frient HESZB-120 Zigbee Heat Alarm

Detect Dangerous Heat Without Relying on Smoke Detection

What is the frient HESZB-120 Zigbee Heat Alarm?

The frient HESZB-120 Zigbee Heat Alarm is a battery-powered smart fire detector designed to detect dangerous increases in heat rather than smoke. It features an integrated 85 dB siren, built-in temperature monitoring and Zigbee 3.0 connectivity for remote alerts and smart-home integration through a compatible Zigbee gateway.

Unlike a traditional smoke detector, the HESZB-120 is designed for areas where smoke, steam or dust may cause unwanted smoke-alarm activations. Reichelt lists the detector as heat-based with an alarm threshold above approximately 57°C, making it particularly useful in kitchens, near fireplaces and in dusty indoor areas where a conventional smoke alarm may be less suitable.

Key Takeaways

• Heat-based fire detection
• Alarm threshold above approximately 57°C
• Zigbee 3.0 connectivity
• 85 dB siren at 3 meters
• Built-in temperature sensor
• Temperature range from 0°C to 50°C
• Replaceable CR123A battery
• Approximately 5-year battery life
• Low-battery reporting
• Zigbee2MQTT support
• Home Assistant integration through supported Zigbee software
• Minimum 100 m open-field Zigbee range
• IP20 indoor rating
• EN54-5 and DIN 14676 compliant
• Zigbee 3.0 certified

Heat Detection for Areas Where Smoke Alarms Can Be Problematic

Smoke detectors are essential in appropriate locations, but some indoor environments can produce steam, dust or cooking smoke that may cause unwanted alerts.

The frient Intelligent Heat Alarm HESZB-120 is designed to respond to heat instead of smoke. frient specifically positions it for areas such as kitchens, rooms with fireplaces and dusty indoor environments where smoke-based sensing may not be ideal.

When dangerous heat is detected, the alarm activates its built-in siren locally. If the detector is connected to a compatible Zigbee gateway, the event can also be reported to your smart-home platform for remote notification.

This makes the HESZB-120 useful for:

• Kitchens
• Rooms with fireplaces
• Utility rooms
• Indoor workshops
• Dusty storage areas
• Garages within the specified environmental conditions
• Home Assistant installations
• Zigbee smart homes

The local audible alarm remains the primary warning mechanism. Connected notifications provide an additional layer of monitoring when supported by your smart-home system.

Why Choose the frient HESZB-120?

Heat-Based Fire Detection

The HESZB-120 detects heat rather than smoke.

Reichelt specifies heat-based fire detection at above 57°C, while frient describes the detector as responding to rapidly increasing levels of heat rather than ordinary smoke or dust.

This makes the detector useful in locations where a conventional smoke alarm may be prone to nuisance alerts.

85 dB Local Siren

The integrated siren produces 85 dB at 3 meters.

When the detector identifies a fire-related heat condition, occupants receive an immediate audible warning without relying on a phone, internet service or external speaker.

Smart notifications should be treated as supplementary alerts rather than a replacement for the local siren.

Zigbee 3.0 Connectivity

The frient Heat Alarm uses Zigbee 3.0 and operates as a Zigbee end device.

A compatible Zigbee hub or coordinator enables connected features such as:

• Fire-event reporting
• Temperature monitoring
• Battery status
• Low-battery alerts
• Smart-home notifications

Because the detector is battery powered, it does not function as a Zigbee mesh router.

Built-In Temperature Sensor

The HESZB-120 also measures ambient temperature.

frient specifies:

• Temperature range: 0°C to 50°C
• Resolution: 0.1°C
• Typical accuracy: ±0.5°C
• Maximum stated accuracy deviation: ±2°C

The reporting interval can be configured by supported systems, making the sensor useful for general environmental monitoring in addition to its fire-alarm role.

