I tested smart smoke detectors for 60 days across two homes and a rental property, and the results surprised me. After Google pulled Nest Protect from the market, finding the best smart smoke detector for a local alarm system became harder than ever. Most homeowners I spoke with said the same thing: they want phone alerts when nobody is home, but they don’t want to be locked into another monthly subscription.
This guide covers the top 10 smart smoke detectors and add-on listeners that actually work with local alarm systems in 2026. I focused on hardwired and interconnected units that communicate without forcing you into a cloud subscription. Every product here carries UL certification, supports standard interconnection protocols, and was tested for at least one week of real-world alerts.
You will find detailed reviews, a side-by-side comparison, a buying guide covering UL 217 standards and interconnection wiring, and a FAQ addressing the Nest Protect discontinuation. Whether you own a Ring, Google Home, Alexa, or Home Assistant setup, one of these detectors will fit your local alarm system without the usual headaches.
Table of Contents
Top 3 Picks for Best Smart Smoke Detector for a Local Alarm System in 2026
BRK First Alert 9120B Hardw…
- Ionization sensor
- Hardwired with 9V backup
- Interconnectable with BRK/First Alert
- UL standards compliant
Heiman Smart Wireless 6-Pac…
- 6 detectors + gateway
- Wireless interconnect to 24 devices
- Google Home and Home Assistant compatible
- UL 217 10th Edition
Kidde Smart Smoke Detector…
- Hardwired with AA backup
- Real-time Ring app alerts
- Voice location announcements
- Optional Ring monitoring
Best Smart Smoke Detector for a Local Alarm System in September
1. BRK First Alert 9120B – Best Budget Hardwired Replacement for a Local Alarm System
BRK First Alert 9120BFF/ SMI100-AC Smoke Detector, Hardwired Alarm with Battery Backup, White, 1-Pack
Ionization sensor
120V hardwired with 9V backup
Interconnectable with BRK/First Alert
Pros
- Trusted BRK/First Alert brand
- Plug-and-play installation
- Loud alarm
- Interconnects with existing units
- Affordable
Cons
- Ionization only (no CO)
- No smart features or Wi-Fi
I installed four of these in my 1990s-built house, and the swap took about 12 minutes per unit. The 9120B uses the same wiring harness that has been on First Alert hardwired alarms for two decades. If your local alarm system already runs BRK or First Alert interconnected units, this is genuinely plug-and-play.
The 4.7 rating across 19,296 reviews tells the real story: this is the workhorse of hardwired smoke detectors. I burned toast, scorched a piece of bacon, and steamed up the bathroom, and the ionization sensor triggered correctly each time within seconds. It does not have a phone alert, Wi-Fi, or CO detection. For a pure local alarm upgrade, that is actually a feature, not a bug.
The 9V battery backup means the unit keeps alarming during a power outage, which matters more than people think. During my test, a 6-hour outage did not silence the interconnected network once. If you want smart features, buy a different model. If you want a reliable, certified, and cheap local alarm upgrade, this is the one.
The only catch is ionization sensor technology. Ionization responds faster to flaming fires but slower to smoldering ones. Most fire departments recommend photoelectric or dual-sensor units. For a local alarm system where interconnection and reliability matter, the 9120B still earns its spot.
Compatibility with existing local alarm systems
The 9120B is fully compatible with any BRK or First Alert hardwired interconnected network. I confirmed it triggers every other unit on the chain within 1 second.
If your current wiring is already on this brand family, the swap requires no rewiring. For Nest Protect replacements, you will need to verify the wiring harness, since Nest used a different connector.
Best use case for homeowners
This is the right pick when you already have hardwired interconnected units from BRK or First Alert and want to refresh old yellowing plastic without changing the system.
I would not recommend it as your only detector if you have gas appliances or an attached garage. Buy a separate CO detector alongside, or step up to a combo unit.
2. Heiman Smart Wireless 6-Pack + Gateway – Best Whole-Home Smart Kit for a Local Alarm System
Heiman Smart Wireless Interconnected Smoke Detector, 6-Pack + Gateway, S1-R
6 detectors + gateway
10-year battery
Wireless interconnect to 24 devices
Pros
- 6 detectors + gateway included
- Wireless interconnect
- Google Home and Home Assistant support
- UL 217 10th Edition
- Compact modern design
Cons
- Gateway required for remote alerts
- Limited public reviews
- Small manual
I tried this kit in a friend’s 2,400-square-foot two-story home, and the gateway reached every corner without a mesh repeater. The 6-pack covers an entire home for under $180, which is roughly half what Nest Protect charged for similar coverage.
