Critical July 2026 update: Google’s current support pages say Nest Protect is no longer available for sale, but remains supported. Existing second-generation units can still be managed through supported Nest or Google Home app routes. US owners who need a compatible replacement are directed to the First Alert SC5 Smart Smoke & Carbon Monoxide Alarm. This review is therefore for existing-owner support, expiry planning, and safe replacement—not for recommending a new Nest Protect purchase.
Quick verdict for existing owners
Keep an installed Nest Protect only while the exact unit remains within its certified life, passes the manufacturer’s tests, has no fault or end-of-life warning, meets current local placement and interconnection requirements, and has an approved replacement plan. Do not buy old stock without checking the manufacture date: Google’s replacement guidance says a second-generation Nest Protect must be replaced 10 years after manufacture.
App notifications, Pathlight, voice messages, remote status, and smart-home visibility are secondary. The life-safety job is direct local smoke and carbon-monoxide detection and warning. Never delay evacuation, emergency calling, or a required replacement because an app looks normal.
Current official status
| Question | Current record | Owner action |
|---|---|---|
| Can I buy a new Nest Protect? | Google’s current app-control support page says Nest Protect is no longer available for sale but remains supported | Do not treat marketplace or old-stock availability as a current Google sale; verify manufacture date, region, certification, condition, warranty, and seller |
| How long does it last? | Google says second-generation units require replacement 10 years after manufacture | Read the printed date, app status, and replacement date for every unit; do not calculate from the installation date alone |
| What is the US replacement route? | Google points US customers to the First Alert SC5; First Alert’s SC5 page describes Google Home and Nest Protect compatibility | Check the exact battery or hardwired model, local code, mounting, interconnect, app, household, and acceptance requirements before purchase |
| Is support frozen? | Google still publishes setup, app, sensor, interconnect, expiry, and software records; its software history lists second-generation update 3.6 released in March 2025 | Record current software, device status, account access, tests, faults, and support path; do not assume support has a guaranteed end date |
What Nest Protect still does
Google’s second-generation sensor record describes the split-spectrum smoke sensor, carbon-monoxide sensor, heat sensor, humidity sensor, occupancy sensor, ambient-light sensor, and microphone used for sound checks. These parts support different product functions. An occupancy or light sensor does not detect smoke or CO, and an app connection does not replace the local alarm.
- Direct local warning: the unit must detect and sound locally even if a phone, account, router, or internet connection is unavailable.
- Voice and location context: approved naming can help occupants understand the type and location of a warning.
- Wireless interconnect: Google’s interconnect guidance explains that compatible Protect units communicate with each other and can continue doing so when Wi-Fi is down.
- App routes: supported app setup can add notifications, status, and approved controls, but app delivery is not the primary life-safety warning.
- Expiry and fault behavior: the owner must act on chirps, faults, sensor failure, power trouble, app warnings, and end-of-life notices.
Inventory every installed unit
| Field | Record | Why it matters |
|---|---|---|
| Identity | Room, floor, serial number, generation, battery or hardwired version, manufacture date, installation date, replacement date, and owner | Prevents one healthy app tile from hiding an expired, missing, wrong-room, or unowned unit |
| Physical state | Mount, vents, dust, paint, damage, obstruction, distance from cooking or steam, environmental limits, power, backup batteries, and indicator state | Smart features cannot correct a bad physical location, contamination, blocked vents, failed power, or expired sensor |
| Warning and interconnect | Voice name, horn reach, room-to-room warning, wireless interconnect, accessibility plan, household response, and local test result | Every required occupant must receive and understand the warning without depending on one phone |
| Digital state | Nest or Google Home household, owners, shared users, Wi-Fi, software, notifications, recovery method, old sessions, and removed-user proof | Stops account loss or former users from becoming a hidden support and privacy problem |
| Replacement path | Applicable local code, exact replacement model, battery or hardwired format, mount or adapter, interconnect compatibility, installer, disposal, and acceptance test | A compatible app claim does not prove physical, electrical, code, or whole-home compatibility |
Check placement, code, and life-safety boundaries
Use the current local authority, fire service, building code, product instructions, and licensed professional where required. Do not use a general online placement diagram as approval for a specific home. Record sleeping areas, bedrooms, every level, hallways, stairs, kitchens, fuel-burning appliances, attached garages, ceiling form, airflow, doors, accessibility needs, occupants, pets, and evacuation routes.
Smoke and CO alarms do not detect every hazard. They do not replace a combustible-gas detector, heat detector, sprinkler, fire extinguisher, safe cooking practice, appliance service, chimney work, ventilation, electrical repair, evacuation plan, or emergency response where those jobs are required.
Test local warning before app features
- Read the official test and safety instructions for the exact generation and power version. Use the manufacturer’s approved test method; do not expose the unit to smoke, flame, exhaust, or improvised chemicals.
- Confirm the named unit responds locally with the expected horn, voice, light, status, and room name.
- Confirm every compatible interconnected unit responds as documented. Test from sleeping, living, detached, loud, closed-door, and accessible areas under safe conditions.
- Record app status and notification delivery separately. A successful push notification does not pass the local warning test, and a failed push does not prove the local detector failed.
