Smoke alarms are one of the smart home categories where surprisingly little has changed in recent years, even though this is exactly where a link to your own system makes the most sense. Chinese manufacturer Heiman is changing that with the S1-TM. The smoke alarm uses Matter over Thread, so it joins Apple Home, Google Home, SmartThings or Home Assistant without a manufacturer bridge, and it reports temperature and humidity on top. It is available on Amazon, including Amazon UK.
Three sensors in one device
The real highlight of the S1-TM is that it measures temperature and humidity as well as detecting smoke. One ceiling-mounted device covers three jobs, with no extra sensors on the wall or ceiling.
Because the alarm connects via Matter, the readings are available outside Heiman’s own ecosystem too. You can use them for automations that react to certain temperature or humidity levels, independently of the smoke alarm itself.
Matter over Thread instead of a closed system
For the S1-TM to show up in Apple Home, Google Home, Samsung SmartThings or Home Assistant, all you need is a Thread border router in your home. In the Apple world, that could be a HomePod mini, a current HomePod or an Apple TV 4K with Thread support. Google and Amazon homes can use a Nest Hub (2nd gen) or an Echo (4th gen), for example.
Once it’s set up, the smoke alarm works in automations like any other Matter device. If smoke is detected, you could switch on every light in the house, raise the blinds or turn off smart plugs automatically.
Dual-wavelength sensor against false alarms
On the technical side, the S1-TM uses an optical dual-wavelength sensor (red light plus infrared). According to Heiman, it tells real fire smoke apart from cooking fumes or steam more reliably than classic single sensors. In kitchens and bathrooms in particular, that cuts down on nuisance alarms, a long-running annoyance with many smoke alarms.
A 360-degree smoke inlet is designed to remove the classic detection blind spot, according to the manufacturer. Automatic self-monitoring warns you proactively about sensor or battery problems.
Compact, magnetic mount, replaceable battery
At 70 mm across and 37 mm high, the S1-TM is fairly compact. It attaches to a magnetic mounting plate that you can either screw or stick in place, with no tools and in around 30 seconds. That makes it a good fit for rented homes, too.
It runs on a replaceable CR123A lithium battery. Heiman’s spec sheet rates it for around 3.5 years, while the Amazon UK listing quotes up to five years. The sensor itself is designed to last ten years, which is standard for smoke alarms.
When the alarm goes off, a flashing red LED backs up the 85 dB siren, and you get a push notification through your Matter app, even when you’re not at home.
Specifications at a glance
- Type: photoelectric smoke alarm with temperature and humidity sensor
- Smart home: Matter over Thread, no hub from Heiman needed (Thread border router required); works with Apple Home, Google Home, Amazon Alexa (via Matter), Samsung SmartThings, Home Assistant and Homey
- Sensor: optical dual-wavelength sensor (red light + infrared), 360° smoke inlet
- Alarm: ≥85 dB (at 3 m), flashing red LED
- Dimensions: Ø 70 × 37 mm
- Battery: replaceable CR123A lithium battery, around 3.5 years according to Heiman
- Sensor lifespan: 10 years
- Mounting: magnetic mounting plate, screw or adhesive fixing
- Certification: EN 14604, Matter, CE, UKCA
- Wireless range: up to around 60 m in open space
Availability and how it compares
The Heiman S1-TM is available on Amazon, and in the UK it is sold by Heiman’s official UK store. The Amazon box below shows the current price.
It joins a still fairly small group of genuine Matter-over-Thread smoke alarms. Heiman already offered the simpler HS1SA-M without climate sensors. In the US and Canada, the S1-TM is sold as a separate version certified to UL 217.
Early owner reports are positive about pairing with Apple Home and Home Assistant, where the S1-TM shows up as separate smoke, temperature and humidity sensors. One UK owner reports that Alexa does not show the humidity reading yet when the alarm is shared via Matter.
If you already run a Thread border router and want your smoke alarms in your smart home rather than in a closed system, the S1-TM gives you a device that doubles as a temperature and humidity sensor. That is handy in hallways, bedrooms or basements, where you would otherwise need a separate climate sensor.
Verdict
With the S1-TM, Heiman shows that even a device every home needs, the smoke alarm, can fit neatly into the Matter ecosystem without compromising on its core job. The extra climate data is a nice bonus that can make separate sensors elsewhere unnecessary.
If you already use Matter over Thread, this is an understated but well thought-out addition to your smart home, as long as a Thread border router is already in place. You can find more models in our smoke alarm overview and on the Heiman S1-TM product page.
Last updated on 2026-11-14 / affiliate links / images from the Amazon Product Advertising API. Prices shown may have changed since then. All information without guarantee. * = affiliate link: if you order a product through such a link, we receive a commission from the seller. There are no extra costs for you.
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