Thermostatic Radiator Valves
This text is machine translated.
Useful information about radiator thermostats - room-specific temperature control for a feeling of well-being
The radiator thermostats are responsible for regulating the heat output in the heating system. Modern thermostats ensure a comfortable climate in your rooms at all times and help to save heating costs in apartments, offices and houses. To wake up in the morning, the bathroom receives you with warm warmth, after the refreshing shower, the heating is automatically turned down as soon as you open the window to ventilate. If the last member of the family leaves the apartment, the heating goes on its own into the savings mode with frost protection.
In the office, the meeting room for the meeting marathon starts at 11 am and is already pleasantly tempered. After the meetings at 4 p.m., the presence detection, time-controlled temperature programs or a simple push of a button until the next working day provide for economical maintenance heat. Until you come home after work, the living rooms are already heated to the desired temperature.
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Why it is worthwhile to change the radiator thermostats
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How does a radiator thermostat work?
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What types of radiator thermostats are there?
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This saves you money by automatically lowering the heating
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Pay attention to these points when buying heating thermostats
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Valve diameter and valve adapter for heating thermostats
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Changing the radiator thermostats is as easy as that
Why it is worthwhile to change the radiator thermostats
The current generation of heat-sink thermostats offers you many possibilities to control the heat output of the heating system individually and according to your requirements and at the same time to protect the environment. As soon as the preset temperature or heat level is reached, the thermostat reduces the heat supply and thus the heat output into the rooms. If the temperature falls below your set point, the heating will warm again.
This simple and energy-efficient principle enables you to heat apartments, houses, work rooms and rental properties in a way that is tailored to the needs of users. With the right radiator thermostats, you, your family, employees or tenants no longer need to compromise on comfort for optimized energy consumption. Ideally, you save up to 25 percent of the usual heating costs. And even under less optimal conditions, new radiator thermostats have a noticeable positive effect on your wallet. The purchase of energy-saving radiator thermostats often pays off for owners and tenants after the first heating period. By the way, you actively contribute to climate protection by replacing defective or outdated thermostats and improve your personal ecological balance or that of your company.
How does a radiator thermostat work?
Radiator thermostats, also known as thermostatic valves, are mechanical or electronic temperature controllers. The thermostats control the flow of liquid through the radiators and control the heat that is released into the room, depending on the ambient temperature.
For this purpose, the controllers in their interior have a temperature sensor, which is filled with liquid, wax or gas depending on the version. Depending on the outside temperature, these elements will be combined or expanded. This moves a metal pin on the valve that opens the valve more or less to control the flow of hot water.
Each thermostat has a thermostat head for temperature control. It is either labeled with symbols or has a display and pressure switch for exact setting of the temperature in case of electronic heat-sink thermostats.
In addition to integrated temperature sensors, it is also possible to mount them as a thermostat unit independant of the radiator in the room. Room temperature sensors are remote sensors and connected to the radiator valve or the underfloor heating via cable or radio.
What types of radiator thermostats are there?
Thermostatic radiator valves differ in their design, functions and operation.
Mechanical thermostatic radiator valves
Mechanical thermostatic valves operate with the help of a built-in temperature sensor and are still in operation in many houses today. They are the successor to the heavy-duty manual valves without temperature sensors, which only allow the valve to be opened and closed. You can set mechanical radiator thermostats manually by turning the control. They are cheap to buy, but they are limited to the basic function of heat regulation, do not offer comfort equipment or energy efficiency functions.
Electronic thermostatic radiator valves
Electronic thermostats and radio radiator thermostats are a little more expensive than mechanical controllers, but they usually measure the ambient temperature more accurately and can be controlled more comfortably.
Electronic thermostats have a decisive advantage over mechanical thermostats: They can be programd in advance. This means that you can set and control the temperatures in individual rooms according to the user's need for heat.
The thermostat then regulates the room temperature itself The automatic mechanism is not only very comfortable, but also saves a lot of energy. In addition, many models have useful additional functions, such as the detection of open windows, a child lock or a limescale protection function.
Wireless radiator thermostats
Wireless thermostats are the optimized version of the electronic radiator thermostats for greater heat comfort. The convenience is that you can set and program wireless thermostats not only directly on the thermostat head, but also wirelessly. In some devices, the temperature sensors can be freely positioned in the rooms. This allows a more accurate measurement of the ambient temperature. The radio connection allows you to control multiple thermostats via a single control unit was beneficial in apartments and houses with many rooms.
Smart radiator thermostats
Smart thermostats are networked via the home network and the Internet and offer the greatest comfort gain. You can control them via app on your smartphone from all over her. In addition, smart controls are often compatible with Amazon echo, Google Assistant and Apple Siri. Then you can control the heating simply by calling with your voice.
