Best Smart Smoke and Carbon Monoxide Detectors

This guide compares the leading smart smoke and CO detectors for U.S. homes and explains which type is best for different situations, including Google Home, Ring, Apple Home, renters, large homes, and homeowners who want to avoid monthly fees.

Best Smart Smoke and CO Detectors at a Glance

1. First Alert SC5 Smart Smoke and Carbon Monoxide Alarm

Best for: Google Home users

The First Alert SC5 is one of the most important options for homeowners looking for a modern smart replacement for older connected smoke alarms. It combines smoke and carbon monoxide detection with connected notifications and integration into the Google smart-home ecosystem.

The SC5 is particularly attractive for households already using Google Home because connected alarms are most useful when they fit naturally into the smart-home system you already use.

Pros

• Smoke and carbon monoxide detection in one device
• Smartphone notifications
• Designed for integration with the Google ecosystem
• Available in configurations suitable for hardwired installations
• Useful for homeowners replacing older interconnected alarms

Cons

• More expensive than conventional smoke/CO alarms
• Smart features can make setup more complicated
• Hardwired models may require electrical work
• Availability and model options can vary

Recent 2026 comparisons identify the SC5 as a major successor option in the post-Nest Protect smart-alarm market. Current 2026 comparisons

2. Kidde Smart Smoke and Carbon Monoxide Detector

Best for: Ring and Alexa households

Kidde’s smart combination alarms are a strong choice for homeowners who already use Amazon’s Ring ecosystem. The detector combines smoke and CO detection with connected notifications, allowing an alarm event to be communicated through compatible smart-home services.

Kidde also has a large range of conventional and interconnected smoke and CO alarms, which can make it easier to build a compatible system when replacing multiple detectors throughout a house.

Pros

• Smoke and CO detection
• Smartphone alerts
• Useful for Ring/Alexa households
• Available in different installation configurations
• Established smoke-alarm manufacturer

Cons

• Some models have lower user ratings than competing products
• Compatibility depends on the specific model
• Smart-home features vary between versions

Consumer Reports’ 2026 testing includes several Kidde combination alarms among its evaluated models, including smart and conventional options. Consumer Reports testing

3. First Alert Onelink Safe & Sound

Best for: Alexa and Apple Home users

The First Alert Onelink Safe & Sound takes a different approach by combining smoke and CO detection with a built-in smart speaker. This makes it more than just an alarm, although the additional speaker hardware also increases the price.

For households already invested in Alexa or compatible Apple smart-home products, the Onelink can provide a convenient combination of safety and smart-home functionality.

Pros

• Smoke and CO detection
• Built-in smart speaker
• Alexa functionality
• Smartphone notifications
• Useful for connected-home users

Cons

• More expensive than basic combination alarms
• Additional smart-speaker features are unnecessary for some homeowners
• Installation may be less flexible than battery-powered alternatives

4. X-Sense Smart Smoke and CO Alarms

Best for: Budget-conscious smart-home buyers

X-Sense offers connected smoke and CO alarms aimed at homeowners who want smartphone notifications without paying premium prices for the best-known smart-alarm brands.

Different X-Sense models use different combinations of sensors and connectivity, so buyers should check the exact model rather than assuming that every X-Sense detector provides identical features.

Pros

• Generally lower cost than premium smart alarms
• Smartphone notifications on compatible models
• Smoke and CO combination models available
• Sealed-battery options are available

Cons

• Model lineup can be confusing
• Smart-home compatibility varies
• Some models require a separate hub or gateway

5. Kidde RemoteLync Monitor

Best for: Homeowners who already have working smoke alarms

A smart detector is not always the only way to make a home’s existing alarms connected. A monitoring device can listen for an existing alarm and send a notification when it detects the alarm sound.

This approach can be attractive when a homeowner has several relatively new conventional detectors and does not want to replace all of them simply to obtain smartphone notifications.

Pros

• Can reduce the need to replace every existing alarm
• Useful for retrofitting an existing system
• Can provide remote notifications
• Potentially lower installation cost

Cons

• It does not replace the underlying smoke/CO sensors
• Performance depends on the existing alarms
• Does not provide the same capabilities as an integrated smart detector

Smart Smoke and CO Detector Comparison

What to Look for in a Smart Smoke and CO Detector

1. Smoke Sensor Technology

Do not choose an alarm solely because it has Wi-Fi. The smoke-sensing technology is more important.

