Google Nest Protect

The Google Nest Protect (wired version, model A12) is a hardwired smart smoke and carbon monoxide alarm that connects to Wi-Fi and the Nest app. It suits homes that already have alarm wiring and owners who want phone alerts when they are away. What sets it apart is how it communicates: a spoken voice that names the hazard and the room, a split-spectrum smoke sensor that uses two wavelengths of light, a motion-activated Pathlight, and the ability to hush a nuisance alarm from your phone.

Specifications

Specification	Details
Detects	Smoke (fast and slow burning fires) and carbon monoxide
Smoke sensor	Split-spectrum sensor using two wavelengths of light
CO sensor	Described as a 10-year carbon monoxide sensor; sensor type not stated
Power	Hardwired; listing mentions low-battery alerts, battery type not stated
Connectivity	2.4 GHz Wi-Fi (802.11b/g/n), 802.15.4 wireless interconnect, Bluetooth Low Energy
Alerts	Voice alerts naming hazard and location, early Heads-Up warning, phone notifications, app hush
Extras	Pathlight night light when you walk underneath; 120-degree field of view
Size / model	About 5.3 x 5.3 x 1.5 in; model A12 (S3003LWES); warranty not stated in listing

Google Nest Protect A12 (wired) — split-spectrum smoke + CO, Wi-Fi app alerts, voice location alerts, Pathlight

How It Compares

The Only Listing Here That Lets You Silence an Alarm From Your Phone

We compared this listing with 19 similar ones. Four are smart smoke-and-CO alarms that also send phone alerts: First Alert’s SC5 in battery and hardwired versions, and Kidde’s Ring-connected alarm in battery and hardwired versions. Two of those are hardwired like this Nest. Among all of them, only the Nest listing describes hushing an alarm from the app, a split-spectrum smoke sensor and a built-in night light. The SC5 listings also describe voice alerts that state the type and location of danger, and they say they are compatible with Nest Protect, so the two can work in the same house.

The rest of the shelf is simpler: five X-Sense combination alarms with sealed lithium batteries (two of them wireless-interconnected, none with Wi-Fi), several Kidde and First Alert CO-only alarms, plus three handheld or RV units that are not comparable.

The listing has gaps. Seven similar listings name UL 217, the smoke alarm standard, while the Nest listing names no standard. It also does not state the backup battery type, a warranty term, alarm volume in decibels or whether it interconnects with the existing hardwired alarms in your home. The release date on the listing is 2016, so confirm current app support before buying.

Who It’s For — and Who Should Skip It

Choose the Nest Protect if you are replacing existing hardwired alarms, already use the Google Home or Nest app, and want to know about smoke or CO when traveling or at work. The spoken room location helps in larger or multi-level homes where a horn alone does not tell you where to look.

Skip it if your ceiling box has no alarm wiring (a battery smart alarm is easier), if you do not want a Wi-Fi device on the ceiling, or if you would rather have a listing that names UL certification and a warranty. Kidde’s Ring units and First Alert’s SC5 cover similar ground with those details spelled out more fully.

Using It at Home

Swapping a hardwired alarm involves line-voltage wiring: turn off the breaker, confirm the circuit is dead, then connect the new harness. Many Front Range homes built before the 1990s have older alarm circuits or none at all, so check what the existing box holds before ordering.

• Place units in each bedroom, in hallways outside sleeping areas and on every level, keeping them away from kitchens and bathrooms to cut nuisance alarms.
• Connect to 2.4 GHz Wi-Fi during setup and run the app’s test after installation.
• In homes with gas furnaces, water heaters or attached garages, make sure CO coverage sits within 15 feet of each sleeping room, as Colorado law requires.

Any smoke or CO alarm means leave first and call 911 from outside. If CO warnings repeat without an obvious cause, contact us to have the furnace, water heater and venting evaluated.

Related Guides

• Best smoke and carbon monoxide detectors
• Smoke detector placement
• Carbon monoxide detector installation
• Best CO detector for home

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