Winner
Updated September 2026
Data from Amazon and official First Alert and Kidde sites.
2026 verdict
Short answer: the First Alert SMCO410 Smoke Detector & CO Alarm is the better smart smoke alarm here, because it also detects carbon monoxide and the Kidde Smart Smoke Alarm (P4010ACS-WF) does not.
It adds a steam check to cut shower and cooking false alarms and reports to a Z-Wave hub such as Ring Alarm, SmartThings or Home Assistant. The Kidde Smart Smoke Alarm (P4010ACS-WF) has its own strengths: it is the cheaper of the two, connects over 2.4 GHz Wi-Fi with no hub, is hardwired for an interconnected house and works with Google Home. Both use a sealed lithium battery rated for 10 years and both come with a 10 year warranty. Pick the First Alert SMCO410 Smoke Detector & CO Alarm for a Z-Wave home that wants CO coverage, and the Kidde Smart Smoke Alarm (P4010ACS-WF) to make wired alarms smart on a budget.
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| Feature | First Alert SMCO410 Smoke Detector & CO Alarm | Kidde Smart Smoke Alarm (P4010ACS-WF) | Winner |
|---|---|---|---|
| Price | $55.99 | $40.79 | Kidde Smart Smoke Alarm (P4010ACS-WF) |
| Rating | 3.5 | 3.2 | First Alert SMCO410 Smoke Detector & CO Alarm |
| Sensors | Smoke, CO | Smoke | First Alert SMCO410 Smoke Detector & CO Alarm |
| Alerts | Fire Alerts, CO Alerts, Low Battery Alerts | Fire Alerts, Low Battery Alerts | First Alert SMCO410 Smoke Detector & CO Alarm |
| Steam Check | YES | NO | First Alert SMCO410 Smoke Detector & CO Alarm |
| Warranty | 10 years | 10 years | Tie |
| Battery Life | 10 years | 10 years | Tie |
| Connectivity | Z-Wave | 2.4 GHz WiFi | Tie |
| Integrations | Samsung SmartThings, Home Assistant | Google Home, Home Assistant | Tie |
| Screen | NO | NO | Tie |
| Built-in Siren | YES | YES | Tie |
| Built-in Light | NO | NO | Tie |
What the differences mean
Carbon monoxide detection
The First Alert SMCO410 Smoke Detector & CO Alarm senses smoke and carbon monoxide and sends CO alerts. The Kidde Smart Smoke Alarm (P4010ACS-WF) is smoke only, so a home needing CO cover would need a separate detector.
How it connects
The First Alert speaks Z-Wave and needs a Z-Wave controller, with no Wi-Fi and no app of its own. The Kidde joins 2.4 GHz Wi-Fi directly and has its own app, so it works without a hub.
Power source
The Kidde is hardwired to household 120 V power with the sealed lithium cell as backup, which suits a house already wired for alarms. The First Alert is battery only, so it can go on any ceiling without an electrician.
Steam check
Only the First Alert lists a steam check, aimed at kitchens and bathrooms where steam sets off ordinary alarms. The Kidde does not list one.
Smart home platforms
The First Alert lists SmartThings and Home Assistant. The Kidde lists Google Home and Home Assistant. Neither supports Alexa, Apple Home or Matter, so Home Assistant is the platform they share.
Which one to buy if
- you need smoke and carbon monoxide protection from one unit
The First Alert SMCO410 Smoke Detector & CO Alarm has both sensors, while the Kidde Smart Smoke Alarm (P4010ACS-WF) has no CO sensor.
- your house is already wired with interconnected alarms
The Kidde Smart Smoke Alarm (P4010ACS-WF) is hardwired and adds Wi-Fi alerts to that setup.
- you run Google Home and have no Z-Wave hub
It joins Wi-Fi directly and lists Google Home, where the First Alert needs a Z-Wave controller to do anything smart.
- your smart home is built on Ring Alarm, SmartThings or Z-Wave in Home Assistant
The First Alert SMCO410 Smoke Detector & CO Alarm reports over Z-Wave, so alarms land in the hub you already use.
Winner
14% OFF
$55.99
$64.98
- + Rating: 3.5
- + Sensors: Smoke, CO
- + Alerts: Fire Alerts, CO Alerts, Low Battery Alerts
- - Price: $55.99 vs $40.79
- + Price: $40.79
- - Rating: 3.2 vs 3.5
- - Sensors: Smoke vs Smoke, CO
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 SMCO410 Smoke Detector & CO Alarm
- Kidde Smart Smoke Alarm (P4010ACS-WF)
Loading price history...