Possible uses include:

• Room temperature dashboards
• Heating automations
• High-temperature notifications
• Home Assistant monitoring
• Historical temperature tracking

The built-in temperature reading is an additional smart-home feature and does not replace any separate temperature-safety equipment required by local regulations.

Home Assistant and Zigbee2MQTT

The HESZB-120 is supported by Zigbee2MQTT.

Zigbee2MQTT currently documents the HESZB-120 hardware family and exposes:

• Alarm state
• Battery percentage
• Battery voltage
• Low-battery state
• Test state
• Temperature
• Fault state
• Reliability state
• Siren control
• Maximum siren duration

frient versions are recognized as white-label variants of the same Develco hardware platform.

This makes the HESZB-120 particularly useful for Home Assistant users who want fire-alarm status and temperature data available alongside other Zigbee devices.

Smart Notification Support

When connected to a compatible Zigbee gateway or automation platform, the Heat Alarm can be used to trigger remote notifications.

Possible alerts include:

• High-temperature alarm
• Fire alarm notification
• Battery warning
• Fault notification
• Test-state reporting

frient specifically states that the detector can provide a notification in addition to its audible alarm when integrated with a supported smart-home system.

Replaceable CR123A Battery

The detector uses one replaceable CR123A battery.

frient currently specifies an expected battery life of approximately 5 years when reporting every five minutes.

The detector can report:

• Battery level
• Low-battery warning

to compatible Zigbee systems.

Actual battery life may vary according to:

• Zigbee signal quality
• Reporting interval
• Alarm activity
• Operating temperature
• Battery quality

Minimum 100 m Open-Field Zigbee Range

frient specifies a wireless range of at least 100 meters in an open field.

Indoor performance will vary depending on:

• Walls
• Floors
• Metal structures
• Building materials
• 2.4 GHz interference
• Distance from the coordinator
• Placement of Zigbee router devices

The detector itself is battery powered and therefore does not extend the Zigbee mesh.

Compact Indoor Design

The HESZB-120 measures:

Ø65 × 40 mm

and weighs approximately 58.3 g, excluding retail packaging according to frient.

Reichelt lists the packaged product weight at approximately 0.121 kg.

The detector has an IP20 enclosure and is designed for dry indoor environments.

Certifications and Compliance

The frient Intelligent Heat Alarm is currently listed as:

• Zigbee 3.0 certified
• EN54-5 compliant
• DIN 14676 compliant
• CE conforming
• RoHS conforming
• REACH conforming

Reichelt additionally lists DIN EN 14604 and DIN 14676 for the HESZB-120 product sold through its store.

Always install heat and fire detection equipment according to the supplied documentation and applicable local building and fire-safety regulations.

Technical Specifications

Specification	Details
Product Name	frient Intelligent Heat Alarm
Model	HESZB-120
Product Type	Zigbee Heat / Fire Detector
Wireless Protocol	Zigbee 3.0
Zigbee Device Type	End Device
Fire Detection	Heat Based
Alarm Threshold	Above approximately 57°C
Siren Output	85 dB at 3 m
Temperature Sensor	Yes
Temperature Range	0°C to 50°C
Temperature Resolution	0.1°C
Typical Temperature Accuracy	±0.5°C
Maximum Temperature Accuracy Deviation	±2°C
Power Source	Battery
Battery	1 × CR123A
Battery Replaceable	Yes
Expected Battery Life	Approximately 5 years
Battery Reporting	Yes
Low-Battery Warning	Yes
Open-Field Zigbee Range	Minimum 100 m
Radio Sensitivity	-92 dBm
Typical Radio Output	+4 dBm
IP Rating	IP20
Operating Temperature	0°C to 50°C
Relative Humidity	Up to 95% RH, non-condensing
Dimensions	Ø65 × 40 mm
Product Weight	58.3 g
Color	White
Zigbee2MQTT	Supported
Zigbee Certification	Zigbee 3.0 Certified
Fire Standard	EN54-5
Additional Standard	DIN 14676
EAN / GTIN	5713594002446

The manufacturer currently lists -92 dBm radio sensitivity and typical +4 dBm output, while the supplied Reichelt page lists -98 dBm and +8 dBm. The table uses the current frient manufacturer specifications to avoid mixing conflicting retailer data.

