Winner
Price unavailable right now
Updated November 2026
Data from the official Google and Kidde sites.
2026 verdict
Among battery-powered smart smoke and CO alarms, the Google Nest Protect (Battery) is the more feature-rich of these two, while the Kidde Smart Smoke & CO Detector with Ring is the more affordable.
The Google Nest Protect (Battery) adds occupancy, temperature, humidity, ambient-light and motion sensing plus an automatic pathlight and a monthly self-test, and it works with Google Home and Home Assistant. The Kidde Smart Smoke & CO Detector with Ring counters with free real-time alerts and status in the Ring app, low-level carbon monoxide warnings, wireless interconnect and optional Ring professional monitoring, with no wiring and a lower price. Pick the Google Nest Protect (Battery) for the richer sensing and a Google or Home Assistant home, and the Kidde Smart Smoke & CO Detector with Ring for a Ring household or a cheaper no-wiring install.
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| Feature | Google Nest Protect (Battery) | Kidde Smart Smoke & CO Detector with Ring | Winner |
|---|---|---|---|
| Rating | 4.4 | 4.3 | Google Nest Protect (Battery) |
| Connectivity | 2.4 GHz WiFi, Bluetooth, Other | 2.4 GHz WiFi, Other | Google Nest Protect (Battery) |
| Integrations | Google Home, Home Assistant | Home Assistant | Google Nest Protect (Battery) |
| Sensors | Smoke, CO, Occupancy, Temperature, Humidity, Ambient Light, Motion | Smoke, CO | Google Nest Protect (Battery) |
| Pathlight | YES | NO | Google Nest Protect (Battery) |
| Screen | NO | NO | Tie |
| Alerts | Fire Alerts, CO Alerts, Low Battery Alerts | Fire Alerts, CO Alerts, Low Battery Alerts | Tie |
| Built-in Siren | YES | YES | Tie |
| Steam Check | YES | YES | Tie |
What the differences mean
Sensors
The Google Nest Protect (Battery) adds occupancy, temperature, humidity, ambient-light and motion sensing on top of smoke and CO. The Kidde Smart Smoke & CO Detector with Ring senses smoke and carbon monoxide only.
Pathlight
Only the Google Nest Protect (Battery) has a motion-activated pathlight, which several Kidde owners say they miss coming from a Nest Protect.
Ecosystem
The Kidde Smart Smoke & CO Detector with Ring reports into the Ring app for free and can join optional Ring professional monitoring. The Google Nest Protect (Battery) works with Google Home and Home Assistant, not Ring.
Low-level CO alerts
The Kidde Smart Smoke & CO Detector with Ring lists low-level carbon monoxide mobile alerts that can warn before a conventional alarm would sound. The Google Nest Protect (Battery) does not list that capability.
Battery
The Google Nest Protect (Battery) runs on six Energizer lithium AA cells, said to last years. The Kidde Smart Smoke & CO Detector with Ring runs on two AA batteries, included, and reports its low-battery state in the app.
Self-test
The Google Nest Protect (Battery) checks its sensors over 400 times a day with a monthly report. The Kidde Smart Smoke & CO Detector with Ring has no listed self-test.
Which one to buy if
- you already run a Ring Alarm system
The Kidde Smart Smoke & CO Detector with Ring pairs into the Ring app with free alerts and optional professional monitoring.
- you want an automatic night pathlight
Only the Google Nest Protect (Battery) lights the hallway when you walk under it.
- you want the lowest cost
The Kidde Smart Smoke & CO Detector with Ring is the more affordable of the two.
- you want early spoken warnings and self-testing
The Google Nest Protect (Battery) names the room before the alarm and emails a monthly report.
- you want low-level carbon monoxide warnings
The Kidde Smart Smoke & CO Detector with Ring lists low-level CO mobile alerts.
Winner
Price unavailable right now
- + Rating: 4.4
- + Connectivity: 2.4 GHz WiFi, Bluetooth, Other
- + Integrations: Google Home, Home Assistant
$69.97
- - Rating: 4.3 vs 4.4
- - Connectivity: 2.4 GHz WiFi, Other vs 2.4 GHz WiFi, Bluetooth, Other
What owners say
Google Nest Protect (Battery) owners and Kidde Smart Smoke & CO Detector with Ring owners agree that app alerts and self-monitoring beat a plain beeping detector, and both groups prize the end of midnight low-battery chirps. Kidde Smart Smoke & CO Detector with Ring owners single out how cleanly it slots into a Ring Alarm setup, with free app alerts, wireless interconnect and low-level CO warnings, and several name it the smoothest Nest Protect replacement; a small number report unexplained false alarms and everyone notices the missing night light. Google Nest Protect (Battery) owners love the early spoken warning that names the room, the self-test emails and the pathlight, while warning that stock can be old, the specific lithium batteries are pricey, and there is no Alexa or HomeKit support.
