GEM208 split-type smart thermostatic radiator valve for residential home heating applications

GEM208 Wireless Smart Thermostatic Radiator Valve

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Key Functions

Sensor‑Separable Design – Place the Sensor Where People Actually Live (Optional GEM208S)

True Spatial Comfort – ±1℃ Target‑Area Temperature Accuracy

Significant Energy Savings – Up to 30% Heating Cost Reduction

Flexible 2‑in‑1 Installation – One‑Piece Mode or Split‑Mode with External Sensor

Universal Retrofit Fit – 99% Valve Compatibility with Rich Adapters

Simple Operation – One‑Button Temperature Select & APP Control

Front view of GEM208 split-type smart thermostatic radiator valve kit

Front view of GEM208S external sensor for split-type TRV

Right side view of GEM208 split-type smart thermostatic radiator valve

Home Smart Thermostatic Radiator Valves GEM208 Wireless Smart Thermostatic Radiator Valve

Product Overview

The GEM208 wireless Smart Thermostatic Radiator Valve is a split-type solution that separates the sensor from the actuator, solving the problem of one-piece TRVs that measure heat trapped around the radiator body instead of actual room temperature. As a split-type model in our product portfolio, the GEM208V actuator mounts on the valve, while the optional GEM208S external sensor (sold separately) can be placed on a wall or desktop, away from radiator heat, sensing the temperature where people actually live. Use it as a standard one-piece TRV with built-in sensor, or add the external sensor for split-mode operation. Powered by 2×AA batteries (V) and 2×AAA (S), both deliver 15-month battery life with 3-second quick pairing. Core features include ±1℃ target-area accuracy, 30% energy savings, and 99% valve compatibility. Ideal for retrofit projects where radiators sit under windows, behind curtains, or in corners.

Recommended reading: Smart Thermostatic Radiator Valve

GEM208 split-type smart thermostatic radiator valve installed on living room radiator

Product Features

Sensor‑Separable Design – True Spatial Comfort

Use built‑in sensor for one‑piece mode, or pair with optional GEM208S for split‑mode. Place the sensor on wall or desktop, away from radiator heat – sensing actual room temperature where people live, not trapped heat around the valve.
±1℃ Target‑Area Accuracy

Delivers ±1℃ accuracy for the occupied area – not just the valve body. Because the sensor is placed where people actually are, the system controls to the comfort zone that matters.
30% Energy Savings

Precision spatial sensing eliminates overheating and short‑cycling. Heating to actual room temperature, not radiator‑adjacent readings, cuts boiler runtime by up to 30%.

Flexible 2‑in‑1 Installation

One device, two ways to use – one‑piece with built‑in sensor, or split‑system with external GEM208S. Adapts to any environment: windows, curtains, corners.
99% Valve Compatibility

Standard M30×1.5mm with comprehensive adapters covers Danfoss RA/RAV/RAVL, Caleffi, Giacomin, Comap, Herz, TA, and more – 99% of common radiator valves.
15‑Month Battery Life & 3‑Second Pairing

GEM208V (2×AA) and GEM208S (2×AAA) both deliver 15 months on standard alkaline batteries. Pair V and S in just 3 seconds. Local grouping supports multiple units without cloud dependency.

Product Selector

Model No.	Programmable	RF	ZIGBEE 2.0	WIFI	Power	Manual
GEM208S-TF+GEM208V-TFZ	√	√	√		Battery	download

Product Parameters

GEM208 split-type smart thermostatic radiator valve kit product front view

GEM208 wireless Smart Thermostatic Radiator Valve

GEM208V-TFZ

Power source: 2*AA 1.5V battery (LR6) (Don’t use the rechargeable battery)

Temperature setting accuracy: 0.5°C(app)

Room temperature display range: 0°C~50°C(app)

Operation temperature range: 5°C~30°C(app)

Shipping & storage temperature: -10°C~60°C

Frequency: Zigbee 2.4GHz or RF 868MHz

Zigbee wireless transmit range: 30m in open air

RF wireless transmit range: 60m in open air

IP class: IP21

Connection: M30x1.5mm

GEM208S-TF

Power source: 2*AAA 1.5V batteries (LR03) (Don’t use the rechargeable battery)

Temperature setting accuracy: 0.5°C

Temperature display range: 0-50°C

Operation temperature range: 5-30°C

RF frequency: 868MHz

Sensor dimensions: φ53.6mm*12.7mm

Sensor base dimensions: 72mm*72mm*17.5mm

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A limited number of sample opportunities may be available each month, subject to availability.

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Product Dimensions

Product dimension drawing for GEM208 split-type smart thermostatic radiator valve

Product Installation

Installation guide for GEM208 split-type smart thermostatic radiator valve

Product Application Scenarios

The GEM208 excels in retrofit projects where radiators are poorly positioned – under windows, behind curtains, or in corners – and one‑piece TRVs can't deliver accurate room temperature. Perfect for bedrooms, living rooms, senior homes, rental apartments, and hotels. Optional external sensor provides true spatial comfort with 30% energy savings.