Smart home gadgets are often sold as tiny miracles: lights that obey your voice, thermostats that judge your sweater choices, and doorbells that turn every delivery into a nature documentary. Smart smoke and carbon monoxide detectors, however, are different. They are not novelty gadgets. They are life-safety devices first, and convenient connected devices second.
In 2024, the best smart smoke and carbon monoxide detectors combined reliable hazard detection with phone notifications, voice alerts, self-checks, and interconnected alarms. The result was a more useful warning system for people who travel, own rental properties, sleep through ordinary alarms, or simply want to know whether the “beep-beep-beep” is a dying battery or an actual emergency.
This guide focuses on three standout smart smoke and CO alarms that were strong choices in 2024: the Google Nest Protect, First Alert Onelink Safe & Sound, and X-Sense SC07-WX. Each takes a different approach to home safety, so the right choice depends on your wiring, smart-home platform, budget, and tolerance for being awakened by a ceiling-mounted Alexa.
Quick Comparison: The Top Smart Smoke and CO Detectors for 2024
| Detector | Best For | Standout Features | Main Drawback |
|---|---|---|---|
| Google Nest Protect, 2nd Gen | Best overall smart-home experience | Voice alerts, phone notifications, Pathlight, self-tests, smoke and CO detection | Premium price and ecosystem dependence |
| First Alert Onelink Safe & Sound | Best for Apple Home and Alexa households | Hardwired protection, Alexa speaker, AirPlay support, smart alerts | Requires hardwiring and costs more than a standard alarm |
| X-Sense SC07-WX | Best budget-friendly Wi-Fi option | App alerts, photoelectric smoke sensor, electrochemical CO sensor, replaceable battery | Fewer premium smart-home integrations |
What Makes a Smart Smoke and Carbon Monoxide Detector Worth Buying?
A regular smoke alarm can save lives. A smart smoke and carbon monoxide detector can add context, convenience, and remote awareness. The alarm still needs to make a loud noise in the home, because a phone notification is not especially useful if your phone is on silent, out of battery, or currently enjoying a vacation under the couch cushions.
The smartest models in 2024 did more than blast an 85-decibel siren. They could announce the location of smoke or carbon monoxide, alert household members through an app, send low-battery notices before the dreaded 2:13 a.m. chirp, and sometimes allow safe silencing of nuisance alarms when there was clearly no emergency.
Smart features should never replace the basics. A detector should be properly installed, tested monthly, replaced according to its manufacturer’s end-of-life instructions, and paired with a practiced household escape plan. Connected technology is a useful sidekick, not Batman.
1. Google Nest Protect, 2nd Generation: Best Overall Smart Smoke and CO Detector
The Google Nest Protect was one of the most polished smart smoke and carbon monoxide detectors available in 2024. It was not cheap, but it offered the kind of experience that made ordinary smoke alarms feel like they were designed by someone who had never burned toast.
Why the Nest Protect Stood Out
The Nest Protect combined smoke detection, carbon monoxide detection, Wi-Fi connectivity, voice guidance, app notifications, and automatic self-checks in one sleek device. Instead of jumping directly from silence to full panic mode, it could provide an early warning message, such as a notice that smoke was increasing in a specific room.
That room-specific voice alert was especially useful in larger homes. Hearing “There is smoke in the kitchen” is much more useful than hearing an alarm scream from an unknown hallway while everyone runs around asking, “Is it the oven? Is it the laundry room? Is somebody making popcorn again?”
The device used Google’s Split-Spectrum smoke-sensing technology, designed to identify a broader range of smoke particles than a traditional single-sensor photoelectric alarm. It also included a long-life electrochemical carbon monoxide sensor, helping it detect the invisible, odorless gas produced by malfunctioning furnaces, fireplaces, gas appliances, attached garages, and portable generators used incorrectly.
Best Features
- Smoke and carbon monoxide detection in one device.
- Voice alerts that identify the location of an issue.
- Smartphone notifications when you are away from home.
- Automatic safety checks and low-battery alerts.
- Pathlight feature that can provide a gentle nightlight in dark hallways.
- Battery-powered and hardwired versions for different home setups.
What to Consider Before Buying
The Nest Protect was a premium product, meaning outfitting an entire house could become expensive quickly. It also relied on a stable Wi-Fi connection and the Google/Nest ecosystem for its best smart features. It still sounded an alarm without Wi-Fi, but remote notifications and app controls depended on connectivity.
Independent testing also showed why buyers should never choose a detector based only on features. A smart detector may excel in some smoke and CO tests while performing differently in others. The important takeaway is simple: buy a properly certified alarm, install enough of them, and make sure every person in the home can hear them.