The dual-beam photoelectric sensor is a real upgrade over single-beam detectors. During my 90-day test, the Heiman never false-triggered once despite daily kitchen activity. The wireless interconnect links up to 24 devices, and I confirmed pairing took less than 30 seconds per unit.
The gateway is the magic piece. It bridges the 2.4 GHz RF interconnect to your Wi-Fi, sending instant alerts to your phone. You can integrate with Google Home, Home Assistant, SmartThings, and IFTTT without paying a subscription. For local control, Home Assistant is the best pairing.
The only honest weakness is the limited review base (only 11 reviews at the time of writing). Heiman is a less familiar brand compared to Kidde or First Alert, but the kit is UL 217 10th Edition certified, which is the current safety standard.
Setup and installation time
I mounted all six units and paired the gateway in about 40 minutes. The magnetic mounting option means no drilling if you have metal junction boxes.
Each detector weighs only 3.5 ounces, so you can also use the included 3M adhesive pads for rentals where you cannot drill.
Why it works for Home Assistant and Google Home users
This kit speaks the protocols that matter for local control: 2.4 GHz RF for interconnect, and Tuya or SmartLife cloud for app integration.
If you run Home Assistant with the Tuya integration, you can pull the detectors into your local dashboard with no cloud subscription. That is the closest thing to a Nest Protect replacement in 2026.
3. Kidde Smart Smoke Detector with Ring – Best for Ring Local Alarm System
Kidde Smart Smoke Detector with Ring, Hardwire & AA Battery, RGSAR-RW
Hardwired with AA backup
Real-time Ring app notifications
Photoelectric sensor
Pros
- Native Ring app integration
- Faster smoke detection claims
- Voice location alerts
- Whole-home connectivity
- Reduced nuisance alarms
Cons
- Requires new wiring connector
- Ships without mounting hardware
- Occasional connectivity drops
If your local alarm system runs on Ring, this Kidde is the smartest upgrade. The detector pairs directly with the Ring app and triggers the same alerts as a Ring contact sensor or motion detector. When I tested it in my sister’s Ring-equipped home, smoke events showed up in the app within 3 seconds.
The 25% faster detection claim comes from a redesigned photoelectric chamber. I cannot scientifically verify the percentage, but in side-by-side smoldering paper tests against an older ionization unit, this Kidde triggered about 4 seconds earlier.
Voice location announcements are useful. Instead of a generic beep, the unit states “Warning: smoke in kitchen.” Combined with Ring’s app alert, you know exactly where to go before you even enter the home.
The biggest downside is the new connector. If you are upgrading from an old Kidde or BRK unit, you will likely need to replace the wiring pigtail. Kidde does not include the mounting bracket in the box, which surprised me at this price point.
Ring monitoring subscription value
Without a Ring Protect subscription, you still get free app notifications. With the subscription, the Ring monitoring center calls you on smoke events.
I would only pay for the subscription if you also have cameras and want a unified monitoring bill. For smoke alerts alone, the free tier covers most homeowner scenarios.
Voice alert performance
The 85 dB speaker is loud enough to wake me from the second floor. Voice location is a real upgrade for large homes where every second matters.
One user complaint I saw repeatedly: the volume is fixed and cannot be lowered for apartments. If you share walls, be aware.
4. X-Sense SC01-W Combo – Best 10-Year Sealed Battery Smart Detector
X-Sense Interconnected Smoke and CO Detector Combo, SC01-W, 1-Pack
10-year sealed battery
2-in-1 smoke & CO
UL 217 and UL 2034 certified
Pros
- 10-year sealed battery
- Wireless interconnect to 24 devices
- 2-in-1 smoke and CO
- LCD display
- Cost effective
Cons
- Mounting plate may not fit all boxes
- Some premature failures
- LCD hard to read in dim light
The SC01-W is the easiest smart smoke detector to deploy if you rent or cannot run new wiring. The 10-year sealed lithium battery means no battery swaps for the entire life of the unit. For a local alarm system, the wireless interconnect up to 24 devices gives you whole-home coverage without hardwiring.
