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2nd gen Nest Protect sensors

The 2nd gen Google Nest Protect features an exclusive Split-Spectrum smoke sensor and a microphone that enables complete Self-Monitoring if you forget to manually test it. It also has other sensors that detect temperature, humidity, occupancy, and ambient light.

Nest Protect uses information from its sensors to detect smoke or CO in your home, test itself, light your way in the dark, and more.

Split-Spectrum Sensor

Split-Spectrum Sensor uses two different kinds of light to detect smoke from a wide range of fires, including both fast-flaming and slow smoldering fires, a first for home smoke and CO alarms.

Learn more about the Split-Spectrum Sensor

Carbon monoxide sensor

Carbon monoxide sensor detects carbon monoxide (CO), an odorless, colorless and potentially deadly gas. The CO sensor lasts up to 10 years from the date of manufacture.

Learn more about carbon monoxide

Heat sensor

Heat sensor enables Nest Protect to detect sudden rises in temperature.

Humidity sensor

Humidity sensor enables Steam Check. This Nest Protect exclusive feature uses an advanced software algorithm to reduce nuisance alarms caused by things like steam from your shower.

Learn more about Steam Check

Occupancy sensor

Occupancy sensor detects when you are walking under Nest Protect to turn on Pathlight and light your way in the dark. And if you have a Google Nest Learning Thermostat, the occupancy sensor also helps your system switch to Eco Temperatures, so you can save energy while you’re gone.

Learn more about Pathlight

Learn more about how your thermostat can automatically switch to Eco Temperatures

Ambient light sensor

Ambient light sensor tells Nest Protect when you’ve shut off the lights for the night so it can automatically turn on Nightly Promise and Pathlight.

Learn more about Nightly Promise


Microphone enables 2nd gen Nest Protects to test their speaker and horn each time you run a test. This feature is called Sound Check.

Learn more about Sound Check

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