First Alert Battery Smoke Alarm
- Smoke Detectors & Fire Alarm
- Battery
- Ionization
- 2
- Better rated than 80%
- More reviewed than 90%
A straightforward battery smoke alarm for anyone who wants easy installation and simple upkeep without electrical work.
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How it ranks among the 10 smoke detectors & fire alarms we track
4.6★ across 5,600 Amazon ratings, Bayesian-smoothed toward the category average.
5,600 Amazon ratings, weighted on a log scale so huge counts don't drown everything.
10,000+ bought on Amazon last month.
Brand identity, imagery, description and spec coverage.
The ProductDome score is separate from the Amazon rating shown above: it combines the Bayesian-smoothed Amazon rating with evidence volume, tracked demand, and data quality across the 10 smoke detectors & fire alarms we track - how the scorecard works · full smoke detectors & fire alarms data report. Confidence: high - strong rating volume and complete data.Updated 7 days ago. Data-computed, not a hands-on test. Compiled by the ProductDome Research Team.
Overview
The First Alert SMI100 is a battery-operated smoke alarm using First Alert's Precision Detection sensing, built to meet current industry standards for reducing cooking-related false alarms while still catching real fires early.
This is a battery unit rather than a hardwired one, so installation is just mounting and inserting a battery, no electrician or wiring needed. A front-access battery compartment and an end-of-life warning are the two features aimed squarely at keeping upkeep simple over the years.
- Battery operated smoke alarm
- Precision Detection sensing
- Front access battery compartment
- End-of-life warning
Who it's for
Good for a homeowner or renter replacing an aging smoke alarm or adding coverage to a room where running new wiring is not practical. Anyone wanting whole-home interconnected hardwired alarms should look at a hardwired First Alert model instead.
Strengths and trade-offs
Drawn from this product's published specifications.
- Battery operated, no wiring required
- Front access battery compartment for easy swaps
- End-of-life warning built in
- Precision Detection sensing reduces cooking nuisance alarms
- Smoke detection only, no carbon monoxide sensing
- Runs on a replaceable battery rather than a sealed 10 year cell
Performance notes
Precision Detection sensing is tuned to meet newer industry standards aimed at cutting down nuisance alarms from cooking smoke while still responding to genuine fire conditions. The front-access battery compartment means swapping the battery does not require removing the whole unit from its mount, and an end-of-life warning signals when the alarm itself needs replacing rather than just the battery.
Specifications
| Brand | First Alert |
|---|---|
| Model | SMI100 |
| Dimensions & fit | |
| Item Weight | 9.6 ounces |
| Item Dimensions D x W x H | 5.6 × 5.6 × 1.9 inches |
| Power & efficiency | |
| Power Source | Battery |
| Construction & materials | |
| Color | White |
| Included components | |
| Unit Count | 2 |
| Other details | |
| Sensor Type | Ionization |
| Number of Items | 2 |
| BuiltIn Media | 9V Alkaline Battery |
| Mfr Part Number | SMI100 |
| Product Style | Precision Detection |
| Alarm | Smoke |
| Item Highlight | SMI100 |
| Item Type Name | Smoke Alarm |
Other First Alert smoke detectors & fire alarms
How it compares
This product against the closest alternatives we track in smoke detectors & fire alarms.
| Product | Amazon rating | Ratings | ProductDome score |
|---|---|---|---|
| First Alert Battery Smoke AlarmThis product | 4.6 / 5 | 5,600 | 4.7 / 5 |
| X-Sense Smoke Detector Carbon Monoxide Detector ComboX-Sense | 4.5 / 5 | 4,200 | 4.5 / 5 |
| Kidde Compact Smoke DetectorKidde | 4.5 / 5 | 940 | 4.3 / 5 |
| Kidde 21007584 I4618 Firex Hardwire Ionization Smoke Detector with Battery BackupwhiteKidde | 4.3 / 5 | 398 | 4.2 / 5 |
| Kidde Smoke DetectorKidde | 4.0 / 5 | 1,400 | 4.2 / 5 |
Similar smoke detectors & fire alarms from other brands
Questions about the First Alert SMI100
Common buyer questions answered straight from the product spec data - no fluff, no "it depends".
Does the First Alert SMI100 detect carbon monoxide?
No, it is a smoke-only alarm and does not include CO sensing.
How do you replace the battery in the SMI100?
The battery compartment is front-access, so it opens without needing to remove the alarm from its mounting bracket.
Does the SMI100 warn you when it needs to be replaced?
Yes, it has an end-of-life warning that signals when the alarm itself, not just the battery, is due for replacement.