The frient Intelligent Heat Alarm (HESZB-120) is a Zigbee 3.0 battery-powered heat alarm with a built-in 85 dB siren and integrated temperature sensor.
The device monitors and analyses rapid increases in room temperature. It is particularly suitable for indoor locations where cooking fumes, steam, dust, or fireplaces may cause frequent false alarms with optical smoke detectors. The built-in siren continues to operate locally even if the Zigbee network or internet connection is unavailable.
The integrated temperature sensor measures temperatures between 0 and +50 °C with a resolution of 0.1 °C. The measured temperature and fire alarm status can also be used within a smart home system through a compatible Zigbee hub. The system can send remote notifications when an alarm occurs and trigger other devices, such as turning on lights or activating additional compatible sirens.
The Intelligent Heat Alarm is powered by a single replaceable CR123A lithium battery. According to the manufacturer, the expected battery life is approximately five years with temperature reporting every five minutes. The device operates as a Zigbee end device and therefore does not relay data for other Zigbee devices within the mesh network.
About frient
frient is a Denmark-based company that develops and manufactures Zigbee-based smart home devices. Its product range includes door and window sensors, motion sensors, temperature and humidity sensors, air quality sensors, water leak detectors, vibration sensors, smoke and heat alarms, smart plugs, energy meters, and other smart home accessories.
frient products use the standard Zigbee 3.0 protocol, making them compatible with a wide range of Zigbee gateways. They are supported by Home Assistant, Zigbee2MQTT, ZHA, SmartThings, Homey, and many other Zigbee-based systems. Available features may vary depending on the gateway and device support.
Key Product Features
- Heat-based fire detection: Detects rapid increases in temperature, making it less susceptible to smoke, dust, or steam than an optical smoke detector.
- Local audible alarm: When fire is detected, the built-in siren produces an 85 dB alarm at a distance of 3 metres.
- Temperature measurement: The integrated sensor measures ambient temperature between 0 and +50 °C.
- Remote alarm status: Fire alarm events can be reported to a compatible Zigbee smart home system.
- Automation support: Alarm status and measured temperature can be used as automation triggers.
- Battery monitoring: Reports battery level and low battery status.
- Replaceable battery: Powered by one standard CR123A lithium battery.
- Zigbee 3.0 communication: Uses low-power wireless communication with compatible Zigbee gateways.
- Compact design: The 65 mm diameter enclosure is designed for ceiling installation.
Smart Home Protocols and Platform Compatibility
- Zigbee 3.0: Requires a compatible Zigbee gateway or coordinator. The device operates as a Zigbee end device.
- Home Assistant: Can be integrated into a local system using a compatible Zigbee coordinator. Alarm status, temperature, and battery information can be used in automations.
- Zigbee2MQTT: Supported as the Develco HESZB-120 hardware variant. Alarm status, test status, temperature, battery level, and battery voltage are available.
- MQTT integration: When using Zigbee2MQTT, sensor and status data can be published through MQTT. The MQTT connection is provided by Zigbee2MQTT.
- ZHA: Compatible with standard Zigbee coordinators. Available entities and siren control depend on current ZHA device support.
- Samsung SmartThings: Can be integrated using a compatible SmartThings hub and the appropriate Edge Driver.
- Homey: Alarm and temperature data can be used in automations through Homey systems supporting frient devices.
- Offline operation: When used with Home Assistant, Zigbee2MQTT, or ZHA together with a local Zigbee coordinator, data can be processed without an internet connection.
Smart Features
- Fire alarm status: Sends an alarm event to the connected Zigbee system when heat-based fire detection is triggered.
- Remote notifications: The selected smart home platform can send mobile notifications when an alarm occurs.
- Real-time temperature: Displays the measured ambient temperature in the connected smart home system.
- Temperature-based automations: Measured temperature can trigger ventilation, cooling, or additional alarm procedures.
- Fire alarm automations: Compatible sirens, lighting, and notification workflows can be activated automatically.
- Remote siren activation: In supported Zigbee2MQTT integrations, the built-in siren can be activated manually or through automations.
- Siren duration: In Zigbee2MQTT, manually triggered alarm duration can be configured between 0 and 600 seconds.
- Self-test status: Device self-tests can be reported as a separate status to compatible systems.
- Fault indication: Supported integrations can report sensor faults or unreliable operating conditions.
- Battery level: Remaining battery capacity can be displayed as a percentage.
- Low battery warning: Battery replacement can be used as a dedicated alarm condition.
- Battery voltage: Zigbee2MQTT can report battery voltage in millivolts.
- OTA firmware updates: Supports wireless firmware updates through Zigbee2MQTT.
Technical Specifications
- Product name: Intelligent Heat Alarm
- Hardware model: HESZB-120
- Product type: Zigbee heat alarm
- Wireless protocol: Zigbee 3.0
- Zigbee device type: End device
- Power supply: 1 × replaceable CR123A lithium battery
- Expected battery life: Approximately 5 years with temperature reporting every 5 minutes
- Battery monitoring: Battery level and low battery reporting
- Radio sensitivity: -92 dBm
- Radio transmit power: Typically +4 dBm
- Wireless range: At least 100 m in open space
- Fire detection: Heat-based detection
- Siren output: 85 dB at 3 m
- Temperature measurement range: 0 to +50 °C
- Temperature resolution: 0.1 °C
- Temperature accuracy: Typically ±0.5 °C, maximum ±2 °C
- Sampling interval: Configurable between 2 and 65,000 seconds
- Temperature reporting: Configurable
- Protection rating: IP20
- Operating temperature: 0 °C to +50 °C
- Operating humidity: Up to 95% RH, non-condensing
- Dimensions: Ø 65 × 40 mm
- Colour: White
- Compliance: CE, RoHS, and REACH
- Applicable standards: EN 54-5 and DIN 14676
- Certification: Zigbee 3.0
