In-depth review
First Alert SCO500B Wireless Interconnected Smoke & CO Alarm Review (2027)
In-depth review of the First Alert SCO500B: wireless interconnect for up to 16 units, voice and location alerts, photoelectric smoke and electrochemical CO sensing.
First Alert SCO500B Wireless Interconnected Smoke & CO Alarm
A battery combo alarm that wirelessly interconnects up to 16 units, with voice and location alerts.
Our verdict
The SCO500B is the no-wires answer to whole-home sounding: battery combo alarms that interconnect by RF so one event wakes every floor, with a voice that names the threat and the room. It deliberately skips the cloud, so there are no phone alerts, and its AA batteries and 7-year warranty trail the sealed 10-year class, but for renters and older homes it delivers the multi-story essentials.
What we like
- Wireless interconnect: when one alarm sounds, all sound, across up to 16 compatible units
- Voice alarm announces the threat type and its programmed location
- Photoelectric smoke sensor reduces cooking nuisance alarms, with an electrochemical CO sensor
- Battery powered with a side-load battery drawer, so no electrician and easy swaps
What to watch out for
- No app or phone alerts; the interconnect network is local only
- Runs on replaceable AA batteries rather than a sealed 10-year pack
- 7-year limited warranty is shorter than 10-year class rivals
What owners report: First Alert SCO500B Wireless Interconnected Smoke & CO Alarm
Synthesized from recurring themes in long-term owner feedback.
Most praised
- Voice announcements naming the room and threat end the run-around during a night alarm
- Wireless linking across many units covers a multi-story home with no new wiring
- The side-load battery drawer makes a swap a one-minute job on a step stool
Common complaints
- No phone alerts means an empty house relies on neighbours hearing the alarm
- Replaceable batteries bring back the battery chore sealed models eliminated
- Its warranty cover runs shorter than the longest rivals in the class
Who it is for
Renters and owners of unwired or multi-story homes who want interconnected combo alarms without an electrician.
The wireless network
Up to 16 compatible First Alert wireless alarms form a mesh-style network in which an alarm that detects smoke or CO triggers all of them, and the initiating unit's latch identifies where the event started. For a three-story home with no alarm wiring, that one-sounds-all behavior is the entire safety argument, delivered without opening a wall.
Voice, location, and sensing
The 85 dB horn is paired with a voice alarm that announces the hazard type and the programmed location, which matters at 3 a.m. when a bare siren gives no direction. Sensing is photoelectric for smoke, which resists cooking nuisance alarms, and electrochemical for CO, the standard pairing in this guide.
Battery reality and the missing app
Power is two AA batteries in a side-load drawer, easy to swap but a recurring chore the sealed 10-year designs eliminate, and the warranty runs 7 years. There is no Wi-Fi and no phone alert at any price of accessory; buyers who travel need a connected model from this guide alongside or instead.
Key specifications
- Sensors
- Photoelectric smoke, electrochemical CO
- Power
- Battery, 2 AA (included)
- Interconnect
- Wireless RF, up to 16 compatible units
- Alarm
- 85 dB with voice and location
- Dimensions
- 5.13 x 5.13 x 2.8 in
- Model
- SCO500B
Sources: First Alert product data, CamelCamelCamel, Amazon listing data
Also consider
X-Sense SC07-W Wireless Interconnected
Interconnected combo alarms that all sound together, with a 10-year sealed battery.
Why consider it: Choose the SC07-W for the same wireless interconnect idea on a sealed 10-year battery, with an optional base station path to phone alerts.
- Sensors: Photoelectric smoke, electrochemical CO
- Power: 10-year sealed lithium battery
First Alert Z-Wave Smoke & CO Alarm ZCOMBO
The hub-home combo alarm: Z-Wave alerts through Ring Alarm or SmartThings, no Wi-Fi needed.
Why consider it: Choose the ZCOMBO if you want battery combo sensing that reports into Ring Alarm or SmartThings through a hub.
- Sensors: Photoelectric smoke, electrochemical CO
- Power: 2 AA batteries
Research-based assessment. TrueGear has not hands-on tested this product; this evaluation synthesizes manufacturer specifications, retailer documentation, and published expert reviews.
Questions, answered
How many SCO500B alarms can interconnect?
Up to 16 compatible First Alert wireless-interconnect alarms can join one network, and when one sounds, all sound.
Does it send phone alerts?
No. The SCO500B network is local RF only; there is no Wi-Fi, app, or cloud alerting.