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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.
In 2025, the two clearest leaders in smart smoke detection are Google's Nest Protect and First Alert's Onelink range. 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.
🥇 Google Nest Protect — Best Overall
The Nest Protect is the benchmark for smart smoke detection. It detects both smoke and carbon monoxide, uses a split-spectrum sensor for superior false alarm reduction, and speaks to you in a calm voice to tell you exactly what it has detected and where. The Pathlight feature doubles as a night light, glowing gently when you walk past at night.
Google Nest Protect (2nd Gen)
Smoke + CO detection · Split-spectrum sensor · Voice alerts · App notifications · Works with Google Home · Wired and battery versions
Check Price on AmazonMultiple Nest Protects interconnect wirelessly. If the kitchen detector triggers, every Protect in your home will announce "There is smoke in the Kitchen" — telling your family exactly where the danger is and where not to go. This is a critical safety advantage over traditional systems that simply beep.
Nest Protect Features
- Split-spectrum smoke sensor with CO detection
- Steam Check to reduce false alarms from showers
- Heads Up warning before full alarm (early smoke detection)
- Self-testing capability via app
- Works with Google Home for automation triggers
- 10-year sensor lifespan
Limitations
- Premium price — expect to pay 3–4x a standard detector
- Google ecosystem-centric (limited Apple HomeKit)
- Requires Nest app — not compatible with Matter yet
🥈 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.
First Alert Onelink Safe & Sound
Smoke + CO detection · Built-in Alexa speaker · Apple HomeKit support · App alerts · Wireless interconnect
Check Price on AmazonThe 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
| Feature | Nest Protect | First Alert Onelink |
|---|---|---|
| Smoke + CO Detection | Yes | Yes |
| Apple HomeKit | No | Yes |
| Google Home | Yes | No |
| Voice Alerts (room location) | Yes | Yes |
| Built-in Smart Speaker | No | Alexa |
| Wireless Interconnect | Yes | Yes |
| Night Light | Yes (Pathlight) | No |
| False Alarm Reduction | Split-spectrum | Standard |
Buying Guide
Wired vs Battery
Both Nest Protect 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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