Shelly Plus Smoke Alarm

Shelly Plus Smoke Alarm

4.4
514 ratings

Model: SNSN-0031Z

25% OFF
€53.43
€39.95
As an Amazon Associate I earn from qualifying purchases
Open selection
Our review

Shelly Plus Smoke Alarm Review: A No-Hub WiFi Smoke Detector Built for Tinkerers

Fast, hub-free WiFi setup and deep Home Assistant/MQTT automation, with no CO detection and no Apple Home support.

The verdict

The Shelly Plus Smoke Alarm is a WiFi-connected smoke detector aimed squarely at smart home enthusiasts already running Shelly, Home Assistant, or MQTT-based setups. Buyers consistently praise how quickly it pairs over WiFi without needing a separate hub and how well it plugs into automations, while a smaller group reports frustrating false alarms over time. It nails simple smartphone alerts and a long battery life, but its lack of carbon monoxide detection and Apple HomeKit support means dedicated Apple households or anyone wanting combined smoke and CO coverage should look elsewhere.

Best for
  • Home Assistant and MQTT users
  • Existing Shelly ecosystem owners
  • Google Home and Alexa households
  • Buyers who want hub-free WiFi setup

Pros

  • Hub-free setup over 2.4GHz WiFi
  • Strong Home Assistant, MQTT, Google Home and Alexa integration
  • Loud built-in siren and built-in light
  • Long rated battery life (5 years)
  • 3-year warranty

Cons

  • No CO sensor or CO alerts
  • No Apple HomeKit or Matter support
  • No automatic self-testing
  • Short initial pairing window reported by some buyers

Who is the Shelly Plus Smoke Alarm for?

This is a battery-powered, WiFi-only smoke alarm built for people who already have a smart home running on Home Assistant, MQTT, or other Shelly devices, since it needs no hub or bridge to get online. Reviewers repeatedly mention integrating it into Home Assistant and Loxone setups for push notifications and scene triggers, and several buyers say they added it because they were already happy with other Shelly gear around the house. It also works with Google Home, Alexa, and Samsung SmartThings, so most non-Apple smart home households can bring it into their existing automations.

What buyers love

The most common praise is how fast and simple setup is: buyers describe pairing the alarm to WiFi and their phone app in minutes with no additional hardware, matching the product's hub-free 2.4GHz WiFi design. The built-in siren rated over 85dB and instant push notifications when smoke is detected come up often, with more than one reviewer describing being alerted to burnt food or a real smoke event through the app while away from home. The rated 5-year battery life is called out as a real advantage since it removes the hassle of frequent battery swaps, and tinkerers specifically highlight MQTT support for wiring the alarm into third-party systems like Loxone.

What to know before you buy

The alarm has no CO sensor and no CO alerts, so households that want combined smoke and carbon monoxide protection will need a separate detector or a different model entirely. It also has no Apple HomeKit or Matter support, ruling it out for Apple-first smart homes, and it lacks a self-test feature, so owners need to test it manually rather than relying on automatic diagnostics. A few buyers report a narrow window (just a few minutes) to complete initial pairing before needing to restart the process, which can be fiddly when setting up several units at once. A small minority of reviewers reported repeated false alarms after months of otherwise reliable use, so while most owners find it dependable, it is worth keeping an eye on performance over time and following Shelly's placement guidance to minimize false triggers.

Is the Shelly Plus Smoke Alarm worth it?

For its price tier, the Shelly Plus Smoke Alarm packs in a loud built-in siren, a built-in light, automations support, and a 3-year warranty, all wrapped in a compact, unobtrusive design that reviewers say blends into a ceiling easily. Feedback is largely positive and skews toward buyers who value smart home flexibility over a feature checklist, making this a strong pick for automation-minded households, while anyone prioritizing CO detection or Apple ecosystem support should weigh a different model.

Frequently asked questions

Does the Shelly Plus Smoke Alarm detect carbon monoxide?

No. It is a smoke-only alarm with fire alerts and low-battery alerts, but it has no CO sensor and no CO alerts, so a separate CO detector is needed for that coverage.

Does it work with Apple HomeKit?

No, it does not support Apple HomeKit or Matter. It does integrate with Google Home, Amazon Alexa, Samsung SmartThings, and Home Assistant.

Do I need a hub to set it up?

No hub is required. It connects directly over 2.4GHz WiFi and pairs with the Shelly app, which buyers consistently describe as fast and straightforward.

How long does the battery last?

It is rated for about 5 years on its CR123A battery, and it sends low-battery alerts through the app so you know before it needs replacing.

Can it trigger other smart home automations?

Yes. It supports automations and is popular with Home Assistant and MQTT users for triggering scenes, notifications, and other devices when smoke is detected.

At a glance

Summary

Everything this smoke & co detector supports, grouped by category.

Size & Materials
3.4 × 3.5 × 1.2 in (86 × 88 × 31 mm)3.4 oz (95 g)
Connectivity
2.4 GHz WiFiBluetooth (For Pairing)
Integrations
Google HomeAlexaSamsung SmartThingsHome Assistant
Sensors
Smoke
Alerts
Fire AlertsLow Battery Alerts
Features
Built-in SirenBuilt-in Light

Price History

Loading price history...

Company
Shelly logo

Shelly

4.4/ 5 avg ratingBulgaria flagHeadquartered in Bulgaria

Shelly, based in Bulgaria, makes compact smart relays, switches, plugs and sensors that fit behind existing wall switches and outlets to automate almost any home wiring. Its devices are popular with advanced users for offering local control, a built-in web interface, MQTT and broad integration with Home Assistant, Alexa and Google Home. Shelly is a favorite for retrofitting smart control without replacing fixtures.

Full specifications

Every spec, organized

Browse the full breakdown by category. Tap the on any row for what it means, or the for sources and documentation.

Size & Materials

Dimensions

3.4 × 3.5 × 1.2 in (86 × 88 × 31 mm)

Weight

3.4 oz (95 g)

Power

Wired

NO

Battery Type

CR123A

Battery Life

5 years

Connectivity

2.4 GHz WiFi

YES

5 GHz WiFi

NO

Bluetooth

For Pairing

Zigbee

NO

Z-Wave

NO

Thread Protocol

NO

Integrations

Google Home

YES

Alexa

YES

Apple HomeKit

NO

Samsung SmartThings

YES

Home Assistant

YES

IFTTT

NO

Matter

NO

Display

Screen

NO

Screen Type

-

Sensors

Smoke

YES

CO

NO

Occupancy

NO

Temperature

NO

Humidity

NO

Air Quality

NO

Ambient Light

NO

Motion

NO

Alerts

Fire Alerts

YES

CO Alerts

NO

Low Battery Alerts

YES

Temperature Alerts

NO

Air Quality Alerts

NO

Features

Built-in Siren

YES

>85db

Built-in Light

YES

Tests Itself

NO

Pathlight

NO

Steam Check

NO

Automations

YES

More Smoke & CO Detectors

Compare these next

View all
Shelly

More from Shelly

View all
Stay in the loop

Smart Home Deals & News straight to your inbox

Join the newsletter and get the best smart home deals and new releases in your inbox.

Your subscription could not be saved. Please try again.
Your subscription has been successful.

Smart Home Deals & News straight to your inbox

Join the newsletter and get the best smart home deals and new releases in your inbox.