Photoelectric sensors are generally strong at detecting slow, smoldering fires, while ionization technology has historically been associated with faster-flaming fires. Some modern alarms use more sophisticated sensing approaches to improve detection across different fire types.

Smart connectivity does not compensate for inadequate smoke detection. WIRED’s 2026 discussion of smart smoke alarms similarly emphasizes that sensor technology and correct placement are more important than connected features. WIRED’s smart smoke alarm analysis

2. Carbon Monoxide Sensor

For a combination detector, look for a dedicated CO sensor rather than assuming that a smoke detector can detect carbon monoxide. Electrochemical CO sensors are commonly used in residential CO alarms.

A CO alarm is especially important in homes with fuel-burning appliances, fireplaces, furnaces, boilers, attached garages, or other potential sources of carbon monoxide.

3. Safety Certification

Look for appropriate U.S. safety certification and compliance markings for the exact model being purchased. For smoke alarms, UL 217 is an important standard to check. For CO alarms, the applicable certification should also be verified.

Do not assume that a product described as “smart” or “Wi-Fi” is automatically a properly certified life-safety alarm.

4. Smartphone Alerts

The biggest advantage of a connected detector is the ability to receive an alert when you are away from home.

A useful system should clearly communicate:

• Which detector triggered
• Whether the event is smoke or CO
• Whether the alarm has stopped
• Low-battery or fault conditions
• Connectivity problems when applicable

5. Voice Alerts

Voice alerts can be particularly useful in larger houses. Instead of simply hearing a siren, occupants may receive information identifying the room or type of emergency.

This can reduce the time required to determine where the problem is located.

6. Wireless Interconnection

Interconnected alarms are valuable because one alarm can cause other alarms throughout the house to sound. This is especially useful in multistory homes where a detector in a basement or garage-adjacent area may not be immediately audible in a bedroom.

Check whether the exact model supports wireless interconnection. Wi-Fi connectivity and alarm interconnection are not necessarily the same thing.

7. Battery Life

Battery-powered smart detectors are convenient for renters and existing homes without suitable wiring. Sealed 10-year battery models can reduce routine battery replacement.

Hardwired alarms can be preferable when compatible wiring already exists, particularly in homes with interconnected detectors.

Best Smart Smoke and CO Detector by Use Case

Smart Smoke Detector vs. Regular Smoke Detector

Do Smart Smoke Detectors Need Wi-Fi?

The detector can normally continue performing its basic local alarm function even if the home’s internet connection is unavailable, depending on the model. However, remote smartphone notifications generally require the detector’s communication system and cloud/app service to be functioning.

This distinction is important: Wi-Fi should be treated as an additional notification feature, not as the primary safety mechanism.

Do Smart Smoke and CO Detectors Require a Monthly Fee?

Many smart smoke and CO detectors provide basic smartphone alerts without a monthly subscription. However, subscription requirements vary if the product is connected to a broader professionally monitored security system.

Before purchasing, check whether the advertised feature is included without a subscription. A detector may provide free alarm notifications while optional professional monitoring requires a recurring fee.

Are Smart Smoke Detectors Worth It?

For many homeowners, yes. The biggest advantage is remote notification. A conventional detector can warn someone who is nearby, while a smart detector can potentially notify you when you are at work, traveling, or otherwise away from home.

Smart detectors are particularly useful when:

• The house is frequently unoccupied
• You have multiple floors
• You want room-specific notifications
• You already use a compatible smart-home ecosystem
• You manage a rental property or second home
• You want to monitor detector status remotely

However, spending more on smart features is not necessarily worthwhile if it means installing fewer detectors or delaying replacement of old alarms.

How Many Smoke and CO Detectors Do You Need?

The correct number depends on the home’s layout and applicable local building and fire-safety requirements. Smoke alarms are generally needed inside bedrooms, outside sleeping areas, and on every level of a home. Additional alarms may be appropriate depending on the home’s configuration.

