Updated September 2026
Data from Amazon and official Kidde and Shelly sites.
2026 verdict
Shelly Plus Smoke Alarm edges out Kidde Smart Smoke + Indoor Air Quality Alarm in 2026, led by price, rating, and connectivity.
What pushes it ahead is price, rating, and connectivity, and integrations keep the advantage from looking narrow. The only strong reason to choose Kidde Smart Smoke + Indoor Air Quality Alarm is if warranty, sensors, and alerts are more important to you than the overall verdict. For most setups, Shelly Plus Smoke Alarm is the smarter buy.
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| Feature | Kidde Smart Smoke + Indoor Air Quality Alarm | Shelly Plus Smoke Alarm | Winner |
|---|---|---|---|
| Price | $104.86 | €39.95 | Shelly Plus Smoke Alarm |
| Rating | 3.3 | 4.4 | Shelly Plus Smoke Alarm |
| Warranty | 10 years | 3 years | Kidde Smart Smoke + Indoor Air Quality Alarm |
| Connectivity | 2.4 GHz WiFi | 2.4 GHz WiFi, Bluetooth | Shelly Plus Smoke Alarm |
| Integrations | Google Home, Alexa, Home Assistant | Google Home, Alexa, Samsung SmartThings, Home Assistant | Shelly Plus Smoke Alarm |
| Sensors | Smoke, Humidity, Air Quality | Smoke | Kidde Smart Smoke + Indoor Air Quality Alarm |
| Alerts | Fire Alerts, Low Battery Alerts, Air Quality Alerts | Fire Alerts, Low Battery Alerts | Kidde Smart Smoke + Indoor Air Quality Alarm |
| Screen | NO | NO | Tie |
| Built-in Siren | YES | YES | Tie |
| Built-in Light | YES | YES | Tie |
| Tests Itself | NO | NO | Tie |
| Pathlight | NO | NO | Tie |
$104.86
- + Warranty: 10 years
- + Sensors: Smoke, Humidity, Air Quality
- + Alerts: Fire Alerts, Low Battery Alerts, Air Quality Alerts
- - Price: $104.86 vs €39.95
- - Rating: 3.3 vs 4.4
Winner
25% OFF
€39.95
€53.43
- + Price: €39.95
- + Rating: 4.4
- + Connectivity: 2.4 GHz WiFi, Bluetooth
- - Warranty: 3 years vs 10 years
- - Sensors: Smoke vs Smoke, Humidity, Air Quality
Frequently Asked Questions
Which is better overall: Kidde Smart Smoke + Indoor Air Quality Alarm or Shelly Plus Smoke Alarm?
Shelly Plus Smoke Alarm has the stronger overall profile in this comparison, especially for price, rating, and connectivity.
What is the biggest difference between Kidde Smart Smoke + Indoor Air Quality Alarm and Shelly Plus Smoke Alarm?
Price is one of the clearest differences: Kidde Smart Smoke + Indoor Air Quality Alarm lists $104.86, while Shelly Plus Smoke Alarm lists €39.95.
Which one looks better on price?
Kidde Smart Smoke + Indoor Air Quality Alarm is listed at $104.86, while Shelly Plus Smoke Alarm is listed at €39.95. Shelly Plus Smoke Alarm (better spec).
Who should buy Kidde Smart Smoke + Indoor Air Quality Alarm?
Choose Kidde Smart Smoke + Indoor Air Quality Alarm if your priority is warranty and sensors and that matters more than price.
Who should buy Shelly Plus Smoke Alarm?
Choose Shelly Plus Smoke Alarm if your priority is price and rating and that matters more than warranty.
Full comparison table
Compare all 21 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.
- 21 Smoke & CO Detectors
- 44 specs compared
- 41 filters
YoLinkPhotoelectric Smoke Alarm
$49.99
X-SenseWi-Fi CO Alarm
X-SenseSC07-MR Smart Smoke & CO Alarm
HeimanHS1SA Series Smoke Alarm
5% OFF£16.99£16.14
X-SenseWiFi Smoke & CO Detector
X-SenseWi-Fi Smoke Alarm
GoogleNest Protect (Battery)
$400.00
GoogleNest Protect (Wired)
$449.99
ShellySmoke Alarm
25% OFF€53.43€39.95
X-SenseXC0M-iR Smart Carbon Monoxide Alarm with Voice Alerts
AqaraSmart Smoke Detector
16% OFF€44.99€37.99
KiddeSmart Smoke & CO Detector with Ring
$69.97
First AlertSC5 Battery Smart Smoke & CO Alarm
C$169.99
HeimanSmart CO Alarm
20% OFF$59.99$47.99
HeimanMatter Smoke Detector S1-M
$39.99
First AlertSMCO410 Smoke Detector & CO Alarm
$64.98- Kidde
Smart Smoke + Indoor Air Quality Alarm
$104.86 
First AlertSC5 Hardwire Smart Smoke & CO Alarm
C$169.99
KiddeSmart Smoke Alarm (P4010ACS-WF)
$40.79
X-SenseSD19-MN Interconnected Smart Smoke Alarm
33% OFF$32.99$21.99
- Smoke & CO DetectorsKidde
Smart Smoke Alarm (P4010ACS-WF)
3.2(317)$40.79 - Smoke & CO DetectorsKidde
Smart Smoke & CO Detector with Ring
4.3(434)$69.97 - Smoke & CO DetectorsKidde
Smart Smoke + Indoor Air Quality Alarm
3.3(198)$104.86 
Water Leak SensorsKiddeWiFi Water Leak & Freeze Detector
3.9(738)51% OFF$34.97$17.14
CamerasShellyCamera
DisplaysShellyWall Display X1i
DisplaysShellyWall Display XL
4.2(62)$349.99
DisplaysShellyWall Display
4.4(434)18% OFF€147.56€121.33
Door & Window SensorsShellyBLU Door/Window ZB
4.7(25)$22.99
Energy MonitorsShelly3EM-63W Gen3
4.6(137)
Energy MonitorsShellyEM Gen3
4.6(262)$69.99
Energy MonitorsShellyEM Gen4
Energy MonitorsShellyEM Mini Gen4
4.5(120)$24.99
Energy MonitorsShellyPro 3EM 3CT63
4.4(330)$150.99
Energy MonitorsShellyPro 3EM-400
4.3(21)$329.99
Energy MonitorsShellyPro 3EM v2
4.5(69)$154.99
Energy MonitorsShellyPro EM-50
4.6(957)$119.99
Gas DetectorsShellyGAS (CNG)
4.2(45)
Gas DetectorsShellyGAS (LPG)
LED BulbsShellyMulticolor Bulb E27 Gen3
4.3(28)
Motion SensorsShellyBLU Motion ZB
4.6(36)$26.99
Motion SensorsShellyBlu Motion
4.0(1,032)$25.99
PlugsShellyPlug M Gen3
4.5(757)$14.99
PlugsShellyPlug PM Gen3