Temperature and humidity Wi‑Fi controller Sonoff THR320D 20A LDC for remote monitoring and automatic control

Smart Wi‑Fi temperature and humidity controller SONOFF THR320D converts a conventional thermostat into a smart controller, enabling automated environmental control and remote monitoring of temperature and humidity. It supports multiple sensor types for different applications, offers dry contact output for integration with existing systems, and can handle high-load devices up to 20 A. The unit stores up to six months of temperature and humidity history and supports LAN control so basic operation continues when Wi‑Fi is unavailable.

Advantages

The controller uses a V0 class flame-retardant polycarbonate casing and includes a varistor to absorb peak voltages from lightning strikes or unstable power supply. An upgraded RJ9 4P4C sensor connector supports hot-plugging for a stable and reliable connection. The device provides timely push notifications when measured values or output states change and can export six months of hourly temperature and humidity history in .xlsx format. It integrates with eWeLink, can be added to Home Assistant via an add-on, supports IFTTT for cross-brand automation and offers voice control and web-based management.

Suitable for

• Automating and remotely monitoring home heating systems and electric floor heating
• Environmental monitoring for baby rooms or nurseries
• Monitoring water temperature for aquariums
• Controlling irrigation and soil moisture for plants and greenhouses
• Integrating with boilers or systems that use dry (volt-free) contacts

Key specifications

• Power input/output: 100–240 V AC, 50/60 Hz
• Maximum load current: 20 A
• Dry contact output rating: 5–30 V DC, 1 A max
• Wireless: Wi‑Fi IEEE 802.11 b/g/n, 2.4 GHz
• Casing material: V0 class flame‑retardant polycarbonate (PC)
• Sensor connector: RJ9 4P4C, hot-plug supported
• Mounting options: DIN rail or panel
• Measurement footprint: approx. 98 mm × 54 mm (depth not specified)

How to use

Install the controller on a DIN rail or panel and connect power (100–240 V AC). Attach the appropriate sensor (temperature & humidity, waterproof temperature, or soil moisture) using the RJ9 4P4C connector. Configure the device using the eWeLink app or web control, set temperature and humidity thresholds, and create automations or scenes as needed. For integration with existing systems, connect the device’s dry contact output to the external controller or boiler input; note the dry contact only switches the circuit and does not supply power. LAN control ensures local operation continues if Wi‑Fi is lost.

Usage recommendations

Place sensors in representative locations for accurate readings (avoid direct sunlight, heating vents or splashing water unless using the waterproof sensor). Use the appropriate sensor type for the application (waterproof sensor for aquariums, soil moisture sensor for plants). Export historical data periodically if long-term records are needed and ensure any high-load equipment connected does not exceed the 20 A rating.