or a small bedroom. That is a real benefit in tight spaces where ventilation is poor.
Setup is the easiest of any connected alarm here. Download the Kidde app, scan the QR code and plug it into a standard outlet. The voice alarm announces the hazard type when it trips, which is helpful at three in the morning when nobody can tell a low-battery chirp from an actual problem.
Dimensions are 1.5 inches deep by 3 inches wide by 5.5 inches high and it weighs 8 ounces, so it does not project off the wall the way a lot of plug-in CO units do. Kidde backs it with a 10-year limited warranty, which lines up with the expected service life of the sensing element.
Owners consistently like being able to add several of these around the house on the same account and interconnect them, so a bedroom, a hallway and a finished basement can all talk to each other. Compatibility covers Android, iPads, iPhones on iOS 12 or newer, plus Alexa and Google Home.
When this model fits your home
Choose it if carbon monoxide is your main worry and you also want a rough read on indoor air quality. It suits a home office, a child’s room or a renovation in progress where paint solvents and cleaning products are the thing you actually want to track.
It is a good match for anyone already in the Alexa or Google Home ecosystem who does not want a separate hub. Since it draws power from the wall, it also keeps working through a power outage for as long as your circuit stays live, which removes one failure mode you would otherwise worry about.
Where it disappoints
This is a CO detector with extra sensors, not a smoke alarm. If you are building a full coverage plan, you still need photoelectric smoke units on every level, and several buyers looking for one box that does both jobs end up disappointed.
The environmental readings are the weak spot. Reviewers report temperature and humidity values running noticeably off against reference devices, and TVOC numbers that swing widely and tend to converge across several alarms on the same network.
Treat those numbers as a trend indicator rather than an instrument reading. Plug-in placement is also fixed by your outlets, and one detailed review reports a unit that stopped powering on after roughly five months before a quick replacement from Kidde support.
3. eufy Security Smoke Alarm E10
- Compact 70 mm body
- much smaller than a traditional alarm
- 4.4 average rating from 221 owners
- UL 217 10th edition compliant sensing
- Five-year sealed battery with no low-battery chirp
- 656 ft wireless range from the hub
- Requires a separately purchased eufy HomeBase hub
- Hub firmware must be on a supported version
- Smoke only with no CO sensing
At 70 mm across, eufy describes it as roughly a third the size of a traditional alarm, and it does disappear on a ceiling in a way most units never do. If you have ever pulled a chunky old detector off a hallway ceiling and repainted the outline it left behind, the slim eufy body solves that problem.
Detection meets UL 217 10th edition, the current standard for residential smoke alarms. It uses a sealed lithium battery rated for five years with no low-battery chirp to wake the house at night, and wireless range reaches up to 656 feet from the hub in open space.
Satisfaction runs high, with 76 percent of owners giving five stars. The consistent praise is about the form factor and the battery. The consistent complaint is about what you have to buy first: this unit will not operate without an eufy HomeBase.
Which HomeBase works matters. The listing calls for HomeBase Mini on firmware 4.0.5.2 or later, HomeBase 2 on 3.4.1.2 or later if it shipped after 2021, HomeBase 3 on 3.7.2.6 or later, or HomeBase Pro on 4.1.4.3 or later. Check what you already own before you order, because an older hub on old firmware will simply not pair.
When this model fits your home
This is the pick for someone already invested in the eufy security system, where the alarm plugs into the hub they own and reports in the same app as their cameras and doorbells. It suits low ceilings, small bedrooms and rentals where a visible alarm has to be unobtrusive.
It also works as a wide-coverage smoke layer because of that 656-foot range, which means a handful of alarms can cover a long hallway or an open-plan floor without a hub in every room. At 3.52 ounces it is easy to mount on a high ceiling without a second pair of hands.
Where it disappoints
Two limits are worth being blunt about. First, it senses smoke and nothing else, so carbon monoxide still needs its own coverage, and a smoke alarm sitting in a garage or a utility room is wasted money.
Second, the five-year sealed battery is shorter than the ten-year claims common in this category, and the hub dependency is a real cost and a real single point of failure. If your internet goes down, the local siren still sounds, but the phone alerts stop, and that is the tradeoff you accept when you buy into a closed hub system. Firmware updates for the hub are a recurring chore as well.
4. Heiman S1-R Interconnected Photoelectric Smoke Detector 3-Pack
Heiman Smoke Detector, Wireless Interconnected Smoke Alarm for Home, 3 Pack
- No account
- no app and no hub required
- Three alarms give instant whole-home coverage
- Dual photoelectric sensing resists steam and cooking fumes
- Magnetic mounts make battery changes quick
- UL 217 10th edition certified
- Red Dot Design Award winner
- No phone alerts of any kind
- A few owners report the sealed battery dying early
- Some buyers were unsure the units truly interconnect
- No CO sensing
This is the one to buy if you want interconnected alarms and nothing else. There is no app to create, no account to verify, no hub to keep on firmware and nothing to subscribe to. You mount all three, and when one senses smoke the other two sound as well.