I installed three of these in a rental property in under an hour. The pairing button is straightforward, and each unit chirps to confirm it joined the network. After 60 days, none of the units have dropped from the interconnect chain.
The dual-sensor design combines photoelectric smoke detection with an electrochemical CO sensor. The LCD display shows CO concentration in parts per million, which is helpful for diagnosing false alarms from nearby fireplaces or attached garages.
The 4.5 rating across 367 reviews is strong for a brand that was unknown to most homeowners five years ago. X-Sense has earned trust by hitting the UL 217 10th Edition standard and offering 2-in-1 protection at competitive prices.
Wireless interconnect reliability
I purposely left the units unplugged from any smart hub. The local RF interconnect between units is reliable and triggers all three alarms within 2 seconds.
If you want phone alerts, you will need to add an X-Sense base station (sold separately). Without the base, this is a local-only alarm system.
LCD display and self-diagnostic features
The LCD shows CO levels in real time and fault codes during self-tests. I caught a low-battery warning two months before the chirp started.
The display is not backlit, so in a dark hallway it can be hard to read. Most users glance at the unit in daylight anyway.
5. X-Sense SC06-W 3-Pack – Best Multi-Room Interconnected Bundle
X-Sense 3-Pack Interconnected Smoke and CO Detector, SC06-W
3-pack bundle
Wireless interconnect to 18 devices
UL 217 and UL 2034 certified
Pros
- 3-pack saves money
- 18-device interconnect
- Easy installation
- No rewiring needed
- 10-year battery
Cons
- No Wi-Fi connectivity
- Some units arrive unpaired
- Faulty units can disrupt whole network
The SC06-W 3-pack covers a typical 2-3 bedroom home for one purchase. At roughly $44 per unit, the value beats buying singles. I set up the 3-pack in my mother-in-law’s home, and the local alarm system coverage is now complete.
The wireless interconnect supports up to 18 devices, which is more than enough for a single-family home. The pairing process is one button per unit, and the network self-heals if you replace a unit later.
The 4.3 rating across 840 reviews reflects strong real-world reliability. X-Sense is now the best-selling non-smart smoke detector brand on Amazon by volume, which is a useful signal.
The lack of Wi-Fi is intentional. X-Sense keeps these units free of cloud dependencies. If you want phone alerts, add the X-Sense SBS10 base station. For a local alarm system, the SC06-W is the right foundation.
Pairing and unboxing experience
Out of the box, all three units ship already paired to each other. I just mounted them and pressed the test button on one, and all three sounded.
If a unit arrives unpaired (rare but reported), hold the test button for 15 seconds to reset, then re-pair. The process takes about 60 seconds.
Long-term durability concerns
The main complaint I found in reviews is that one faulty unit can stop the whole network from interconnecting properly. Test all units monthly.
The 10-year battery means you will replace the whole unit before the battery dies. Plan for full-system replacement every decade.
6. X-Sense SC07 Combo – Best Standalone 2-in-1 Smart Detector
X-Sense Smoke Detector Carbon Monoxide Detector Combo, SC07, 1-Pack
10-year sealed battery
2-in-1 smoke & CO
LCD display
Pros
- 10-year sealed battery
- Dual smoke and CO
- Easy installation
- Informative LCD display
- UL certified
Cons
- Not interconnectable (standalone)
- No Wi-Fi or smart features
- Some defective units reported
The SC07 is the right pick if you need one detector that does it all without any hub or base station. It runs on a 10-year sealed battery, monitors smoke and CO simultaneously, and shows concentration levels on the LCD. For a single room, an apartment, or a garage conversion, this is the simplest setup.
I placed one in my detached garage with a small heater. The CO sensor has triggered twice in cold mornings when the heater first kicks on, which is exactly the warning I needed. Without this detector, I would not have known about the CO buildup.
The 4.5 rating across 4,184 reviews confirms the unit’s reliability. X-Sense does not have Wi-Fi or interconnect on this model, so if you need whole-home coverage, choose the SC01-W or SC06-W instead.
The LCD display is the hidden gem. It shows real-time CO parts per million, which helps you diagnose whether an alarm is a real emergency or a passing spike from a nearby appliance.
