Best Smart Smoke Detectors in 2026

Smoke detectors save lives — but a traditional detector sitting on your ceiling is a passive device that only screams when there's a problem. A smart smoke detector does so much more: it sends alerts to your phone the moment it detects smoke or carbon monoxide, tells you which room triggered the alarm, and can even integrate with your smart home to trigger lights, unlock doors, or call emergency services.

Google stopped making the Nest Protect in March 2025 and now points buyers to the First Alert SC5, which was designed to work with Google Home and with existing Nest Protects. That leaves First Alert covering both camps: the SC5 for Google Home households and the Onelink range for Apple and Alexa users. Both are significantly better than a standard £15 detector, but they target slightly different users. Here's everything you need to know.

Why Upgrade to a Smart Smoke Detector?

The core advantage of a smart smoke detector is notification when you're not home. A traditional alarm only alerts people who can physically hear it — great when you're in the house, useless when you're at work or on holiday. A smart detector sends a push notification to your phone immediately, allowing you to call a neighbour, check a camera, or contact emergency services.

Beyond remote alerts, smart detectors typically offer: battery status monitoring (no more "chirp" surprises at 3 AM), interconnection with other smart detectors in the home, and for advanced users, integration with smart home platforms to trigger automations when an alarm fires.

First Alert SC5 — Best Overall (the Nest Protect Replacement)

When Google ended Nest Protect production in March 2025, it named First Alert's SC5 Smart Smoke & Carbon Monoxide Alarm as the replacement for Google Home users. The SC5 detects both smoke and CO, gives spoken alerts that announce the type of hazard and the room it's in, and issues a "Heads-Up" warning before a full alarm, much like the Protect did. It comes in a battery version with a sealed 10-year battery and a hardwired version with battery backup; First Alert lists both at $129.99.

SC5 alarms interconnect over Wi-Fi, and once added to the Google Home app they also interconnect with any Nest Protects you already own, so a mixed home still announces where an alarm started. You set the alarm up in the First Alert app first, then import it into Google Home. Tom's Guide made the SC5 its top smart smoke detector pick, while noting it is "by no means perfect"; owner reviews on retailer sites are more mixed on Wi-Fi connectivity.

SC5 Features

• Combined smoke and CO detection (First Alert's Precision Detection, aimed at fewer nuisance alarms)
• Voice alerts that name the hazard and its location
• Heads-Up warning before full alarm
• Wi-Fi interconnect with other SC5s and with existing Nest Protects
• Works with Google Home and the First Alert app
• 10-year lifespan; battery model uses a sealed 10-year battery

Limitations

• Premium price — around $130 each, several times a standard detector
• Google Home and the First Alert app only: no Matter, no Apple HomeKit
• 2.4 GHz Wi-Fi only

First Alert Onelink — Best for Apple HomeKit

The First Alert Onelink Safe & Sound is a compelling alternative for Apple households. It combines smoke and CO detection with a built-in Amazon Alexa speaker — making it a multi-functional ceiling device. More importantly for Apple users, it supports Apple HomeKit natively, enabling Siri voice control and Homekit automation triggers.

The Onelink's killer feature is the built-in smart speaker. It functions as a full Amazon Alexa device — you can ask questions, play music, and control other smart home devices through it. This is either a nifty bonus or a privacy concern depending on your perspective, but it's certainly distinctive.

Onelink Features

• Smoke + CO detection with voice alerts
• Native Apple HomeKit support
• Built-in Amazon Alexa speaker
• Wireless interconnect with other Onelink detectors
• Ambient temperature display in app
• Works with Amazon Alexa routines

Comparison Table

Buying Guide

Wired vs Battery

Both the SC5 and Onelink are available in wired (hardwired into ceiling) and battery versions. Wired versions are more reliable and don't require battery changes, but require an electrician to install if you don't already have wiring. Battery versions are self-contained and install in minutes.

How Many Do You Need?

UK building regulations recommend a detector in every room where a fire could start (kitchen, living room) and in the hallways on every floor. For full protection, most 3-bedroom homes need 4–6 detectors. The interconnect feature means they all trigger together, so start with critical locations and expand over time.

CO Detection — Is It Necessary?

Absolutely, especially if you have gas appliances, an oil boiler, or an attached garage. Carbon monoxide is odourless and colourless — without a detector, CO poisoning gives no warning. Choose a combined smoke/CO detector rather than separate devices wherever possible.

Placement Advice

Smoke rises, so ceiling mounting or high on a wall (within 30 cm of ceiling) is ideal. Keep detectors at least 30 cm away from light fittings and corners where airflow is poor. In kitchens, maintain at least 3 metres from cooking appliances to reduce cooking-related false alarms — or use a detector specifically designed for kitchens.

CO detectors should be positioned at chest height (not ceiling height, as CO is roughly the same density as air). Combined smoke/CO detectors placed on the ceiling as a compromise — they'll catch both, but a dedicated CO detector at chest height in a room with gas appliances is the gold standard.

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