Winner
Updated October 2026
Data from the official First Alert and X-Sense sites.
2026 verdict
Choosing between whole-house hazard coverage and a dedicated CO gadget, the First Alert SC5 Hardwire Smart Smoke & CO Alarm takes this smoke and CO alarm matchup by combining smoke and carbon monoxide sensing in one hardwired unit, backed by Google Home integration, steam-check tuning, and a 10-year warranty. The X-Sense Wi-Fi Carbon Monoxide Alarm brings a friendlier price, higher owner rating, and a large LCD screen showing live CO readings plus a built-in light, but it detects carbon monoxide only and has no smart home integrations at all. The two also differ in setup: the SC5 Hardwire runs on mains power with a battery backup, while the freestanding X-Sense unit runs entirely on a replaceable battery and needs no wiring or wall mount. Households wanting one hardwired alarm that covers both smoke and CO with app alerts should choose the First Alert SC5 Hardwire Smart Smoke & CO Alarm, while anyone who already has smoke coverage and just needs an affordable standalone CO monitor for a boiler room or garage should get the X-Sense Wi-Fi Carbon Monoxide Alarm.
Works with
Connectivity
- Wi-Fi 2.4 GHz
vs
Works with
Connectivity
- Wi-Fi 2.4 GHz
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| Feature | First Alert SC5 Hardwire Smart Smoke & CO Alarm | X-Sense Wi-Fi Carbon Monoxide Alarm | Winner |
|---|---|---|---|
| Rating | 3.5 | 4.6 | X-Sense Wi-Fi Carbon Monoxide Alarm |
| Warranty | 10 years | 5 years | First Alert SC5 Hardwire Smart Smoke & CO Alarm |
| Integrations | Google Home | Home Assistant | First Alert SC5 Hardwire Smart Smoke & CO Alarm |
| Screen | NO | YES | X-Sense Wi-Fi Carbon Monoxide Alarm |
| Sensors | Smoke, CO | CO | First Alert SC5 Hardwire Smart Smoke & CO Alarm |
| Alerts | Fire Alerts, CO Alerts, Low Battery Alerts | CO Alerts, Low Battery Alerts | First Alert SC5 Hardwire Smart Smoke & CO Alarm |
| Built-in Light | NO | YES | X-Sense Wi-Fi Carbon Monoxide Alarm |
| Steam Check | YES | NO | First Alert SC5 Hardwire Smart Smoke & CO Alarm |
| Connectivity | 2.4 GHz WiFi | 2.4 GHz WiFi | Tie |
| Built-in Siren | YES | YES | Tie |
| Tests Itself | NO | NO | Tie |
| Pathlight | NO | NO | Tie |
Winner
- + Warranty: 10 years
- + Integrations: Google Home
- + Sensors: Smoke, CO
- - Rating: 3.5 vs 4.6
- - Screen: NO vs YES
15% OFF
£30.59
£35.99
- + Rating: 4.6
- + Screen: YES
- + Built-in Light: YES
- - Warranty: 5 years vs 10 years
- - Integrations: Home Assistant vs Google Home
Frequently Asked Questions
Which is better overall: the First Alert SC5 Hardwire Smart Smoke & CO Alarm or the X-Sense Wi-Fi Carbon Monoxide Alarm?
The First Alert SC5 Hardwire Smart Smoke & CO Alarm wins overall, since it detects both smoke and carbon monoxide, integrates with Google Home, and carries a longer warranty. The X-Sense Wi-Fi Carbon Monoxide Alarm's strengths are its price, rating, and LCD screen.
What is the biggest difference between these two alarms?
Hazard coverage. The First Alert SC5 Hardwire Smart Smoke & CO Alarm detects smoke and carbon monoxide together and is hardwired with a battery backup, while the X-Sense Wi-Fi Carbon Monoxide Alarm is a battery-only, carbon-monoxide-only device with no smoke sensor.
Does the X-Sense Wi-Fi Carbon Monoxide Alarm work with Google Home or Alexa?
No. It has no smart home platform integrations at all and connects only to its own app over WiFi. The First Alert SC5 Hardwire Smart Smoke & CO Alarm integrates with Google Home.
Which alarm shows a live CO reading on a screen?
The X-Sense Wi-Fi Carbon Monoxide Alarm has a large LCD screen displaying the live carbon monoxide level. The First Alert SC5 Hardwire Smart Smoke & CO Alarm has no display.
Who should buy the First Alert SC5 Hardwire Smart Smoke & CO Alarm?
Homeowners with existing alarm wiring who want a single hardwired device covering both smoke and carbon monoxide, with Google Home alerts and steam-check false-alarm filtering.
Who should buy the X-Sense Wi-Fi Carbon Monoxide Alarm?
Anyone who already has smoke detection covered and just needs an affordable, freestanding carbon monoxide monitor, for example near a gas boiler or wood stove, without any smart home integration requirement.
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Compare all 27 Smoke & CO Detectors side by side
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- 27 Smoke & CO Detectors
- 44 specs compared
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