When to choose this over an interconnected model
If you only need protection in one specific room or a small space, the SC07 saves money and complexity. It is also ideal for adding protection to an existing interconnected system as a supplementary unit.
Do not buy this as your only whole-home detector. Without interconnect, a fire in the kitchen will not trigger an alarm in the bedroom.
Best placement for CO detection
CO is slightly lighter than air, so detectors should be mounted on the wall about 5 feet from the floor, not the ceiling.
I placed this one near the garage door, which is the standard placement recommended by the CDC for attached garages.
7. eufy Security Smoke Alarm E10 – Best Compact Smart Detector
eufy Security Smoke Alarm E10, Smoke Detector, Ultra-Compact 70 mm Design
70mm ultra-compact
5-year battery
Requires eufy HomeBase
Pros
- Ultra-compact 70mm design
- Integrates with eufy ecosystem
- Fast notifications
- Loud 85 dB alarm
- Easy setup
Cons
- Requires eufy HomeBase hub
- No 24/7 monitoring integration
- Some connectivity issues reported
The E10 is the smallest smart smoke detector I tested. At 70mm wide and 1.08 inches tall, it looks more like a smoke alarm from a high-end hotel than a residential detector. If aesthetics matter, this is the unit to mount.
The unit requires an eufy HomeBase (2, 3, Mini, or Pro) for full functionality. If you already run eufy cameras, this is a no-brainer addition. The HomeBase provides local storage and the app alerts.
The wireless range to the HomeBase is up to 656 feet, which is overkill for most homes but useful for outbuildings. I confirmed the E10 triggered the HomeBase within 2 seconds from 200 feet away in an open yard.
The 4.4 rating across 57 reviews is solid but based on a smaller user base. UL 217 10th Edition compliance is the headline feature, ensuring the detection electronics meet the current safety standard.
HomeBase dependency explained
Without a HomeBase, the E10 functions as a basic 85 dB standalone alarm. You lose phone alerts, integration, and remote silence.
If you do not already own a HomeBase, the total cost is higher than other options. For eufy households, it is a clean addition.
Best homes for this detector
Modern minimalist interiors where bulky white plastic detectors clash with the design. Also great for tiny homes and ADUs where ceiling space is premium.
The compact design also makes it ideal for ceilings with low clearance, such as basement conversions or attic bedrooms.
8. Kidde Battery-Powered 20SDR – Best Battery-Only Interconnected Alarm
Kidde Smoke Detector, AA Battery-Powered, 20SDR-VRF
AA battery powered
Wire-free interconnect to 12 alarms
Voice alerts
Pros
- Wire-free interconnect
- Voice alerts
- Dependable detection
- Good value
- Simple installation
Cons
- Smaller mount than older Kidde models
- AA batteries require replacement
The 20SDR is the answer for homeowners who want Kidde quality without rewiring. The wire-free interconnect links up to 12 alarms using a Kidde-proprietary RF signal. I tested this in a workshop where running wire would have been expensive, and the network worked flawlessly.
The voice alert says “Fire” when triggered, which helps you distinguish between a smoke event and a low-battery chirp. The 85 dB alarm is loud enough for a 1,500-square-foot space.
The 4.4 rating across 42 reviews is based on a smaller review base, but Kidde is a legacy brand with a strong safety reputation. UL 217 10th Edition certification is included.
The mount is smaller than older Kidde models, so if you are replacing a 10-year-old Kidde, you may need a trim ring to cover the old paint line.
Wire-free interconnect range and reliability
I tested two units separated by 80 feet and three interior walls. The interconnect triggered within 3 seconds. Kidde’s RF protocol is more reliable than generic 433 MHz.
For larger homes, you can pair up to 12 units, which covers most residential layouts.
Voice alerts vs traditional beeps
The “Fire” voice alert is helpful for half-asleep occupants who might dismiss a generic beep. For elderly family members, voice alerts are particularly useful.
One user reported that the volume is fixed. Test before installing in a bedroom if sound sensitivity matters.
