Smart thermostatic valves: useful for saving energy?
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Stefano Fonseca ist Ingenieur für Energie und Umwelt mit über sechs Jahren Erfahrung in der technischen Gebäudeausrüstung (TGA). Er kombiniert technisches Fachwissen mit einer Leidenschaft für verständliche Kommunikation. Seit mehr als fünf Jahren schreibt er als freiberuflicher Redakteur über erneuerbare Energien und nachhaltiges Wohnen, insbesondere über Photovoltaik und Wärmepumpen.
When the heating system thinks before it heats: Smart thermostatic valves promise greater comfort and savings in heating costs at the same time. But what is behind the technology and is it really worth making the switch? Here you can find out everything you need to know about smart radiator thermostats.
What are smart thermostatic valves?
Smart thermostatic valves are one type of thermostatic valves and serve as digital radiator controllers that automatically and efficiently control the room temperature. They can be controlled via app, schedule or sensors and adjust the heating output to actual requirements — for example through geofencing, weather data or learning algorithms.
How do smart thermostatic valves work?
Smart thermostatic valves automatically adjust the radiator temperature to actual requirements. To do this, they use sensors, schedules and digital control via app. Some models integrate geofencing, which recognizes whether residents are at home, or include weather data. This means that heating is only carried out when it is really necessary. The valves open and close the heating flow electronically and can react individually to room and user behavior.
Who are smart thermostats worthwhile for?
Smart thermostats are worthwhile for households with changing daily routines, unrenovated buildings or high energy consumption. You save on heating costs by only heating when it is really necessary. They are particularly useful for people who are often away from home, live in rented apartments without central control or want to actively optimize their energy consumption.
They are less profitable in well-insulated buildings with constant living patterns or centrally controlled heating, where the influence on temperature is limited.
What savings are possible?
Compared to conventional thermostats upto 10% heating costs save. This is confirmed by the Oeko-Institut and consumer associations, among others.
Example calculation for an 80 m² apartment with gas heating:
- Annual energy consumption: approx. 12,000 kWh
- gas price (April 2025): approx. 10 cent/kWh
- Annual heating costs: 12,000 kWh × 0.10 €/kWh = 1.200€
- Savings with smart thermostats: €1,200 × 10% = 120€ savings per year
Depending on the model, the purchase costs for smart thermostatic valves are around 40 to 80€ per piece. With five radiators, that would be between 250 and 400€ once. The investment often pays off after 2 to 4 years, depending on heating patterns and living conditions.
What is the experience with smart radiator thermostats?
Experience reports from various forums show a differentiated picture of smart radiator thermostats. Many users report positive experiences in terms of comfort and energy savings, while others point out challenges when setting up and using them.
A user has installed smart thermostats from EVE in his single-family home and combined them with window contacts and geofencing. He reports efficient heating control, particularly as he and his wife do not have fixed working hours.
Another user reports in ThinkPad-forumthat he was able to reduce his gas consumption by around 30% by using smart thermostats with schedules and window contacts in an old building. However, he underlines that such savings depend heavily on individual heating behavior.
Some users criticize the fact that certain functions of smart radiator thermostats are only available via paid subscriptions and that the devices depend heavily on cloud services. This may result in restrictions, particularly if the manufacturer makes changes to the services.
One example of this is the Tado radiator thermostat V3+, which features such as geofencing and window open detection are only available with a paid subscription. Without an Internet connection, schedules or app control also work, which increases dependency on the cloud.
Are there tests with smart radiator thermostats?
There are comprehensive tests on smart radiator thermostats. For example, he has SPIEGEL has published a comprehensive test report on smart radiator thermostats. In this study, eleven models were assessed in terms of their energy saving potential, user-friendliness and additional functions. The article highlights that smart thermostats can be particularly useful for users with irregular daily routines and in households without central heating control. However, potential disadvantages such as cloud dependency and additional costs are also pointed out.
The following is an overview of the tested models, including price, advantages and disadvantages:
How do I install smart thermostatic valves?
Smart thermostatic valves can usually be installed without specialist personnel — the radiator can be digitally controlled in just a few simple steps. Here is a simple step-by-step guide:
- Remove the old thermostat valve: Turn off the thermostat head counterclockwise. For fixed models, loosen the mounting screw or union nut beforehand.
- Install adapter (if necessary): Check whether the new smart thermostat requires an adapter. Most devices include suitable adapters for Danfoss, Heimeier & Co.
- Screw on a new thermostat: Place the smart thermostat on the valve and carefully screw it in place. Make sure the fit is tight, but avoid overturning.
- Insert batteries: Open the battery compartment (usually on the side or back) and insert the included batteries.
- Start initialization: Once switched on, the thermostat calibrates automatically. Wait for the process and follow the instructions on the display or in the app.
- Install and pair the app: Download the appropriate app, create an account and connect the thermostat via Bluetooth, WLAN or Zigbee.
- Set up the heating profile: Set temperature schedules, enable geofencing or window-open detection, and test control.
Tips for optimal use and adjustment
- Create schedules: Set individual heating times for each room — e.g. in the bathroom in the morning, in the living room in the evening.
- Enable geofencing: Let the heating automatically turn down when no one is home.
- Set room temperatures realistically: 20-21 °C in the living room, 17-18 °C in the bedroom are usually completely sufficient.
- Use window open detection: Thermostat detects open windows and automatically lowers the heating.
- Check app settings regularly: Optimize plans as daily routines change.
- Keep an eye on battery level: Change batteries in good time to avoid heating interruptions.
- Activate learning function (if available): Some models adjust themselves to the heating behavior.
- Activate parental controls: Prevents accidental adjustment of the device.
- Integrate weather data: Some thermostats take outside temperatures into account for more efficient control.
- Ventilate radiators regularly: Air in the system may interfere with temperature control.
Is it worth the investment?
Investing in smart thermostatic valves is particularly worthwhile for households with changing attendance times, high heating requirements or the desire for more comfort and control. After just a few heating seasons, the purchase costs can be amortized by saving energy. There are also benefits such as automated schedules, remote control via app and integration into existing smart home systems. However, the right setup and regular adjustment to your own lifestyle are a prerequisite for full use.
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