CO alarm placement depends on the home’s fuel-burning appliances and applicable requirements. Always follow the detector manufacturer’s installation instructions and local code.

Where Should Smart Smoke and CO Detectors Be Installed?

• Inside bedrooms where required by applicable codes
• Outside sleeping areas
• On each level of the home
• Near sleeping areas where recommended
• In locations specified by the manufacturer’s instructions

Avoid installing smoke detectors directly next to cooking appliances or in locations where normal steam can cause nuisance alarms. CO detector placement should follow the manufacturer’s instructions and local requirements.

What About the Google Nest Protect?

The Google Nest Protect remains important when discussing smart smoke and CO detectors because it established many of the features consumers now expect, including voice alerts, room identification, self-testing, wireless interconnection, and smartphone notifications.

However, buyers should be careful when shopping for one in 2026 because product availability and Google’s current hardware strategy have changed. Some 2026 sources report that Google discontinued Nest Protect production and that remaining units are being sold through existing inventory. 2026 market analysis

For that reason, shoppers should consider current replacement products rather than automatically choosing an older Nest Protect simply because it was historically one of the best-known smart alarms.

How We Would Choose

For a Google-oriented smart home: Start with the First Alert SC5 or another current First Alert model specifically compatible with your Google Home setup.

For a Ring/Alexa home: A compatible Kidde Smart smoke and CO alarm is worth considering because of its ecosystem integration.

For Apple-oriented homes: Check current First Alert Onelink compatibility before purchasing, particularly if HomeKit integration is important.

For renters: Choose a battery-powered combination smoke/CO alarm with app notifications and avoid models that require hardwiring unless the landlord permits installation.

For the lowest overall cost: A high-quality conventional smoke/CO alarm may be a better safety investment than buying fewer expensive smart detectors.

Frequently Asked Questions

Can a smart smoke detector detect carbon monoxide?

Only combination models can detect both smoke and carbon monoxide. A smart smoke-only detector does not automatically detect CO.

Will a smart smoke detector work without internet?

Most properly designed alarms continue to provide their local audible alarm when internet service is unavailable. Remote app notifications, however, generally depend on connectivity.

Are smart smoke detectors safer than regular smoke detectors?

Not necessarily. The core detection technology and correct installation are more important than connectivity. Smart features primarily improve notification, monitoring, and convenience.

Do smart smoke detectors detect fires faster?

Smart connectivity itself does not make smoke detection faster. Detection performance depends on the sensor technology and alarm design.

Can a smart detector replace a carbon monoxide detector?

A combination smoke and CO alarm can provide both functions. A smoke-only smart detector cannot replace a dedicated CO alarm.

Do smart smoke detectors need batteries?

Some models are battery-powered, while others are hardwired with battery backup. Sealed 10-year battery models are also available.

Can smart smoke detectors be interconnected?

Some models support wireless or wired alarm interconnection. Do not assume that Wi-Fi connectivity means that all alarms will automatically sound together; check the exact model’s specifications.

Final Verdict

The best smart smoke and carbon monoxide detector is not necessarily the one with the most smart-home features. The priority should be reliable smoke detection, dependable CO detection, appropriate certification, audible alarms, suitable placement, and a reliable power source. Smart connectivity should come afterward.

For a modern connected home, the First Alert SC5 is a strong option for Google-oriented households, while Kidde Smart models are particularly attractive to Ring and Alexa users. First Alert Onelink is worth considering when Alexa or Apple Home integration is important, while X-Sense offers lower-cost connected alternatives.

Whichever model you choose, do not reduce the number of required alarms simply to afford smart features. A properly installed, certified conventional detector is more valuable than an expensive smart detector that is missing from a critical location.

Safety note: Always follow the manufacturer’s installation, testing, replacement, and maintenance instructions and applicable local fire and building codes. Smoke and carbon monoxide alarms are life-safety devices and should not be selected solely on price, app ratings, or smart-home compatibility.

Sources and Further Reading

• Consumer Reports: Best Smoke and Carbon Monoxide Detectors of 2026
• WIRED: Should Smoke Alarms Be Smart?
• 2026 Smart Smoke and CO Detector Market Comparison