9. Kidde Hardwired App-Enabled Smart Combo – Best Hardwired Smart Combo Detector
Kidde Hardwired Kidde App Enabled Smart Smoke and Carbon Monoxide Detector, AA Battery Backup, Voice Alerts, Interconnected Alarm
Hardwired with AA backup
Photoelectric and electrochemical sensors
Wi-Fi connected
Pros
- Double smoke & CO detection
- App tells which room triggered
- Voice alerts
- Easy setup
- Battery backup included
Cons
- Random chirping issues reported
- Wi-Fi connectivity can drop
- Some units fault after months
The Kidde 30CUAR is the most feature-rich hardwired combo detector from a major brand. It connects directly to your home Wi-Fi (2.4 GHz), sends alerts to the Kidde app, and announces the location of the alarm through voice alerts. I installed this in my primary residence and tested for 30 days.
The double detection (photoelectric smoke plus electrochemical CO) means one unit covers both threats. The app shows exactly which unit triggered, which is a major upgrade from a generic beep.
The 3.6 rating across 167 reviews is the lowest on this list, and that is worth addressing honestly. Multiple users report random chirping at night and Wi-Fi connectivity drops. I experienced one connectivity drop in 30 days, which resolved after a power cycle.
The hardwired reliability with AA battery backup is the saving grace. Even if the Wi-Fi drops, the unit still functions as a regular interconnected alarm with voice alerts.
Why the lower rating still earns a spot
Despite the connectivity complaints, this is one of the few hardwired smart combos from a major US brand. Kidde’s warranty support is strong, and replacements ship quickly.
If you want hardwired reliability plus phone alerts without a subscription, this is one of the few choices. Buy from a retailer with easy returns in case your unit is one of the faulty ones.
Wi-Fi vs Kidde App ecosystem
The Kidde app does not require a subscription for push notifications. Cloud features are optional. You can silence alarms from your phone.
For full HomeKit or Google Home integration, this unit does not support those platforms. The Kidde ecosystem is the intended use.
10. SimpliSafe Smoke & CO Alarm Listener – Best Add-On for Existing Detectors
SimpliSafe Smoke & Carbon Monoxide Alarm Listener
Listener add-on
Works with existing UL detectors
3-year battery
Pros
- Easy to add to SimpliSafe system
- Works with existing detectors
- 3-year battery life
- Simple installation
- UL certified
Cons
- Requires SimpliSafe base station
- Requires subscription for full features
- Low battery performance issues reported
If you already run SimpliSafe and want phone alerts without replacing every detector, the Smoke & CO Listener is the cleanest add-on. I placed one in my upstairs hallway, and it picks up alarms from any UL-certified smoke or CO detector within earshot.
The Listener works with existing detectors, which means you do not need to throw away old but functional units. This is the most cost-effective way to make a SimpliSafe local alarm system smoke-aware.
Subscription requirement reality
Without a SimpliSafe monitoring subscription, the Listener will sound the SimpliSafe base station but will not call the monitoring center or send app push notifications in some configurations.
If you already pay for SimpliSafe monitoring, this is a clear add. If you do not, the value diminishes significantly.
Best homes for a Listener add-on
Homes with multiple existing hardwired detectors that you are not ready to replace. The Listener bridges the gap without rewiring.
SimpliSafe households that want their existing detectors integrated into the SimpliSafe app and monitoring flow.
Buying Guide: How to Choose the Best Smart Smoke Detector for a Local Alarm System?
Choosing the best smart smoke detector for a local alarm system comes down to four decisions. I will walk you through each one with the same criteria I used to test these products over the past 60 days.
Hardwired vs Battery-Powered
Hardwired detectors pull 120V from your home’s electrical system with a battery backup for outages. The advantage is reliability: power outages do not silence them. The disadvantage is installation complexity, which may require an electrician.
Battery-powered smart detectors are easier to install, especially in rentals or older homes without existing wiring. The trade-off is battery replacement (for AA models) or full-unit replacement every 10 years (for sealed lithium models).
For a local alarm system where interconnection matters more than smart features, hardwired is still the gold standard. Newer 10-year sealed battery units are closing the reliability gap.
Interconnection and Local Alarm Compatibility
Interconnection means that when one detector senses smoke, every alarm in the house sounds. This is critical because fires in one room can otherwise go undetected in distant bedrooms.
For hardwired systems, interconnection runs through the third wire (red) in the low-voltage cable. For wireless systems, interconnection uses a proprietary RF protocol. Make sure all your detectors speak the same protocol.
The most common issue I found in testing: mixing brands on the same interconnect chain rarely works. Stick to one brand family for a reliable local alarm system.
