Winner
Updated November 2026
Data from the official First Alert and Heiman sites.
2026 verdict
Both of these run on batteries, so hazard coverage and app reach make the call: the First Alert SC5 Battery Smart Smoke & CO Alarm wins by combining smoke and carbon monoxide sensing in one unit, sending a fuller set of alerts, and cutting nuisance alarms with steam-check technology, none of which the CO-only Heiman Smart CO Alarm includes. The Heiman Smart CO Alarm trades that for a lower price, a built-in flash light, and Matter-over-Thread integrations that reach Google Home, Alexa, Apple HomeKit, Samsung SmartThings and Home Assistant, well beyond the SC5 Battery, which lists Google Home, no Alexa, Apple HomeKit or SmartThings, and no documented Home Assistant support. Both alarms are rated for roughly a decade on their replaceable batteries, so battery upkeep is a wash between them. Buyers who want a single battery-powered alarm covering both smoke and CO with steam-check tuning should get the First Alert SC5 Battery Smart Smoke & CO Alarm, while anyone who already has smoke detection and wants an affordable CO monitor that plugs into a Matter smart home should choose the Heiman Smart CO Alarm.
Works with
Connectivity
- Wi-Fi 2.4 GHz
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| Feature | First Alert SC5 Battery Smart Smoke & CO Alarm | Heiman Smart CO Alarm | Winner |
|---|---|---|---|
| Integrations | Google Home | Google Home, Alexa, Apple HomeKit, Samsung SmartThings, Home Assistant, Matter | Heiman Smart CO Alarm |
| Sensors | Smoke, CO | CO | First Alert SC5 Battery Smart Smoke & CO Alarm |
| Alerts | Fire Alerts, CO Alerts, Low Battery Alerts | CO Alerts, Low Battery Alerts | First Alert SC5 Battery Smart Smoke & CO Alarm |
| Built-in Light | NO | YES | Heiman Smart CO Alarm |
| Steam Check | YES | NO | First Alert SC5 Battery Smart Smoke & CO Alarm |
| Rating | 3.6 | 3.6 | Tie |
| Battery Life | 10 years | 10 years | Tie |
| Connectivity | 2.4 GHz WiFi | Thread Protocol | Tie |
| Screen | NO | NO | Tie |
| Built-in Siren | YES | YES | Tie |
| Tests Itself | NO | NO | Tie |
| Pathlight | NO | NO | Tie |
Winner
- + Sensors: Smoke, CO
- + Alerts: Fire Alerts, CO Alerts, Low Battery Alerts
- + Steam Check: YES
- - Integrations: Google Home vs Google Home, Alexa, Apple HomeKit, Samsung SmartThings, Home Assistant, Matter
- - Built-in Light: NO vs YES
$59.99
- + Integrations: Google Home, Alexa, Apple HomeKit, Samsung SmartThings, Home Assistant, Matter
- + Built-in Light: YES
- - Sensors: CO vs Smoke, CO
- - Alerts: CO Alerts, Low Battery Alerts vs Fire Alerts, CO Alerts, Low Battery Alerts
Frequently Asked Questions
Which is better overall: the First Alert SC5 Battery Smart Smoke & CO Alarm or the Heiman Smart CO Alarm?
The First Alert SC5 Battery Smart Smoke & CO Alarm wins overall, thanks to combined smoke and CO detection, more alert types, and steam-check tuning. The Heiman Smart CO Alarm still wins on price and integrations breadth.
What is the biggest difference between these two alarms?
Hazard coverage. The First Alert SC5 Battery Smart Smoke & CO Alarm detects both smoke and carbon monoxide, while the Heiman Smart CO Alarm detects carbon monoxide only.
Do both alarms run on batteries?
Yes, both are fully battery-powered with no wiring required, and both are rated for roughly a decade of use on their respective batteries.
Which alarm has broader smart home integrations?
The Heiman Smart CO Alarm, through Matter over Thread, reaches Google Home, Alexa, Apple HomeKit, Samsung SmartThings and Home Assistant. The First Alert SC5 Battery Smart Smoke & CO Alarm works with Google Home, has no Alexa, Apple HomeKit or SmartThings support, and its Home Assistant support is not documented.
Who should buy the First Alert SC5 Battery Smart Smoke & CO Alarm?
Anyone who wants a single battery-only alarm covering both smoke and carbon monoxide, with steam-check tuning to reduce cooking and shower false alarms.
Who should buy the Heiman Smart CO Alarm?
Buyers who already have smoke detection in place and want an affordable carbon monoxide monitor that fits into a Google Home, Alexa, Apple HomeKit or SmartThings setup.
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Compare all 28 Smoke & CO Detectors side by side
You are looking at two of them. The full table lines up all Smoke & CO Detectors in the catalog with the same specs, so you can filter by what you need and sort by price or rating.
- 28 Smoke & CO Detectors
- 45 specs compared
- 42 filters
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HS1SA-E Zigbee Smoke Alarm
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SD19-MN Interconnected Smart Smoke Alarm
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Nest Protect (Battery)
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Smart Smoke Detector
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Smoke Alarm
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XC0M-iR Smart Carbon Monoxide Alarm with Voice Alerts
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Carbon Monoxide Detector C1-S
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Smoke and CO Alarm HM-636THS
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Matter Smoke Detector S1-TM
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Wi-Fi Smoke Alarm
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Smart Smoke & CO Detector with Ring
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Smoke Alarm E10
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Smoke Alarm HM-636PHS
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Interconnected Smoke Alarm S1-R
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Interconnected CO Alarm C1-R
- Door & Window Sensors
Window Door Alarm
- Gas Detectors
HS1CG Series Combustible Gas Sensor
- Gas Detectors
WS2CG Series Combustible Gas Detector
- Motion Sensors
Smart Motion Sensor
- Motion Sensors
WiFi Smart Motion Sensor
- Sirens
Smart Siren HS2WD series
- Smoke & CO Detectors
Carbon Monoxide Detector C1-S
- Smoke & CO Detectors
HS1SA-E Zigbee Smoke Alarm
- Smoke & CO Detectors
Interconnected CO Alarm C1-R
- Smoke & CO Detectors
Interconnected Smoke Alarm S1-R
- Smoke & CO Detectors
Matter Smoke Detector S1-M
- Smoke & CO Detectors
Matter Smoke Detector S1-TM
- Smoke & CO Detectors
Smoke Alarm HM-636PHS
- Smoke & CO Detectors
Smoke and CO Alarm HM-636THS
- Vibration Sensors
Smart Vibration Sensor HS1VS series
- Water Leak Sensors
Smart Water Leakage Sensor