Shelly H&T Gen3

Device Identification
- Device name: Shelly H&T Gen3
- Device model: S3SN-0U12A
- Device SSID: ShellyHTG3-XXXXXXXXXXXX
- Device Bluetooth ID: 0x1809
Short Description
Shelly H&T Gen3 (the Device) is a Wi-Fi smart humidity and temperature sensor, featuring a large e-paper graphic display.
Main Features
- Wi-Fi Connectivity: The device can connect to your home Wi-Fi network, allowing you to remotely monitor humidity and temperature data through a smartphone app or other compatible devices.
- Large E-Paper Graphic Display: It features a large e-paper graphic display that provides clear and easy-to-read humidity and temperature information.
- Digital Clock: NTP-synchronized real-time clock.
- Integration with Smart Home Platforms: You can integrate the Shelly H&T Gen3 with popular smart home platforms, including Google, Alexa, and Samsung SmartThings. This enables voice control and automation capabilities through these platforms.
- USB Type-C Port: It includes a USB Type-C port for powering the device. While it cannot be used to charge the device's batteries, it allows for continuous power through a USB connection.
- Bluetooth Connectivity: Bluetooth is available for inclusion purposes, which may be useful during the setup process.
- User-Friendly Interface: The device provides a user-friendly interface with a reset button for manual interactions.
- Battery Operation: When running on batteries, the device wakes up at set intervals to take measurements of humidity and temperature. It reports changes in data based on predefined thresholds and unconditionally reports its status to the cloud if no reports are made within a specified time.
- USB-Powered Operation: When powered via its USB port, the device wakes up more frequently, performs measurements, updates its display, and unconditionally reports data to connected channels.
- Environmental Specifications: The device is designed for use in various environments, with an operational temperature range of 0°C to 40°C (32°F to 105°F) and a recommended humidity range of 30% to 70% RH.
- Power Supply Options: It can be powered by 4 AA batteries (not included) or a USB Type-C connection.
- Wireless Connectivity: The device supports Wi-Fi (802.11 b/g/n) and Bluetooth 4.2 protocols with specified indoor and outdoor range capabilities.
- MCU (Microcontroller Unit): The device is equipped with an ESP-Shelly-C38F with 8 MB of flash memory.
These features make the Shelly H&T Gen3 a versatile and convenient device for monitoring humidity and temperature in residential, multi-dwelling units, light commercial, university/college, and other settings, with the added benefits of smart home integration and ease of use.
Main Applications
- Residential
- MDU (Multi Dwelling Units – apartments, condominiums, hotels, etc.)
- Light commercial (small office buildings, small retail/restaurant/gas station, etc.)
- University/college
Integrations
- Amazon Alexa: Yes
- Google Smart Home: Yes
- Samsung SmartThings: Yes
Device Electrical Interfaces
USB Type-C Port

- To supply power to the device
- Cannot be used to charge batteries inside the device
Connectivity
- Wi-Fi
- Bluetooth
User Interface
Inputs
- Reset button (behind the back cover)

Reset Button Actions
Press briefly:
- If the device is in Sleep mode, puts it in Setup mode.
- If the device is in Setup mode, puts it in Sleep mode.
Press and hold for 5 seconds:
- If the device is in Setup mode, enables its access point.
Press and hold for 10 seconds:
- If the device is in Setup mode, factory resets the device.
Outputs
- E-paper graphic display

| Icon | Meaning |
|---|---|
![]() | Current time |
![]() | The device is in Setup mode |
![]() | The device access point is enabled |
![]() | Humidity readings |
![]() | The device is receiving over-the-air update (shows progress as percentage) |
![]() | The device has reported current readings to the Cloud. If missing, the display may differ from cloud data |
![]() | Wi-Fi signal strength indicator |
![]() | Indicates battery level. Shows empty battery when only USB-powered |
![]() | Bluetooth connectivity is enabled |
![]() | Error while updating firmware |
Measuring and Reporting
On Batteries
- Wakes up every minute to perform a measurement. If there is a 0.2 °C temperature or 3% humidity difference, the screen updates.
Default threshold for reporting: 0.5 °C or 5%. Smaller changes result in no report.
- If no report is sent based on threshold values for two hours, the device unconditionally reports its status to Shelly Cloud and other connected channels.
- Due to self-heating, a 5-minute cool-down period is imposed during which the device does not wake up.
On USB Power Supply
If powered via USB:
- Wakes up every 5 minutes
- Performs measurement
- Updates screen
- Unconditionally reports to all connected channels
- Sleeps for 5 minutes
User-Initiated Report
Pressing the reset button (behind the cover):
- Device wakes up
- Performs measurement
- Updates screen
- Unconditionally reports to all connected channels
- Sleeps for 5 minutes
Specifications
| Category | Value |
|---|---|
| Physical | |
| Size (H×W×D): | 70×70×26 mm / 2.76×2.76×1.02 in (without stand) 70×70×45 mm / 2.76×2.76×1.77 in (with stand) |
| Weight | 47 g / 1.66 oz |
| Mounting | With stand (on horizontal surface) Wall mounting (using screws with head diameter 5–7 mm / 0.20–0.28 in and max 3 mm / 0.12 in thread diameter, or double-sided foam sticker) |
| Shell material | Plastic |
| Shell color | White Mocha: C:0 M:12 Y:28 K:12 Ivory: C:3 M:4 Y:14 K:8 Black: C:0 M:0 Y:0 K:100 |
| Environmental | |
| Ambient working temperature | 0 °C to 40 °C / 32 °F to 105 °F |
| Humidity | 30% to 70% RH |
| Max. altitude | 2000 m / 6562 ft |
| Electrical | |
| Power supply | Batteries |
| Battery type | 4 AA (LR6) 1.5 V (not included) |
| Estimated battery life | Approx. 1 year (varies by battery quality, temperature, humidity changes, and network strength) |
| Power supply (USB) | Type-C (power adapter and cable not included) |
| Sensors, meters | |
| Internal temperature sensor | No |
| Temperature sensor | Yes |
| Humidity sensor | Yes |
| Radio | |
| Wi-Fi | |
| Protocol | 802.11 b/g/n |
| RF band | 2401 – 2495 MHz |
| Max. RF power | < 20 dBm |
| Range | Up to 30 m / 100 ft indoors and 50 m / 160 ft outdoors (Depends on local conditions) |
| Bluetooth | |
| Protocol | 4.2 |
| RF band | 2400 – 2483.5 MHz |
| Max. RF power | < 4 dBm |
| Range | Up to 10 m / 33 ft indoors and 30 m / 100 ft outdoors (Depends on local conditions) |
| Microcontroller Unit | |
| CPU | ESP-Shelly-C38F |
| Flash | 8 MB |
| Firmware Capabilities | |
| Schedules | No |
| Webhooks (URL actions) | 10 with 2 URLs per hook |
| Scripting | No |
| MQTT | Yes |
Shelly Smart Control
Shelly Web User Interface
Troubleshooting
...
Components and APIs
Compliance
- Shelly H&T Gen3 multilingual EU declaration of conformity 226 2025-12-05
- Shelly H&T Gen 3 Matte Black UK PSTI ACT Statement of compliance
- Shelly H&T Gen 3 Matte White UK PSTI ACT Statement of compliance
- Shelly H&T Gen 3 Mocha UK PSTI ACT Statement of compliance
- Shelly H&T Gen 3 Ivory UK PSTI ACT Statement of compliance
Compliance archive
Printed User Guide
Installation Guides
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