In the app, you group the controls into heating zones for common control, set up day programs, week programs or month programs and activate holiday mode in case of longer absence. You can switch between different heating programs and create individual profiles. By communicating with your smartphone, smart thermostats know when you are on the way home and are already heating up. Local weather data can also be included in the automatic temperature control.
Thermostatic radiator valves that can be operated via an app can often be integrated into existing smart home systems such as HomeMatic IP, Bosch Smart Home, Magenta SmartHome, Apple HomeKit or the AVM Fritz!Box series. The integration into scenes results in extensive interaction possibilities with the sensors and actuators in the building. The Conrad Connect IoT platform enables building automation across systems.
This saves you money by automatically lowering the heating
With the intelligent heating control, you heat the individual rooms according to your needs and not by fixed radiator thermostats with constant room temperature. The question is, when and for whom temporary lowering of the room temperature is worthwhile? After all, the subsequent heating process consumes energy again.
How much you can save with the automatic heating system and how much the ecological profit is depends above all on the nature of the building. Temporary throttling of the thermostats in the absence and the associated reduction of the heat output by the radiators is most worthwhile in older, poorly insulated houses. This is where the savings effect is greatest, because the walls, windows and doors lose a lot of valuable heat around the clock. If the rooms are less heated during absence, less heat escapes accordingly. The longer the rooms are unused, the greater the savings effect.
Even many insulated buildings emit heat from inside to outside, albeit to a lesser extent. This is why you benefit from the savings effect and climate protection even in insulated houses and apartments with intelligent radiator thermostats.

Pay attention to these points when buying heating thermostats
Thermostats are available individually or as starter sets. When you choose new radiator thermostats, the following features are relevant:
Easy operation
In comfort mode or automatic mode, the radiator thermostats automatically provide for a healthy room heat for maximum heat comfort to feel comfortable. The thermostats know when it gets too cold or too warm. The heat output is automatically adjusted room by room according to the respective usage habits. The thermostat automatically controls the desired comfort temperature targets. If required, the predefined temperature can be individually increased or lowered on each thermostat.
Detects open windows
When the room is aired, the window-on detection of the intelligent heating control automatically reduces the temperature to save heating costs. The room temperature is lowered for a certain time and just so far to prevent the room air from cooling. Networked smart home thermostats can also be linked to window contacts. When you open the window, the control is automatically turned down and upshifted when you close the window. The detection of open windows can significantly reduce the additional costs in offices, meeting rooms, house entrances and families with children.
Display
A large, easy-to-read and illuminated display makes it easy to set the target heat, read the currently measured temperature and program the thermostat directly on the device. For visually impaired users, noticeable markings on the thermostat head are helpful.
Eco mode and holiday mode
The room temperature in temporarily unused rooms is lowered after leaving via Eco mode to save energy. However, the room does not cool completely. Holiday mode reduces the temperature reduction over a longer period of time.
Battery warning
The energy supply of electronic radiator thermostats is done via a battery, which you rarely need to change. Models with battery warning inform the user when the battery charge level reaches a low level. After the battery warning, the device continues to function for a few weeks or days and you have sufficient time to prepare replacement batteries.
Valve protection / limescale protection
To protect the radiator valve, the radiator thermostat travels through an automatic valve protection run at regular intervals. The valve is completely turned up and closed once or twice in a row. The routine valve run prevents limescale deposits and prevents them from getting stuck.
Frost protection
In frost protection mode, the radiator thermostat opens the heater valve to prevent damage to the building as soon as the room temperature falls below a critical level.
Childproof
The child lock prevents unintentional adjustment of the temperature controller.
Valve diameter and valve adapter for heating thermostats
When selecting new thermostats, pay attention to the appropriate valve diameter. Many models come with adapters that simplify installation. With the accompanying adapters, it is not a problem to install on common radiator valves such as the Danfoss RA, Danfoss RAV and Danfoss RAVL. Please refer to the product description to find out which valve adapters are included or available as accessories.
Changing the radiator thermostats is as easy as that

Heating thermostats replace the previous thermostats on the radiators. The assembly requires almost no technical skill. The thermostat is changed without any intervention in the heating system and can even be changed during the heating period. The valve built into the radiator is retained. This means that you do not need to switch off the heating or fear water damage by draining the heating water. Tenants should check the thermostat change with the landlord in advance.
With easily accessible radiators, the replacement does not take two minutes. A pipe wrench or a water pump pliers is normally sufficient as a tool, with which you can loosen the screw ring on the old thermostat. The fixing is usually done with a cap nut, less often by clamping screw or snap-on fastening. After loosening, the previous thermostat head no longer presses on the valve spindle and can be easily dismantled.
Plug in the new thermostat and tighten its screw ring by hand - done!