Google Nest Protect (Wired) vs Heiman Smart CO Alarm (2026)

Updated September 2026

Data from Amazon and official Google and Heiman sites.

2026 verdict

Winner

$400.00

For an all-in-one hardwired alarm versus a compact CO specialist, the Google Nest Protect (Wired) takes this comparison with a richer sensor suite, smoke, CO, occupancy, temperature, humidity, ambient light and motion, versus the Heiman Smart CO Alarm's CO-only sensor, a higher owner rating, self-testing, an automatic pathlight, and steam-check false-alarm filtering. The Heiman Smart CO Alarm isn't without an edge of its own: a lower price and a wider integrations list through Matter over Thread, covering Google Home, Alexa, Apple HomeKit, Samsung SmartThings and Home Assistant, one more platform than the wired Nest Protect's Google Home and Home Assistant support. Installation differs too: the Nest Protect (Wired) runs on household power with an AA battery backup, so it needs existing alarm wiring, while the Heiman runs entirely on a replaceable battery and can go almost anywhere. Homes with hardwired alarm circuits that want deep sensing and a full smoke-and-CO alarm should choose the Google Nest Protect (Wired), while anyone needing an affordable, wire-free CO monitor with wide platform reach should pick the Heiman Smart CO Alarm.

Winner

Google

Google Nest Protect (Wired)

$400.00

Buy on Amazon USA

Heiman

Heiman Smart CO Alarm

17% OFF

$49.99

$59.99

Buy on Amazon USA

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Feature	Google Nest Protect (Wired)	Heiman Smart CO Alarm	Winner
Price	$400.00	$49.99	Heiman Smart CO Alarm
Rating	4.6	3.6	Google Nest Protect (Wired)
Connectivity	2.4 GHz WiFi, Bluetooth, Other	Thread Protocol	Google Nest Protect (Wired)
Integrations	Google Home, Home Assistant	Google Home, Alexa, Apple HomeKit, Samsung SmartThings, Home Assistant, Matter	Heiman Smart CO Alarm
Sensors	Smoke, CO, Occupancy, Temperature, Humidity, Ambient Light, Motion	CO	Google Nest Protect (Wired)
Alerts	Fire Alerts, CO Alerts, Low Battery Alerts	CO Alerts, Low Battery Alerts	Google Nest Protect (Wired)
Tests Itself	YES	NO	Google Nest Protect (Wired)
Pathlight	YES	NO	Google Nest Protect (Wired)
Steam Check	YES	NO	Google Nest Protect (Wired)
Screen	NO	NO	Tie
Built-in Siren	YES	YES	Tie
Built-in Light	YES	YES	Tie

Winner

Google

Google Nest Protect (Wired)

$400.00

Buy on Amazon USA

+ Rating: 4.6
+ Connectivity: 2.4 GHz WiFi, Bluetooth, Other
+ Sensors: Smoke, CO, Occupancy, Temperature, Humidity, Ambient Light, Motion
- Price: $400.00 vs $49.99
- Integrations: Google Home, Home Assistant vs Google Home, Alexa, Apple HomeKit, Samsung SmartThings, Home Assistant, Matter

Heiman

Heiman Smart CO Alarm

17% OFF

$49.99

$59.99

Buy on Amazon USA

+ Price: $49.99
+ Integrations: Google Home, Alexa, Apple HomeKit, Samsung SmartThings, Home Assistant, Matter
- Rating: 3.6 vs 4.6
- Connectivity: Thread Protocol vs 2.4 GHz WiFi, Bluetooth, Other

Frequently Asked Questions

Which is better overall: the Google Nest Protect (Wired) or the Heiman Smart CO Alarm?

The Google Nest Protect (Wired) wins overall on sensor breadth, owner rating, self-testing and pathlight. The Heiman Smart CO Alarm still wins on price and integrations reach.

What is the biggest difference between these two alarms?

Sensor scope and installation type. The Google Nest Protect (Wired) covers smoke, CO, occupancy, temperature, humidity, ambient light and motion, and runs on household power with a battery backup, while the Heiman Smart CO Alarm only detects carbon monoxide and runs entirely on a replaceable battery.

Does the Heiman Smart CO Alarm need wiring like the Nest Protect (Wired)?

No. The Heiman Smart CO Alarm is fully battery-powered and needs no electrical wiring, only a Thread Border Router to enable its smart home integrations. The Google Nest Protect (Wired) requires existing alarm wiring.

Which alarm supports more smart home platforms?

The Heiman Smart CO Alarm, via Matter over Thread, reaches Google Home, Alexa, Apple HomeKit, Samsung SmartThings and Home Assistant, one more platform than the Google Nest Protect (Wired), which works with Google Home and Home Assistant.

Who should buy the Google Nest Protect (Wired)?

Homes with existing hardwired alarm circuits that want one alarm covering smoke, carbon monoxide, and a full extra sensor suite, along with self-testing and an automatic pathlight.

Who should buy the Heiman Smart CO Alarm?

Buyers without alarm wiring who just need an affordable, battery-powered carbon monoxide monitor that reaches Google Home, Alexa, Apple HomeKit or SmartThings.

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