Google Nest Protect alarm signals: beeps, chirps and lights
Nest Protect (smoke and CO in one) talks: a light ring changes colour and the alarm says what it has found and in which room. Yellow is a Heads-Up or a problem, red is an emergency, green is all well. Chirps are kept for batteries, sensor failure and expiry.
If it is sounding a full alarm: the maker’s emergency instruction
Smoke alarm
Google (Nest Protect): at an emergency smoke level Protect sounds a continuous alarm and says “Emergency”. Get out of the house immediately: follow your evacuation plan, alert small children and anyone who needs help, feel doors with the back of your hand before opening them, close doors behind you, meet at your meeting place, count heads and call the fire department; do not re-enter unless a fire official says it is safe.
From What to do if Nest Protect detects smoke in your home — Google Nest Help and Nest Protect lights and sounds — Google Nest Help.
Carbon monoxide alarm
Google (Nest Protect): when CO reaches emergency level Protect says “Emergency. There’s carbon monoxide in the (room). Move to fresh air.” Press the centre button to silence or reset Protect, call your fire department or 911, move everyone to fresh air, and do not re-enter until the emergency services tell you to.
Every Google Nest Protect signal we could source
| What you see | What you hear | What it means |
|---|---|---|
| Red light | Says: “Emergency. There’s smoke in the (room name).” | Real alarm: Smoke in the room has reached emergency level. |
| Red light | Says: “Emergency. There’s carbon monoxide in the (room name). Move to fresh air.” | Real alarm: Carbon monoxide in the room has reached emergency level. |
| Yellow or amber light | Says: “Heads-Up. There’s smoke in the (room name). The alarm may sound.” | Early warning: An early warning: smoke levels are rising but are not yet at alarm level. |
| Yellow or amber light | Says: “Heads-Up. There’s carbon monoxide in the (room name). The alarm may sound.” | Early warning: An early warning: carbon monoxide levels are rising. |
| Yellow or amber light | Says: “Smoke alarm silenced. / Carbon monoxide alarm silenced.” | Hush or silence mode: You have silenced the alarm or Heads-Up for now. |
| Green light | Says: “The smoke alarm is over in the (room name). / The carbon monoxide alarm is over in the (room name).” | Normal operation: Smoke or CO levels are falling and conditions are returning to normal. |
| One green flash | Silent | Normal operation: Nightly Promise: Protect has checked its sensors, batteries and Wi-Fi and everything is working. |
| Yellow or amber light | Says: “The batteries are low in the (room name). Replace the batteries soon.” | Low battery: The batteries (or a wired Protect’s back-up batteries) will need replacing in the coming months. |
| Yellow or amber light | One chirp about every 60 seconds | Low battery: Only a few days of battery life are left; Protect chirps day and night until the batteries are replaced. |
| Yellow or amber light | One chirp about every 60 seconds | Fault: Protect has tested a sensor and found a problem. |
| Yellow or amber light | Two chirps about every 60 seconds | End of life: Protect has reached the end of its life under safety regulations. |
| Yellow or amber light | Says: “Nest Protect is offline in the (room name).” | Fault: Protect is no longer connected to the internet, so alerts will not reach your phone. |
| Blue light | Says: “Hi. / Press to test.” | Normal operation: Setup, or a test you started: after a press of the centre button, Protect pulses blue while it tests its sensors, batteries, Wi-Fi and link to other Protects, then tells you the result. |
Sources
Google Nest Protect’s own documents only, read on the date shown.
- Google: Nest Protect lights and sounds — Google Nest Help — Nest Protect (1st and 2nd gen, battery and wired). support.google.com Checked 2026-09-29.
- Google: What to do if Nest Protect detects smoke in your home — Google Nest Help — Nest Protect. support.google.com Checked 2026-09-29.