Frequently Asked Questions
Which is better overall: Google Nest Protect (Battery) or Kidde Smart Smoke & CO Detector with Ring?
The Google Nest Protect (Battery) has more sensors, a pathlight and self-testing. The Kidde Smart Smoke & CO Detector with Ring is the better value and the natural pick in a Ring Alarm household, with free app alerts and low-level CO warnings.
What is the biggest difference between the Google Nest Protect (Battery) and the Kidde Smart Smoke & CO Detector with Ring?
Ecosystem and sensors. The Kidde Smart Smoke & CO Detector with Ring lives in the Ring app with optional professional monitoring, while the Google Nest Protect (Battery) is richer in sensing and works with Google Home and Home Assistant.
Does the Kidde Smart Smoke & CO Detector with Ring need a subscription?
No. Smoke, CO and low-battery notifications arrive in the Ring app for free on the Kidde Smart Smoke & CO Detector with Ring. A Ring subscription is optional and adds 24/7 professional monitoring.
Is the Kidde Smart Smoke & CO Detector with Ring a good replacement for a Google Nest Protect?
It is the most common replacement, and owners moving from an end-of-life Google Nest Protect are generally happy. The feature they miss most is the night light, which the Kidde Smart Smoke & CO Detector with Ring does not have.
Do these alarms work with Alexa, Apple HomeKit or Matter?
Neither supports Apple HomeKit or Matter. The Google Nest Protect (Battery) works with Google Home and Home Assistant. The Kidde Smart Smoke & CO Detector with Ring works with the Ring app, with Alexa able to announce alerts through the Ring skill, and Home Assistant can read it through a community integration.
Who should buy the Google Nest Protect (Battery)?
Buyers who want the extra sensors, the pathlight and self-testing, and who are in a Google Home or Home Assistant setup and will accept the higher price and specific lithium batteries.
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Compare all 28 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.
- 28 Smoke & CO Detectors
- 45 specs compared
- 42 filters
- Smoke & CO Detectors
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Smart Smoke Detector
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7% OFF
Smoke Alarm
4.4(558)£64.82£69.74 - Smoke & CO Detectors
Carbon Monoxide Detector C1-S
4.4(151)$29.99 - Smoke & CO Detectors
20% OFFXC0M-iR Smart Carbon Monoxide Alarm with Voice Alerts
4.4(150)£26.32£32.99 - Smoke & CO Detectors
10% OFFSmoke and CO Alarm HM-636THS
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10% OFF
Matter Smoke Detector S1-TM
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15% OFFSD19-MN Interconnected Smart Smoke Alarm
4.4(20)£22.09£25.99 - Smoke & CO Detectors
Wi-Fi Smoke Alarm
4.3(2.4K) - Smoke & CO Detectors
25% OFF
Smoke Alarm E10
4.3(77)£59.99£79.99 - Smoke & CO Detectors
17% OFFSmoke Alarm HM-636PHS
4.2(85)$24.99$29.99 - Smoke & CO Detectors
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4.2(44) - Smoke & CO Detectors
Interconnected CO Alarm C1-R
4.2(27)$31.97 - Smoke & CO Detectors
SC5 Battery Smart Smoke & CO Alarm
3.7(80) - Smoke & CO Detectors
SMCO410 Smoke Detector & CO Alarm
3.6(279)$64.98
- Cameras
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Nest Cam Floodlight
4.4(1.9K)$279.00 - Cameras
Nest Cam Indoor (Wired, 3rd Gen)
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25% OFFNest Cam Outdoor (Wired, 2nd Gen)
4.4(848)$149.99$199.99 - Cameras
Nest Cam (indoor, wired)
4.6(44)$95.99 - Displays
Nest Hub (2nd Gen)
4.2(1.2K)$299.99 - Displays
Nest Hub Max
4.3(215) - Doorbells
22% OFFNest Doorbell (battery)
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11% OFFNest Doorbell (wired, 2nd Gen)
4.3(1K)$160.00$179.99 - Door Locks
7% OFFNest x Yale Lock
4.2(2K)$224.00$239.99 - Routers
Nest WiFi Pro
4.0(2.6K) - Smoke & CO Detectors
Nest Protect (Wired)
4.6(4.6K) - Speakers
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14% OFFNest Mini (2nd gen)
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Nest Learning Thermostat
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