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
The Shelly H&T Gen3 is a Wi-Fi smart humidity and temperature sensor featuring a large e-paper graphic display for clear, easy-to-read environmental data.
Main Features
- Wi-Fi Connectivity: Connects to your home Wi-Fi network for remote monitoring via smartphone apps or compatible devices.
- Large E-Paper Graphic Display: Provides high-contrast, glare-free visualization of temperature and humidity readings.
- Digital Clock: NTP-synchronized real-time clock with automatic time updates.
- Smart Home Integration: Compatible with Google Assistant, Amazon Alexa, and Samsung SmartThings for voice control and automation.
- USB Type-C Port: Used for continuous power supply. Not suitable for charging internal batteries.
- Bluetooth Connectivity: Supports Bluetooth 4.2 for setup assistance and local configuration.
- User-Friendly Interface: Includes a reset button (behind the back cover) for manual interaction and device management.
- Battery Operation: In battery mode, the device wakes every minute to measure conditions. It reports changes only if thresholds are exceeded (0.5 °C or 5% RH), but unconditionally reports after two hours without update. A 5-minute cooldown period prevents self-heating.
- USB-Powered Operation: When powered via USB, the device wakes every 5 minutes, measures, updates the display, and sends data unconditionally to connected channels.
- Environmental Specifications: Operates in temperatures from 0 °C to 40 °C (32 °F to 105 °F) and relative humidity of 30% to 70% RH.
- Power Supply Options: Powered by 4 × AA batteries (LR6, 1.5 V, not included) or via USB Type-C.
- Wireless Connectivity: Supports Wi-Fi (802.11 b/g/n) and Bluetooth 4.2 with indoor range up to 30 m (100 ft) and outdoor up to 50 m (160 ft).
- Microcontroller Unit (MCU): ESP-Shelly-C38F with 8 MB flash memory.
These features make the Shelly H&T Gen3 ideal for residential, multi-dwelling units (MDUs), light commercial, university/college, and other environments requiring reliable, low-maintenance environmental monitoring with smart home integration.
Main Applications
- Residential
- Multi-Dwelling Units (MDUs): apartments, condominiums, hotels
- Light Commercial: small offices, retail stores, restaurants, gas stations
- University/College
Integrations
Amazon Alexa Supported Capabilities
Yes
Google Smart Home Supported Traits
Yes
Samsung SmartThings Supported Capabilities
Yes
Device Electrical Interfaces
USB Type-C Port
- Supplies power to the device
- Cannot be used to charge internal batteries
Connectivity
- Wi-Fi
- Bluetooth
User Interface
Inputs
- Reset Button: Located behind the back cover
Reset Button Actions
Brief press:
- If in Sleep mode → enters Setup mode
- If in Setup mode → returns to Sleep mode
Hold for 5 seconds:
- If in Setup mode → enables the device’s access point
Hold for 10 seconds:
- If in Setup mode → performs factory reset
Outputs
- E-Paper Graphic Display
Current time
Device is in Setup mode
Device access point is enabled
Humidity readings
Receiving over-the-air firmware update – progress shown as percentage
Device has reported current readings to the Cloud. If missing, displayed values may differ from Cloud data.
Wi-Fi signal strength indicator
Battery level indicator. Shows empty when USB-powered.
Bluetooth connectivity is enabled
Error during firmware update
Measuring and Reporting
On Batteries
When operating on battery power:
- Wakes every minute to take measurements. Updates the screen if there's a change of ≥0.2 °C or ≥3% RH. The default reporting threshold is ≥0.5 °C or ≥5% RH — smaller changes do not trigger a report.
- If no threshold-based report is sent within two hours, the device unconditionally reports its status to Shelly Cloud and all connected channels.
- A 5-minute cooldown period is enforced after each measurement to prevent self-heating; during this time, the device remains inactive.
On USB Power Supply
When powered via USB:
- Wakes every 5 minutes
- Performs measurement
- Updates the display
- Unconditionally reports data to all connected channels
- Sleeps for 5 minutes
User-Initiated Report
Pressing the reset button (behind the cover) triggers:
- Wake-up
- Measurement
- Display update
- Unconditional report to all channels
- 5-minute sleep cycle
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 flat surface) Wall mounting using screws (head diameter: 5–7 mm / 0.20–0.28 in, max thread diameter: 3 mm / 0.12 in) 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 (4 × AA LR6, 1.5 V, not included) USB Type-C (power adapter and cable not included) |
| Estimated Battery Life | Approx. 1 year (varies based on battery type, environmental conditions, and network strength) |
| 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 (indoor) Up to 50 m / 160 ft (outdoor) (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 (indoor) Up to 30 m / 100 ft (outdoor) (Depends on local conditions) |
| Microcontroller Unit (MCU) | |
| CPU | ESP-Shelly-C38F |
| Flash Memory | 8 MB |
| Firmware Capabilities | |
| Schedules | No |
| Webhooks (URL actions) | 10 hooks, up to 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 (2025-07-22)
- 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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