Compatibility

Platform / Function	Compatibility
Zigbee 3.0 Gateway	Required for connected features
Zigbee2MQTT	Yes
Home Assistant via Zigbee2MQTT	Yes
SmartThings	Yes, with compatible Edge driver
Temperature Reporting	Yes on supported integrations
Battery Reporting	Yes on supported integrations
Low-Battery Warning	Yes on supported integrations
Fault Reporting	Yes through supported integrations
Siren Control	Yes through supported Zigbee2MQTT integration
Direct Wi-Fi	No
Direct Bluetooth	No
Zigbee Mesh Router	No, battery-powered end device
Outdoor Use	No

frient notes that not every feature is supported by every smart-home hub. SmartThings compatibility requires the appropriate Edge driver.

What’s Included?

• 1 × frient Intelligent Heat Alarm HESZB-120
• 1 × CR123A battery
• Mounting components
• Installation documentation

How to Set Up the frient HESZB-120

Step 1: Install the Detector

Insert the CR123A battery and mount the alarm according to the supplied installation instructions.

Step 2: Pair with Your Zigbee Gateway

Place your compatible Zigbee gateway or coordinator into pairing mode and add the HESZB-120.

Step 3: Test the Alarm

Use the detector's test procedure and confirm that the 85 dB local siren operates correctly before regular use.

Where Is a Heat Alarm Useful?

A heat detector can be a useful option in indoor areas where normal environmental conditions may trigger unwanted smoke alarms.

Typical examples include:

• Kitchens
• Rooms with fireplaces
• Dusty indoor storage areas
• Utility spaces
• Workshops within the approved environmental range

frient specifically highlights kitchens, fireplaces and dusty environments as locations where heat detection can help reduce false smoke alarms.

A heat detector should not automatically replace a smoke detector in locations where smoke detection is required. Follow your local fire-safety requirements to determine which alarm type and placement are appropriate.

Heat Alarm vs Smoke Alarm

The frient HESZB-120 does not detect smoke in the same way as an optical smoke alarm.

Instead:

Heat Alarm

• Responds to dangerous heat conditions
• Better suited to some smoky, steamy or dusty spaces
• Less likely to react to ordinary cooking smoke

Smoke Alarm

• Detects smoke particles
• Can provide earlier warning in many types of fire
• Usually required in key residential locations

Use the alarm type specified by local fire-safety regulations for each location.

Home Assistant Automation Ideas

Fire Alert Notification

Send a high-priority notification whenever the alarm reports a fire-related state.

Turn On Exit Lighting

Automatically turn on selected smart lights during an alarm to improve visibility.

Battery Warning

Send an alert when battery percentage becomes low or the low-battery state is reported.

Temperature Dashboard

Display the HESZB-120's current temperature reading in your Home Assistant room dashboard.

Device Fault Alert

Zigbee2MQTT exposes fault and reliability states, allowing you to create an alert if the detector reports a device problem.

Smart-home automations should supplement the detector's local fire warning and should never be treated as the sole life-safety mechanism.

Important Safety Notes

The frient HESZB-120 is fire-safety equipment first and a smart-home device second.

For safe use:

• Follow the manufacturer's installation instructions.
• Test the alarm regularly.
• Never depend solely on smartphone notifications.
• Replace the battery when a low-battery warning appears.
• Do not cover or obstruct the detector.
• Keep the device within its specified temperature and humidity range.
• Do not install the IP20 detector outdoors or in wet environments.
• Do not replace required smoke alarms with a heat detector unless permitted by applicable regulations.
• Follow local fire-safety requirements for alarm placement and quantity.