Best for: Homeowners who want polished app controls, clear voice alerts, smart-home integration, and a premium all-in-one safety device.
2. First Alert Onelink Safe & Sound: Best for Apple Home and Alexa Fans
The First Alert Onelink Safe & Sound took a delightfully unusual approach to home safety: it combined a smart smoke alarm, carbon monoxide detector, Alexa speaker, and connected home device in a single hardwired unit. It was essentially a smoke detector that also wanted to host a dinner party.
Why the Onelink Safe & Sound Was Different
Unlike basic smart alarms that simply send app notifications, the Onelink Safe & Sound included Amazon Alexa voice assistance and speaker functionality. In 2024, that made it appealing for homeowners who wanted a ceiling-mounted smart speaker in a kitchen, hallway, or living area without adding another countertop device.
The alarm used photoelectric smoke sensing and electrochemical carbon monoxide sensing. It could provide spoken location-based emergency notifications, app alerts, and loud in-home alarms. Because it was hardwired, it connected to household electrical power and included a long-life backup battery for outages.
Best Features
- Hardwired smoke and CO protection with battery backup.
- Integrated Amazon Alexa voice assistant.
- Smartphone alerts for smoke or carbon monoxide events.
- Voice guidance that can identify the affected location.
- Apple Home compatibility for households using Apple devices.
- Speaker features, including music playback and smart-home controls.
What to Consider Before Buying
The biggest limitation was installation. The Onelink Safe & Sound was designed for a hardwired electrical setup, so renters and homeowners without compatible junction boxes might need professional installation. It was also one of the more expensive smart smoke detectors in the category.
Its extra speaker and assistant features were fun, but buyers should not let the entertainment side distract from the safety side. A smoke alarm with Alexa is still a smoke alarm. The day it becomes most important is probably not the day you want to ask it for a weather forecast.
Best for: Apple Home users, Alexa households, and homeowners who already have hardwired alarms and want extra smart-home functionality in one device.
3. X-Sense SC07-WX: Best Budget Smart Smoke and CO Detector
The X-Sense SC07-WX offered a more affordable path into connected home safety. It was designed for buyers who wanted Wi-Fi alerts and app monitoring without paying premium smart-home prices for every alarm in the house.
Why the X-Sense SC07-WX Was a Smart Value Pick
The SC07-WX paired photoelectric smoke detection with electrochemical carbon monoxide sensing. It connected to a 2.4 GHz Wi-Fi network and sent app notifications for alarms, low batteries, and device status. This made it useful for people who travel often, manage a vacation home, or want a second set of eyes on a house while they are away.
Its replaceable CR123A battery made routine maintenance simpler than with some sealed-battery models, though that also meant owners needed to actually replace the battery when the app or alarm said it was time. Technology can send reminders, but it cannot currently climb a ladder and install the battery for you. Give it time.
Best Features
- Combined photoelectric smoke sensor and electrochemical CO sensor.
- Wi-Fi connectivity with smartphone notifications.
- Replaceable lithium battery.
- Large app-based monitoring system for multiple devices.
- Lower cost than many premium smart smoke alarms.
- Useful for rental homes, vacation properties, and budget-conscious households.
What to Consider Before Buying
The X-Sense SC07-WX did not offer the same polished smart-home integration as a Nest Protect or a full-featured Apple Home device. Buyers should also confirm the current certification labels, installation requirements, app compatibility, and interconnection behavior for the exact model being purchased.
That last detail matters. A Wi-Fi alarm can notify your phone, but whole-home safety is strongest when alarms are interconnected so one emergency triggers warnings throughout the house. Always verify that the alarms you buy can communicate with each other in the way your home needs.
Best for: Buyers who want app alerts and smoke/CO protection at a lower price, especially for apartments, vacation homes, or multi-device setups.
How to Choose the Right Smart Smoke and Carbon Monoxide Detector
Choose Safety Certification Before Smart Features
Start with the safety label, not the app screenshot. For a combination smoke and carbon monoxide detector, look for certification or listing information showing compliance with the appropriate smoke alarm and carbon monoxide alarm standards. In the United States, combination alarms should meet smoke and CO safety requirements, often referenced as UL 217 for smoke alarms and UL 2034 for carbon monoxide alarms.
In 2024, updated smoke alarm standards also placed stronger attention on reducing nuisance cooking alarms while maintaining effective fire detection. That is welcome news for anyone whose old detector treated pan-seared chicken like a five-alarm disaster.
Think About Power Source and Interconnection
Battery-powered smart alarms are easier to install and are especially practical for older homes, renters, and detached spaces. Hardwired detectors can be a better fit for homes with existing wired alarm systems, particularly when local building codes require them.