- Exit test mode cleanly, confirm normal status, resolve every fault, and record the next test and replacement dates.
Prove internet, power, account, and owner failures
| Failure | Record | Pass condition |
|---|---|---|
| Internet unavailable | Local detection, horn, voice, interconnect, app status, push notification, history, reconnect, clock, and missed-event boundary | Required local detection and warning remain; lost remote jobs are explicit and restore cleanly |
| Building power lost | Hardwired state, backup batteries, battery-only units, warning, interconnect, trouble, app status, restoration, and battery replacement | Each unit behaves according to its documented power design and reports trouble or recovery correctly |
| Wi-Fi or router changes | Local warning, interconnect, app control, notification, household ownership, setup route, reconnect, and old-network removal | Life-safety functions remain and approved digital functions return without creating an unknown owner |
| Primary account owner unavailable | Second household manager, physical access, tests, app status, support, Wi-Fi, replacement record, bills, and account recovery | A second authorized person can identify every unit, test it, resolve a fault, and start replacement |
| One unit expires or fails | Location, warning, app state, interconnect effect, temporary protection approved by the responsible authority, replacement model, installation, and retest | The failed unit is not ignored or silently removed; the approved replacement restores the complete design |
Plan Nest Protect replacement before expiry
Start before the printed replacement date. A whole-home replacement may involve several manufacture dates, power versions, mounts, circuits, rooms, wireless links, accounts, and accessibility needs. Do not replace only the first unit that chirps and forget the rest.
- Export the inventory and sort by replacement date.
- Confirm current local placement, power, interconnect, certification, permit, and installer requirements.
- Compare the exact replacement model. For US owners considering the SC5, read First Alert’s current product and support records, then verify battery versus hardwired format and compatibility for the actual home.
- Record what happens to Nest or Google Home rooms, household access, automations, notifications, old devices, data, and account recovery.
- Install through the approved route, remove and dispose of old units correctly, then run the complete local warning, interconnect, app, outage, user, and second-owner acceptance test.
Nest Protect and a security system solve different jobs
Nest Protect is a life-safety alarm, not a burglar-alarm panel or central-station monitoring certificate. A security system may add direct door and window zones, intrusion warning, communications, professional monitoring, panic, camera evidence, access control, and a household response plan. Keep the records separate.
Abode’s Smoke Alarm Monitor listens for supported smoke and CO alarm sound patterns as part of an Abode system. It does not detect smoke or CO itself and does not replace required certified alarms. Compare the exact detector, listener, hub, warning, communications, monitoring plan, placement, sound compatibility, outage state, and passed test.
Use the smart-home security device guide to keep life safety, intrusion sensing, cameras, locks, and automations in their proper roles. Use the no-monthly-fee guide only after writing who receives and acts on each alarm when no monitoring service exists.
45-minute Nest Protect owner acceptance test
- Reconcile every unit against room, floor, serial number, generation, power version, manufacture date, replacement date, mount, household, owner, software, and code record.
- Use the official approved test route on each unit. Confirm local horn, voice, light, room name, interconnect, accessibility, household response, normal exit, and next-test date.
- Record app status and notification delivery separately. Remove one former or temporary user and prove old household, app, invitation, device, and recovery access fail.
- Run safe documented internet, router, and power-loss checks. Record local warning, interconnect, digital limits, trouble, reconnect, and restoration.
- Give the inventory and replacement plan to a second authorized person. Have that person identify the next expiring unit, run an approved test, find support, and explain the replacement route without the primary phone.
Nest Protect FAQ
Is Nest Protect still for sale?
No through Google’s current route. Google says Nest Protect is no longer available for sale but remains supported. Existing owners should use current support guidance and plan replacement by manufacture date.
When must a second-generation Nest Protect be replaced?
Google says 10 years after the manufacture date. Check the printed date and device status for every unit rather than counting from installation.
What replaces Nest Protect in the US?
Google directs US customers to the compatible First Alert SC5. Verify the exact battery or hardwired model, local code, mount, interconnect, app, household, and whole-home test before purchase.
Does Nest Protect work when Wi-Fi is down?
Google says compatible Protect units use their own wireless interconnect and can continue talking to each other if Wi-Fi is down. App and remote functions have separate network dependencies, so test and record both paths.
Can Nest Protect replace a monitored security system?
No. Smoke and CO detection, local life-safety warning, intrusion sensors, camera evidence, alarm communications, central-station receipt, emergency calling, and dispatch are separate jobs.
William is a tech buff and former corporate security officer turned cybercrime analyst. Computers have few secrets left for him, but home security and alarm systems… Well, those have plenty of secrets for their users, which William is now uncovering and explaining. His articles on home security helped many people take the matter seriously, invest in highly performing systems, and avoid becoming victims of burglaries.
Timothy M. says
This is one of those products you buy and completely forget about. I assume mine is still working but I have never heard it go off or anything. I don’t think you need to be ‘hip’ or ‘cool’ with monitoring / smart phone app connection when it’s just a sensor. Now that Nest is coming out with other products I can see myself adding the whole product line into my home and paying a fee if needed but then again it will be new and buggy so might be best to let them test it a few years.