Frequently Asked Questions
Which is better overall: First Alert SMCO410 Smoke Detector & CO Alarm or Kidde Smart Smoke Alarm (P4010ACS-WF)?
The First Alert SMCO410 Smoke Detector & CO Alarm. It detects carbon monoxide as well as smoke, has a steam check and connects over Z-Wave. The Kidde Smart Smoke Alarm (P4010ACS-WF) is the cheaper, Wi-Fi option for a home with wired alarms.
What is the biggest difference between the First Alert SMCO410 Smoke Detector & CO Alarm and the Kidde Smart Smoke Alarm (P4010ACS-WF)?
Sensing and connection. The First Alert SMCO410 Smoke Detector & CO Alarm detects smoke and CO and needs a Z-Wave hub, while the Kidde Smart Smoke Alarm (P4010ACS-WF) detects smoke only but connects straight to Wi-Fi.
Does the Kidde Smart Smoke Alarm (P4010ACS-WF) detect carbon monoxide like the First Alert SMCO410 Smoke Detector & CO Alarm?
No. The Kidde Smart Smoke Alarm (P4010ACS-WF) is smoke only. The First Alert SMCO410 Smoke Detector & CO Alarm has a carbon monoxide sensor and raises CO alerts.
Do the First Alert SMCO410 Smoke Detector & CO Alarm and the Kidde Smart Smoke Alarm (P4010ACS-WF) work with Google Home?
Only the Kidde Smart Smoke Alarm (P4010ACS-WF) lists Google Home. The First Alert SMCO410 Smoke Detector & CO Alarm does not, and it lists SmartThings and Home Assistant instead. Both list Home Assistant.
Who should buy the First Alert SMCO410 Smoke Detector & CO Alarm?
Z-Wave households on Ring Alarm, SmartThings or Home Assistant who want smoke and CO in one alarm, a steam check and a battery-powered unit rated for 10 years.
Who should buy the Kidde Smart Smoke Alarm (P4010ACS-WF)?
Owners of a house wired for interconnected alarms who want phone alerts over Wi-Fi and Google Home support without a hub, and who cover carbon monoxide separately.
Full comparison table
Compare all 24 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.
- 24 Smoke & CO Detectors
- 44 specs compared
- 41 filters
YoLinkPhotoelectric Smoke Alarm
$49.99
HeimanMatter Smoke Detector S1-TM
$49.98
GoogleNest Protect (Wired)
$449.99
X-SenseWi-Fi CO Alarm
X-SenseSC07-MR Smart Smoke & CO Alarm
HeimanHS1SA-E Zigbee Smoke Alarm
€34.99
X-SenseWiFi Smoke & CO Detector
X-SenseWi-Fi Smoke Alarm
GoogleNest Protect (Battery)
$399.99
ShellySmoke Alarm
25% OFF€53.43€39.95
X-SenseXC0M-iR Smart Carbon Monoxide Alarm with Voice Alerts
HeimanInterconnected Smoke Alarm S1-R
$25.99
AqaraSmart Smoke Detector
16% OFF€44.99€37.99
KiddeSmart Smoke & CO Detector with Ring
$69.97
HeimanInterconnected CO Alarm C1-R
10% OFF$29.98$26.99
First AlertSC5 Battery Smart Smoke & CO Alarm
HeimanSmart CO Alarm
17% OFF$59.99$49.99
HeimanMatter Smoke Detector S1-M
$39.99- First Alert
SMCO410 Smoke Detector & CO Alarm
14% OFF$64.98$55.99 
KiddeSmart Smoke + Indoor Air Quality Alarm
$107.47
Smoke & CO DetectorsKiddeSmart Smoke Alarm (P4010ACS-WF)
3.2(316)$40.79- Smoke & CO DetectorsKidde
Smart Smoke & CO Detector with Ring
4.3(454)$69.97 - Smoke & CO DetectorsKidde
Smart Smoke + Indoor Air Quality Alarm
3.3(199)$107.47 
Water Leak SensorsKiddeWiFi Water Leak & Freeze Detector
3.9(737)32% OFF$34.97$23.89