Smoke & CO Detectors · Head to head

First Alert SC5 Battery Smart Smoke & CO Alarm vs X-Sense Wi-Fi Smoke Alarm

Full Smart Smoke & CO Detectors comparison in 2026

Data from Amazon and official First Alert and X-Sense sites.
2026 verdict
Smoke only, or smoke and carbon monoxide?
First Alert SC5 Battery Smart Smoke & CO Alarm
Winner
First Alert SC5 Battery Smart Smoke & CO Alarm

Last recorded price

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The First Alert SC5 Battery Smart Smoke & CO Alarm is the smarter smoke alarm of the two because it watches for both hazards in one unit, where the X-Sense Wi-Fi Smoke Alarm has no CO sensor. It also carries a 10 year warranty against 5, sends CO alerts and has steam check to cut cooking nuisance alarms. The X-Sense Wi-Fi Smoke Alarm is the better reviewed of the two, adds a built-in light, weighs just 92 g and works with Home Assistant, while the SC5 works with Google Home and is aimed at households replacing Nest Protect alarms. Both run on 2.4 GHz Wi-Fi with no hub, neither has a screen or self-test. Choose the First Alert SC5 Battery Smart Smoke & CO Alarm for whole-home protection and the X-Sense Wi-Fi Smoke Alarm as a simple smoke-only add-on.
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FeatureFirst Alert SC5 Battery Smart Smoke & CO AlarmX-Sense Wi-Fi Smoke AlarmWinner
Rating3.84.5X-Sense Wi-Fi Smoke Alarm
Warranty10 years5 yearsFirst Alert SC5 Battery Smart Smoke & CO Alarm
IntegrationsGoogle HomeHome AssistantFirst Alert SC5 Battery Smart Smoke & CO Alarm
SensorsSmoke, COSmokeFirst Alert SC5 Battery Smart Smoke & CO Alarm
AlertsFire Alerts, CO Alerts, Low Battery AlertsFire Alerts, Low Battery AlertsFirst Alert SC5 Battery Smart Smoke & CO Alarm
Built-in LightNOYESX-Sense Wi-Fi Smoke Alarm
Steam CheckYESNOFirst Alert SC5 Battery Smart Smoke & CO Alarm
Battery Life10 years10 yearsTie
Connectivity2.4 GHz WiFi2.4 GHz WiFiTie
ScreenNONOTie
Built-in SirenYESYESTie
Tests ItselfNONOTie

What the differences mean

Carbon monoxide

The First Alert SC5 Battery Smart Smoke & CO Alarm senses smoke and carbon monoxide and sends both kinds of alert. The X-Sense Wi-Fi Smoke Alarm senses smoke only, so a home with gas appliances or a fireplace needs a separate CO detector next to it.

Warranty

10 years for the First Alert SC5 Battery Smart Smoke & CO Alarm against 5 years for the X-Sense Wi-Fi Smoke Alarm. Both run about 10 years on their batteries, so the longer coverage matches the SC5's expected life.

Size and battery

The First Alert SC5 Battery Smart Smoke & CO Alarm is a 146 mm round unit weighing about 16 oz, powered by six CR123A cells. The X-Sense Wi-Fi Smoke Alarm is a 78 mm unit of 92 g on a single CR123A, easier to place on a small ceiling.

Smart home support

The First Alert SC5 Battery Smart Smoke & CO Alarm links into Google Home. The X-Sense Wi-Fi Smoke Alarm has no Google Home or Alexa support and lists only Home Assistant. Neither supports Apple Home or Matter.

Light and nuisance alarms

The X-Sense Wi-Fi Smoke Alarm has a built-in light, which the SC5 lacks. The SC5 has steam check to reduce false alarms from showers and cooking, which the X-Sense does not list.

Which one to buy if

What owners say

Owners of both alarms value phone alerts that reach them when they are away, and a loud built-in siren. First Alert SC5 Battery Smart Smoke & CO Alarm owners single out the easy swap onto an old Nest wall plate, a single Google Home dashboard shared with older alarms and voice alerts that name the hazard and the room, while a recurring share report nuisance false alarms, a clunky extra step in the First Alert app before linking and the loss of the Nest pathlight, and a few saw batteries drain early. X-Sense Wi-Fi Smoke Alarm owners single out pairing that takes minutes with no hub, a solid build and real-time notifications, and they mention that it has no CO sensor, no automatic self-test and an app some found only in English.

Price history compared

Every price change of both, in the same store, so the gap between the two lines is what one costs more than the other.

  • First Alert SC5 Battery Smart Smoke & CO Alarm
  • X-Sense Wi-Fi Smoke Alarm

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Frequently Asked Questions

Which is better overall: First Alert SC5 Battery Smart Smoke & CO Alarm or X-Sense Wi-Fi Smoke Alarm?

The First Alert SC5 Battery Smart Smoke & CO Alarm, because it detects both smoke and carbon monoxide and has a 10 year warranty. The X-Sense Wi-Fi Smoke Alarm is the better reviewed and works as a simple smoke-only alarm.

What is the biggest difference between the First Alert SC5 Battery Smart Smoke & CO Alarm and the X-Sense Wi-Fi Smoke Alarm?

Carbon monoxide detection. The First Alert SC5 Battery Smart Smoke & CO Alarm has it and the X-Sense Wi-Fi Smoke Alarm does not.

Does the X-Sense Wi-Fi Smoke Alarm detect carbon monoxide?

No. The X-Sense Wi-Fi Smoke Alarm is a smoke-only alarm with no CO alerts. The First Alert SC5 Battery Smart Smoke & CO Alarm detects both.

Do the First Alert SC5 Battery Smart Smoke & CO Alarm and the X-Sense Wi-Fi Smoke Alarm work with Alexa?

Neither does. The First Alert SC5 Battery Smart Smoke & CO Alarm works with Google Home and the X-Sense Wi-Fi Smoke Alarm with Home Assistant, and both connect over 2.4 GHz Wi-Fi without a hub.

Who should buy the First Alert SC5 Battery Smart Smoke & CO Alarm?

Google Home households, especially those replacing Nest Protect, who want smoke and CO protection in one battery alarm and a long warranty.

Who should buy the X-Sense Wi-Fi Smoke Alarm?

Buyers who want a simple, compact smoke alarm with phone alerts and a built-in light, in a home where CO is covered by another detector.

Full comparison table

Compare all 25 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.

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