First Alert Combination Smoke & Carbon Monoxide Alarm, Interconnect Hardwire Detector with Battery Backup, SMICO100-AC, 1-Pack
First Alert · 3 more picks →
Best for
Best hardwired with backup
Amazon rating
Amazon aggregate, one input among many in the Verdict Score
Current price
$49.51
Updated Jun 27, 2026 · 1 min read
The consensus
What reviewers found
Synthesized across the trust-weighted source mix below.
Among the reviewers we read, the First Alert SMICO100-AC earns solid marks as a hardwired combination smoke and carbon monoxide alarm with battery backup, sitting at a 4.4-star average across roughly 1,477 ratings. Verified-purchase buyers favor it as a direct replacement for aging hardwired alarms, citing the interconnect capability that ties it into an existing wired chain so all units sound together. The battery backup is repeatedly mentioned as reassurance during power outages.
What reviewers liked
- Large verified-purchase base (1,477 ratings) at 4.4 stars
- Hardwired with battery backup for outage protection
- Interconnects with existing wired alarm chains
Where it falls short
- Requires hardwired installation, not a plug-and-play retrofit
- No expert or lab testing present in the supplied signals
- Smart/app functionality is limited compared to Wi-Fi-connected models in the category
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Among the reviewers we read, the First Alert SMICO100-AC earns solid marks as a hardwired combination smoke and carbon monoxide alarm with battery backup, sitting at a 4.4-star average across roughly 1,477 ratings. Verified-purchase buyers favor it as a direct replacement for aging hardwired alarms, citing the interconnect capability that ties it into an existing wired chain so all units sound together. The battery backup is repeatedly mentioned as reassurance during power outages.
As with everything in this pool, the available evidence is limited to customer ratings, no independent testing lab, expert publication, or specialist forum thread was supplied for this unit. The healthy review count and consistent average suggest dependable real-world performance for retrofit installs, but claims about detection speed or nuisance-alarm behavior can't be verified from the data.
It's the natural choice for homes with existing interconnected wiring that want combined smoke and CO protection with outage backup, provided buyers are comfortable with basic hardwired installation.
- First Alerts Precision Detection advanced sensing technology complies with new industry standards to reduce cooking nuisance alarms and provides early warning in the event of a home fire emergency
- Through early warning interconnect, when one alarm sounds, all compatible
- Quick Connect Plug allows for easy installation with no need to rewire
- Battery backup provides continuous protection during power outages
- Test/silence button for efficient testing to ensure alarm is working properly
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