Pros

• Heat-based fire detection
• Helps reduce nuisance alarms caused by smoke or dust
• 85 dB local siren
• Zigbee 3.0 connectivity
• Built-in temperature monitoring
• Zigbee2MQTT support
• Home Assistant integration through Zigbee2MQTT
• SmartThings compatibility with appropriate driver
• Battery percentage reporting
• Low-battery reporting
• Fault and reliability reporting
• Remote siren control supported by Zigbee2MQTT
• Replaceable CR123A battery
• Approximately 5-year battery life
• Minimum 100 m advertised open-field range
• Compact 65 mm design
• EN54-5 and DIN 14676 compliant
• Zigbee 3.0 certified

Cons

• Compatible Zigbee gateway required for smart notifications
• Heat detector does not replace required smoke alarms in every location
• IP20 rating limits use to suitable indoor areas
• Battery-powered device does not extend the Zigbee mesh
• Available smart features depend on the connected hub or integration

Who Should Buy the frient HESZB-120?

The frient Zigbee Heat Alarm is particularly suitable for people who:

• Need a heat alarm for a kitchen or similar indoor area
• Use Home Assistant
• Use Zigbee2MQTT
• Want remote fire notifications
• Want temperature monitoring from the same device
• Already operate a Zigbee smart home
• Want battery and fault status in a smart-home dashboard
• Need an alarm for areas where dust or normal cooking smoke can cause nuisance smoke alarms

The HESZB-120 should be selected as part of a properly planned fire-alarm system rather than used as a universal substitute for smoke detectors.

Frequently Asked Questions

What is the frient HESZB-120 Zigbee Heat Alarm?

The frient HESZB-120 is a Zigbee 3.0 heat-based fire detector with an 85 dB local siren, built-in temperature sensor and replaceable CR123A battery. It is designed to detect dangerous heat rather than ordinary smoke.

Who should buy the frient Zigbee Heat Alarm?

The frient Zigbee Heat Alarm is suitable for Zigbee smart-home users who need heat-based fire detection in locations such as kitchens, fireplace rooms or dusty indoor areas where smoke detection may produce unwanted alarms.

How does the frient HESZB-120 work?

The HESZB-120 monitors heat conditions and activates its local siren when a fire-related heat threshold is reached. It can also transmit alarm, temperature, battery and device-status information through Zigbee to a compatible smart-home system.

What is included with the frient HESZB-120?

The package includes the frient Intelligent Heat Alarm HESZB-120, a CR123A battery, mounting components and installation documentation.

Does the frient HESZB-120 work with Zigbee2MQTT?

Yes. Zigbee2MQTT supports the HESZB-120 hardware family and exposes alarm, temperature, battery, fault, reliability and siren-control functions.

Does the frient Heat Alarm work with Home Assistant?

Yes. The frient HESZB-120 can be integrated with Home Assistant through Zigbee2MQTT using a compatible Zigbee coordinator.

How loud is the frient HESZB-120?

The integrated siren is rated at 85 dB measured at 3 meters.

How long does the frient HESZB-120 battery last?

frient specifies an expected battery life of approximately 5 years using one replaceable CR123A battery when reporting every five minutes. Actual battery life can vary according to network conditions, reporting frequency, alarm activity and battery quality.

Why Buy the frient HESZB-120 Zigbee Heat Alarm?

The frient Intelligent Heat Alarm HESZB-120 combines heat-based fire detection with Zigbee 3.0 connectivity, temperature monitoring and a strong local audible alarm.

Its biggest advantage is its ability to provide fire detection in indoor areas where smoke, steam or dust may cause unwanted smoke-detector activations. The built-in 85 dB siren provides immediate local warning, while compatible Zigbee systems can add remote notifications, battery monitoring and device-status reporting.

For Home Assistant and Zigbee2MQTT users, the HESZB-120 is especially capable because Zigbee2MQTT exposes temperature, battery, fault, reliability and siren-control functions in addition to the alarm state.