Detection is dual-beam photoelectric, tuned toward faint and smoldering smoke. That chamber design is also what resists nuisance alarms from shower steam and cooking vapor, which are the two things that drive people to disable the alarm in their own home.
Certification is UL 217 10th edition, and the housing is ABS plus PC rated UL94 V-0 for flame resistance. The buzzer puts out 85 dB at 10 feet alongside LED indicators, and a one-touch test button doubles as a 10-minute silence control.
Installation is genuinely quick. Each alarm comes with a lithium battery, and you can fix each one with screws, magnetic pads or adhesive. The 2.75-inch body is compact, and owners whose local fire departments require photoelectric alarms note that these satisfy the requirement.
When this model fits your home
It suits a three-bedroom single-storey house where you want every alarm to trigger every other alarm, especially if you have young children, older parents or a heavy sleeper who needs the whole house woken up. It is also a good fit for anyone tired of handing personal data to a detector manufacturer.
Because the interconnect is wireless with a range up to 656 feet in open areas, it works in a multi-storey home where running interconnect wire would mean opening walls. The magnetic mounts also mean a battery change takes seconds rather than a ladder.
Where it disappoints
The absence of connectivity is not a bug, but you should be clear about what you give up. There are no phone notifications, no remote test, no remote silence and no history. If you travel often and want to know your home is fine, this is the wrong product.
It also detects smoke only, so it does nothing for carbon monoxide. And a small cluster of owners questions the sealed battery life after only a year or two, which is worth factoring in if you are planning coverage without a way to check battery status remotely. A few buyers were also unsure the units linked as advertised, so test the interconnect yourself the day you install them.
5. Heiman C1-R Smart CO Detector 3-Pack with Gateway
Heiman Smart Carbon Monoxide Detectors, 3-Pack Interconnected, with Gateway
- Three detectors plus a gateway cover a whole home
- Explicit Home Assistant
- IFTTT
- Google Home and SmartThings support
- FIGARO sensor rated linear to 5000 ppm
- App shows status
- battery level and alarm history
- Gateway also triggers leak and door sensors
- No live ppm readout on the detectors
- Gateway is 2.4 GHz only and can pair slowly
- Units do not operate below 40 degrees Fahrenheit
- Batteries are replaceable rather than sealed
This is the only unit in our group that names Home Assistant, IFTTT, Google Home and SmartThings directly on the spec sheet. If your alarm system runs on a local automation hub rather than a cloud account, that matters more to you than it would to anyone else.
The sensing element is a Japan-made FIGARO TGS5141 electrochemical sensor, and the listing claims 10-year linear accuracy across a 0 to 5000 ppm range. That sensor chemistry is also why it holds up near humidity and temperature swings where cheaper cells drift.
The bundle contains three CO alarms and a gateway on the 2.4 GHz Wi-Fi band. One detection sounds every linked alarm and pushes an alert through the Heiman Home app, where you can check status, battery level and the alarm log. The same gateway also pairs with Heiman S1-R smoke units and leak and door sensors, so a single hub can cover more than fire safety; our water leak detector guide covers the pairing requirements in detail.
It is UL 2034 5th edition certified and CSFM approved, which is the carbon monoxide equivalent of what UL 217 means for smoke. Interconnect range is 656 feet, and each detector weighs 3.5 ounces with a 2.75-inch square face.
When this model fits your home
Start here if you run Home Assistant and want carbon monoxide alerts in your dashboards and automations without a cloud round trip. It is also the natural companion to the Heiman smoke pack if you want one gateway serving both hazards and a leak sensor in the same kitchen.
Three detectors plus a hub is a sensible way to cover a home with CO risk points, such as a garage, a basement with a furnace and an area near a fireplace. Replaceable batteries mean you are not discarding a sealed pack at the ten-year mark on every unit.
Where it disappoints
There is no live carbon monoxide concentration readout. The detectors alarm at dangerous levels, which is the safety-critical function, but you cannot watch a ppm trend, so this pairs poorly with the Kidde unit above if a number on a screen is important to you.
Two practical constraints catch people out. The gateway is 2.4 GHz only and can be slow to pair the first time, and one buyer needed to retry the linking before SmartThings picked it up.
The detectors also do not operate below 40 degrees Fahrenheit, which rules them out of an unheated garage, a cold cabin or a detached workshop. The review base here is small, so treat the 4.4 average as promising rather than proven.
