BRK First Alert 9120BFF/ SMI100-AC Smoke Detector
Hardwired Alarm with Battery Backup, White, 1-Pack
Price as of 2026-06-05. Check Amazon for the current price.
Quick Decision
Price Intelligence
Currently $18.99 — the 90-day average is $16.50.
All-time low: $7.60 on Sun Nov 30 (from 182 price checks).
Is This Right For You?
- •Budget-conscious shoppers — priced below 95% of Smoke Detectors
- •Those who want a top-rated option — in the top 5% of Smoke Detectors by rating
- •Risk-averse buyers — 19,205+ reviews give a highly reliable picture
📊 Based on data analysis of 37 products in this category.
Mubboo Score: A+
How It Compares
This Product BRK First Alert 9120BFF/ SMI100-AC Smoke Detector | Most Popular First Alert Smoke Alarm | Best Rated Kidde Smoke Detector | Best Value First Alert Smoke Alarm | |
|---|---|---|---|---|
| Price | $18.99 | $24.47 | $19.88 | $16.99 |
| Rating | 4.7/5 | 4.4/5 | 4.6/5 | 4.6/5 |
| Reviews | 19,205 | 8,237 | 7,603 | 4,421 |
| Mubboo Score | A+ | A | A+ | A+ |
Quick Specs
- Alarm
- Audible
- Color
- White
- Style
- 9120BFF
- Unit Count
- 1.0 Count
- Item Weight
- 12.8 ounces
- Sensor Type
- Ionization
- Manufacturer
- First Alert
- Model Number
- 9120B
What People Say
Synthesized from 40 reviews · 100% verified purchases.
Test units upon arrival, as included batteries may be dead or drain quickly. Verify activation tab functions and note that sealed-battery models may not interconnect with other alarms.
- Ease of Installation
- Good Value
- Reliable Performance / No False Alarms
- Compatibility with Existing Mounts
- Long Battery Life / No Battery Changes
- Pre-installed Battery Drains Quickly
- Dead on Arrival / Activation Issues
- Flimsy Build Quality
- Confusing Instructions
Expert Picks in Smoke Detectors
- Kidde Smart Smoke Detector — Best smoke detector overall
- First Alert Battery Smart Smoke & Carbon Monoxide Alarm with Nest Protect — Best for Google Nest users
- Kidde Ring-Enabled Smart Smoke and Carbon Monoxide Detector — Best smoke detector for Alexa and Ring users
- First Alert SMI100 Dual Sensor Smoke Detector — Best budget smoke detector
Category recommendations from independent expert publications. Source links in References.
Related Video Reviews
Key Features
- ✦Keep your family safe with this hardwired smoke alarm the battery backup means constant monitoring, even if there's a power failure
- ✦Equipped with an ionization sensor, this smoke alarm reliably detects smoke from fast flaming fires and alerts you with an 85 decibel alarm
- ✦To ensure complete protection make sure to place one on each level of your home and in each bedroom
- ✦Can connect to other compatible BRK or first alert smoke detectors, to ensure all alarms will sound when smoke is detected
- ✦Simple to use, with a single test/silence button, and side load battery compartment tamper resistant locking brackets and universal mounting brackets make installation easy
Source: product listing on Amazon.
About BRK
- 13 products in our database
- Average rating: 4.8/5 across all products
- Price range: $18.99 – $233.98
- Categories: Carbon Monoxide Detectors, Smoke Detectors
Other Smoke Detectors
Featured in Our Reviews
Bottom Line
BRK First Alert 9120BFF/ SMI100-AC Smoke Detector earns Mubboo Score A+. At $19 it's above the 90-day average of $17 — waiting for a dip may pay off. Rated 4.7/5 from 19,205+ reviews. Strong buy if: budget-conscious shoppers, those who want a top-rated option.
Frequently Asked Questions
Is the BRK First Alert 9120BFF/ SMI100-AC Smoke Detector worth buying in 2026?
It earns a Mubboo Score of A+, with a 4.7/5 rating from 19,205 reviews — better than 95% of Smoke Detectors we track.
How much does the BRK First Alert 9120BFF/ SMI100-AC Smoke Detector cost?
It is currently $18.99. The 90-day average is $16.50 and the all-time low we recorded is $7.60.
How does the First Alert 9120BFF/ SMI100-AC Smoke Detector compare to other Smoke Detectors?
The category's most-reviewed alternative is the First Alert Smoke Alarm (4.4/5, 8,237 reviews, $24.47). The First Alert 9120BFF/ SMI100-AC Smoke Detector carries a Mubboo Score of A+ vs A.
Sources & References
Mubboo may earn a commission from purchases made through links on this page. Prices and availability are accurate as of the last sync (2026-06-05) and may change.