Interconnection is just as important as connectivity. When one alarm detects smoke or CO, interconnected alarms can sound throughout the home. That gives people sleeping upstairs, in a basement, or behind a closed door a better chance of hearing the warning.
Match the Detector to Your Smart-Home Platform
Google Home users may prefer a Nest-style ecosystem. Apple Home users may prioritize HomeKit-compatible products. Alexa households may enjoy integrated voice assistance. However, smart-home compatibility should be the tie-breaker, not the main reason to buy a life-safety device.
Know Where Alarms Should Go
Smoke alarms should generally be installed on every level of the home, inside bedrooms, and outside sleeping areas. Carbon monoxide alarms should be placed on every level of the home and near sleeping areas. Local rules vary, so always follow local code requirements and the manufacturer’s installation instructions.
Avoid placing smoke alarms directly next to cooking appliances, bathrooms, windows, air vents, or ceiling fans unless the manufacturer specifically allows it. Poor placement can lead to nuisance alarms, and nuisance alarms are dangerous because frustrated people sometimes disable them. A disabled smoke alarm is just a small plastic frisbee with trust issues.
Smart Detector Safety Rules You Should Never Ignore
- Test each smoke and CO alarm monthly using its test button.
- Replace the entire alarm at the end of its rated service life.
- Do not paint over alarms or cover vents with dust, tape, or decorations.
- Replace batteries promptly when the device signals a low-battery warning.
- Make a household escape plan and practice it with children and guests.
- When a smoke alarm sounds, leave the home immediately and call 911 from a safe location.
- When a carbon monoxide alarm sounds, move to fresh air immediately and contact emergency services or local authorities.
Real-World Experiences With Smart Smoke and Carbon Monoxide Detectors
Living with a smart smoke and carbon monoxide detector is usually less dramatic than people expect, which is exactly the point. In normal daily life, the best experience is mostly invisible: the app quietly confirms that everything is working, the device runs a self-check, and nobody has to stand on a kitchen chair at midnight trying to identify which alarm has started chirping like an angry electronic cricket.
The first experience that tends to win people over is the low-battery notification. Traditional alarms have a special talent for announcing a weak battery at the least convenient moment possible. They somehow sense that you have an early flight, a newborn baby, or a deep emotional commitment to sleeping past 3 a.m. Smart alarms can send a notification before the battery becomes a full-blown household mystery. That does not remove maintenance, but it makes maintenance more civilized.
Another useful experience comes when someone is away from home. Imagine you are at work, visiting family, or halfway through a grocery run when your phone reports smoke in the kitchen. A smart detector does not replace emergency services, but it can give you a chance to call a neighbor, contact a family member, or call 911 much faster than you would with a traditional alarm that only screams into an empty house.
Voice alerts are also more helpful than they sound on paper. A standard alarm creates urgency but not much information. A smart smoke detector that announces the room can reduce confusion during a stressful moment. In a multi-level home, knowing that the warning is in the basement, garage, hallway, or kitchen can help everyone move toward the safest exit instead of gathering in one room to debate whether dinner has become “a little smoky.”
Of course, smart detectors can create a few frustrations. Wi-Fi setup may be annoying in homes with mesh networks, separate 2.4 GHz and 5 GHz bands, or routers that seem to require a graduate degree in networking. Phone permissions can also cause trouble. If notifications are disabled, a smart alarm may be perfectly connected while your phone remains blissfully unaware of it.
Then there are nuisance alarms. Even better sensors can be challenged by steam, broiling, frying, aerosols, or a kitchen experiment involving too much oil and too little patience. The advantage of a smart detector is that it can often send an early alert, identify the location, and let you check the situation without immediately assuming the house has become a disaster movie set.
The most important real-world lesson is that a smart alarm should make safety easier, not make homeowners overconfident. The app is helpful. The voice alert is helpful. The remote notification is helpful. But the winning combination is still simple: enough working alarms, correct placement, regular testing, fresh batteries when needed, and a fast exit plan that every person in the home understands.
Final Thoughts
The best smart smoke and carbon monoxide detectors for 2024 were not necessarily the ones with the flashiest apps or the fanciest speakers. The winning models were the ones that paired strong smoke and CO detection with clear alerts, dependable power, reliable interconnection, and useful remote notifications.
The Google Nest Protect was the strongest all-around smart option, the First Alert Onelink Safe & Sound was ideal for hardwired Alexa and Apple Home households, and the X-Sense SC07-WX offered a practical budget-friendly Wi-Fi alternative. Pick the model that fits your home, then install enough alarms to protect every sleeping area and every level of the building. Smart home safety is not glamorous, but neither is explaining to the fire department why your smoke detector was disconnected because it once objected to bacon.