6. Kidde Smart Plug-In CO Detector COPDW
Kidde Smart Carbon Monoxide Detector, Plug-in & AA Battery Backup, COPDW
- Phone alerts with no subscription required
- Bright backlit display shows the reading clearly
- Two AA batteries keep it alive through an outage
- Rotating plug fits vertical or horizontal outlets
- Works with Alexa and Google Home
- 10-year limited warranty
- Must sit within reach of a 120V outlet
- App setup and pairing can be fiddly
- Needs a stable 2.4 GHz network
- One detailed review reports a failure to sound
The thing you notice first is the display. A bright backlit digital readout means you can check the carbon monoxide level at a glance, which is the single feature people miss most when their CO alarm chirps at two in the morning and they have to feel their way to a hallway.
It is plug-in with two included AA batteries for backup, so a short power outage does not take the alarm offline with it. Those backups also produce no low-battery chirp, because they are not the primary supply.
Certification is UL 2034 5th edition and ETL Listed, the 85 dB alarm is loud, and the rotating plug body fits both vertical and horizontal outlets. That last detail matters more than it sounds, because a rotated plug in a horizontal receptacle can stop making contact if the fit is poor.
Owners report dependable alerts across rooms and even mention carrying the unit in a bag while staying in a hotel, which tells you how small it actually is at 6.88 ounces and 1.52 by 2.9 by 5.47 inches. It integrates with Alexa and Google Home and carries a 10-year limited warranty.
When this model fits your home
This suits a bedroom, a basement or a room with a fuel-burning appliance where you want a visible reading rather than just an alarm. It is a sensible single-unit add-on to a house that already has smoke coverage but no carbon monoxide alarm at all.
It works well for anyone who wants a checkable number without buying into an ecosystem subscription, and the AA backup means it keeps reporting during the kind of outage that also takes out your internet and leaves your smart cameras dark.
Where it disappoints
Placement is fixed by your outlets, and carbon monoxide does not respect the location of a wall receptacle the way a mounted alarm would. If the nearest usable outlet is in the wrong room, you are looking for an electrician or a different product.
Setup friction in the Kidde app is the most common complaint, and the unit needs a stable 2.4 GHz network, so a mobile hotspot is an unreliable base. More seriously, one detailed negative review reports the alarm failing to sound during several gas incidents, which is rare but is the kind of report you should weigh heavily in this category. Test it with the built-in button monthly and after any network change.
How to Choose a Smart Smoke and CO Detector
Decide smoke or carbon monoxide or both
Smoke and CO are different hazards with different causes, and only one pick in our group covers both in a single case. A combination alarm halves your ceiling clutter, but a dedicated CO alarm can be placed near a fuel-burning appliance where smoke detection is pointless. Most homes benefit from both layers rather than one compromise unit everywhere.
Check the sensor type, not the marketing
Photoelectric sensing responds to smoldering fires and cooking particles, ionization responds faster to fast-burning flame, and split-spectrum units combine both. All the smoke units we reviewed use photoelectric chambers, including the dual-beam design in the Heiman pack, which is also why they tolerate shower steam better. Every CO unit here uses an electrochemical sensor, and UL 217 covers smoke alarms while UL 2034 covers carbon monoxide detectors, so confirm the matching standard on whatever you buy.
Understand hardwired versus battery power
Hardwired alarms with a battery backup never stop working because a battery died, and newer building codes require at least one hardwired alarm in many new builds. Every connected alarm in this roundup is a battery or plug-in design, so if you are building new, plan a hardwired layer plus connected alarms rather than expecting a smart battery alarm to satisfy code on its own.
Count the units your house actually needs
NFPA 72 guidance points to an alarm inside each bedroom, outside each sleeping area, on every level including the basement, and in spaces near sleeping areas such as hallways and open lofts. In practice that means roughly seven alarms for a two-bedroom, single-storey home, nine or ten for a three-bedroom, and twelve or more for a four-bedroom spread over two floors. Our whole-home smoke detector guide covers the room-by-room planning in more detail. Keep detectors at least 10 feet from a cooking appliance to avoid nuisance alarms, and away from bathroom doors where steam travels.
Decide how much connectivity you actually need
Free app alerts, subscription professional monitoring, and no connectivity at all are all legitimate choices. A monitoring plan gives you a phone call from a call center while your own phone alerts give you a push notification. Our smart smoke detector reviews break down which brands charge for which tier if you want the full picture.
One more honest point about app-based alerts: when the internet is down or the hub loses power, the local siren still sounds and only the remote notification stops. Test monthly, and treat the app as an addition to the alarm rather than a replacement for it.
Plan for the ten-year replacement
Smoke and CO alarms are consumable sensors, and both UL 217 and manufacturer guidance treat a decade as the service life. Sealed ten-year batteries are convenient but force a full unit replacement, while replaceable-battery models let you swap cells and keep the housing. Whichever route you take, mark the install date on the housing with a marker, because nobody remembers.