UL Certification and Sensor Types
UL 217 is the US safety standard for smoke detectors. The 10th Edition (current as of 2026) added stricter requirements for nuisance alarm resistance. Always look for UL 217 10th Edition certification on the box.
Two sensor types exist: photoelectric (better for smoldering fires) and ionization (better for flaming fires). Dual-sensor units combine both. For most homes, photoelectric is recommended because kitchen fires are typically smoldering.
For CO detection, look for UL 2034 certification. Electrochemical CO sensors are the standard and last about 10 years.
Smart Features and App Controls
Smart features include phone push notifications, remote silence, location announcements, and integration with security systems. Each feature adds complexity and a potential point of failure.
If you want app alerts, you need either a Wi-Fi-connected detector or a base station that bridges RF interconnect to your home network. Wi-Fi units work directly, but they consume more power and can drop offline.
For a true local alarm system, prioritize detectors that sound and interconnect without internet. Add smart features through a base station or hub, not as the primary detector.
Subscription vs No-Subscription Models
Most smart smoke detectors do not require a subscription for phone alerts. The exceptions are SimpliSafe, Ring Protect (for advanced monitoring), and ADT-style services.
No-subscription models from Kidde, X-Sense, eufy, and Heiman send app notifications for free. Subscription models add 24/7 professional monitoring, where a call center contacts you and dispatches fire services if you do not respond.
For most homeowners, free app notifications are sufficient. Professional monitoring is worth the cost only if you travel frequently or care for an elderly relative living alone.
Frequently Asked Questions
Who makes the best smart smoke detector?
Based on my testing, Kidde and X-Sense make the best smart smoke detectors for a local alarm system. Kidde offers hardwired and battery options with Ring integration, while X-Sense delivers excellent 10-year sealed battery units with reliable wireless interconnect. First Alert remains the gold standard for hardwired replacements.
Are smart smoke detectors worth it?
Yes, smart smoke detectors are worth it for most homeowners. They send phone alerts when you are away, which traditional detectors cannot do. According to NFPA data, hardwired interconnected alarms work in 94% of fires versus 85% for battery-only, and smart alerts add an extra layer when nobody is home to hear it.
What smoke detectors do firemen recommend?
Fire departments recommend photoelectric or dual-sensor smoke detectors with UL 217 certification. Most firefighters prefer hardwired interconnected units because they work during power outages and alert every occupant simultaneously. For local alarm systems, photoelectric sensors reduce false alarms from cooking while still detecting smoldering fires quickly.
Can smart smoke detectors work with an existing local alarm system?
Yes, most smart smoke detectors integrate with existing local alarm systems through hardwired interconnect (using the third red wire) or wireless RF interconnect. For hardwired systems, match the brand family (Kidde with Kidde, BRK with First Alert). For wireless systems, ensure all units use the same RF protocol, such as Kidde’s wire-free interconnect or X-Sense’s wireless pairing.
Is the Google Nest Protect discontinued?
Google discontinued the Nest Protect in 2024 and stopped selling new units. Existing Nest Protect detectors continue to function, but Google no longer offers replacements or new generations. For Nest Protect alternatives, the Heiman Smart Wireless 6-Pack + Gateway is the closest match for local control, while the Kidde Smart Smoke Detector with Ring offers app integration for households already in the Ring ecosystem.
Final Verdict
The best smart smoke detector for a local alarm system depends on what you already own. For Ring households, the Kidde Smart Smoke Detector with Ring delivers native integration without forcing you to leave the Ring ecosystem. For eufy households, the E10 is the cleanest addition. For everyone else, the Heiman Smart Wireless 6-Pack + Gateway is the closest replacement for the discontinued Nest Protect.
If budget matters more than smart features, the BRK First Alert 9120B is the workhorse hardwired detector that has earned its 4.7-star rating across 19,296 reviews. For renters and easy installs, the X-Sense SC06-W 3-Pack covers a whole home with reliable wireless interconnect and zero rewiring.
Whatever you choose in 2026, make sure it carries UL 217 certification, matches your existing interconnect protocol, and is UL listed. A smart smoke detector is only as good as its ability to alert you in the first 30 seconds of a fire. Pick one today, test it monthly, and replace the whole network every 10 years.