Consider a listener instead of a full swap
If your existing hardwired alarms already sound through the house properly and you only want phone alerts, a listener-style device that hears your existing siren and forwards it to an app or a smart speaker is far less work than a full replacement. We cover that approach in our connected smoke alarm guide, and it is also worth checking local fire code requirements before you rely on it as your primary protection.
Judge reliability by nuisance alarms, not by star rating
The real reliability question is not whether an alarm sounds during a fire, because every UL listed unit in this roundup will. The question is how often it sounds when there is no fire, because owners who get tired of false alarms eventually unplug the thing, and that is far more dangerous than a slightly slower notification.
Two patterns came out of the owner feedback we read. First, shower steam and cooking vapour are the two triggers that drive complaints, and photoelectric chambers with a humidity-tolerant design handle both better than cheaper single-beam units. Second, every connected model in this roundup needs a Wi-Fi reset after a router change, and several reviewers hit that at exactly the wrong moment. Set a calendar reminder for network maintenance days, and re-pair your alarms when your provider does upgrades.
Match the temperature range to where the alarm lives
Detectors have operating limits that matter more than most buyers expect. The Heiman CO units do not operate below 40 degrees Fahrenheit, which rules them out of an unheated garage, a cold cabin or a detached workshop. If your home has that kind of space, our CO detector picks for cabins and RVs cover models built for cold and off-grid locations.
Check humidity ratings too before you mount anything in a laundry room, a basement or a bathroom-adjacent hallway. The Kidde air quality monitor tolerates up to 95 percent relative humidity non-condensing, while some alarms in this class start reporting drift well before that.
How we evaluated these six units
We compared published specifications against owner feedback rather than lab teardowns, because the differences that matter to households show up in the reviews. For every product we checked the certification standard against the hazard it claims to detect, the power source and what happens during an outage, the interconnect method and range, and which app or hub the alerts depend on.
We also flagged the honest weaknesses in each section above rather than burying them, including the early battery reports on the Heiman smoke pack, the drifting environmental readings on the Kidde air quality unit, and the isolated failure-to-sound report on the plug-in Kidde CO detector. If a model has a documented flaw, you should hear it from us first.
Frequently Asked Questions
What is the best combination carbon monoxide and smoke detector?
The Kidde Smart Smoke and CO Detector RGCUDR-RW is the strongest combination unit here, because it senses both hazards in one case, sends smoke, CO and low-battery alerts to the Ring app with no subscription, and interconnects wirelessly so one alarm sounds the whole home. It runs on two included AA batteries, so it needs no wiring. If you also want air quality readings, the Kidde Smart CO and Indoor Air Quality Monitor adds TVOC and humidity tracking on top of electrochemical CO sensing.
Which smoke detector is the best for integrating with home assistant?
The Heiman C1-R Smart CO 3-Pack with Gateway is the clearest choice, because its published specifications list Home Assistant, IFTTT, Google Home and SmartThings support, and the gateway can also pair with Heiman smoke, leak and door sensors. Two practical notes: the gateway only connects on a 2.4 GHz Wi-Fi network and can be slow to pair, and the detectors stop working below 40 degrees Fahrenheit.
Is it worth getting a smart smoke detector?
Yes, mainly because of what happens when you are not there. A connected alarm pushes a phone notification the moment it detects smoke or carbon monoxide, tells you which hazard and which room, lets you test and silence it from the app, and can wake every other alarm in the house. The catch is that alerts depend on Wi-Fi, so the local siren must stay your primary layer and the app is an addition, not a replacement.
How many interconnected smoke detectors do I need?
NFPA 72 guidance calls for an alarm inside each bedroom, outside each sleeping area, on every level including the basement, and near sleeping areas such as hallways. That works out to roughly seven units for a two-bedroom single-storey home, nine or ten for a three-bedroom, and twelve or more for a four-bedroom across two floors. Keep units at least 10 feet from a cooking appliance to avoid nuisance alarms.
Do hardwired smoke detectors need to be replaced every 10 years?
Yes. Smoke and CO alarms contain sensors with a finite service life, and both UL 217 and manufacturer guidance treat about a decade as the end of that life even if the unit still chirps fine. Sealed ten-year battery models force you to replace the whole unit at that point, while models with replaceable batteries let you keep the housing. Mark the install date on each housing so you do not have to guess.
Conclusion: Which One Should You Buy
For most households, the Kidde Smart Smoke and CO Detector RGCUDR-RW is the pick to buy in 2026: dual-hazard detection, phone alerts with no subscription, wireless interconnect and AA power, all in one unit. Add the plug-in Kidde CO detector where a fuel-burning appliance lives, and cover the rest of the ceiling with photoelectric smoke alarms.
Go the eufy E10 route if you already run a HomeBase, choose the Heiman smoke pack if you want zero accounts and zero apps, and pick the Heiman CO gateway if Home Assistant is your automation platform. Whatever you install, test it monthly and replace the whole unit once its decade is done.