KNX in practice: Solution examples > Temperature control with KNX and OpenTherm

Brochure on KNX home and building control

On nearly 90 pages, you will find practical solution examples around KNX home and building control that are worth knowing.

KNX-Brochure_web ( 6.53 MB )

ETS example 5: Room climate control with KNX and OpenTherm

You can download the preconfigured project as a knxproj. file at this link:

ETS-example-5_KNX-heating-control-with-interface-to-OpenTherm ( 4.68 MB )

MIX2 actuators: intelligent, flexible, expandable

In an easily understandable way, our MIX2 videos show you the various advantages of the MIX2 series.

KNX Products from Theben

You will find a list of all KNX products of Theben here.

Needs-oriented and energy saving temperature control with KNX and OpenTherm

We still use most of the energy for heating. Even if the share in private houses is higher than in functional or administrative buildings: In both cases, the lion's share of energy costs is consumed by heating.

Inside the individual rooms, we control the temperature with valves, room thermostats, and presence detectors. In this way, energy savings of up to 6 % can be achieved by lowering the room temperature by only one degree in unoccupied rooms. The heating system itself does not respond to changes of this kind. It provides heat, no matter if it is currently needed or not.

Theben has gone one step further. With a needs-oriented heating control from the individual room up to the boiler.

KNX-Klimaregelung mit OpenTherm und KNX Grafik

Theben now bridges the world of heating and KNX home and building automation. With the KNX-OT-Box S interface, Theben establishes the connection between both systems.  With this, consumptions can be displayed in the KNX visualisation. However, the decisive  advantage is the direct access to the central heating control.

In this way, the flow temperature can be optimally set in a needs-oriented manner. By taking all rooms into consideration. Even more: The energy-optimised legionella protection prevents unnecessary heating of the storage tank to the legionella protection temperature. The effect: maximum energy savings. This is not only good for our environment, but also  for your wallet.

Flexible: Combined with the RAMSES 856 top2 OT heating control, even boilers without  OpenTherm interface can be completely integrated into the KNX installation.

Benefits at a glance

1. Needs-oriented individual room control

The KNX-OT-Box S not only allows pilot room control, but also needs-oriented flow optimisation  by considering all rooms.

2. KNX controls boilers

Due to the direct access from the KNX system to the OpenTherm boiler, the boiler cannot only be  visualised, but its complete control can be accomplished by the KNX system. In combination with  heating controller RAMSES 856 top2 OT, it even works with boilers without OpenTherm interface.

3. Energy saving domestic hot water

Heating domestic hot water with a solar power system helps save energy, as for instance the amount of sunshine expected according to weather forecasts can be taken into account for domestic hot water. Beyond that, the energy-optimised legionella protection prevents unnecessary heating of the storage tank to the legionella protection temperature.

Products for climate control with KNX and OpenTherm

KNX-Wetterprognose-Empfaenger Meteodata 139 KNX

Weather forecast receiver Meteodata 139 KNX*:

predicts what the weather will be like

The weather forecast receiver considerably contributes to minimise heating costs, to use sunshine and heat effectively, and to control  the sun protection with foresight. From HKW, it receives licenced  weather forecasts for the next three days via long wave. In this way, Meteodata 139 KNX* can tell whether the weather will be "fine", "cloudy", "rainy", or "stormy". Via telegram, the receiver sends the data to the corresponding KNX actuators, which – depending on the weather – control blinds, lighting, or, as in this case, the heating with foresight.

*This service is not available in all European countries. Find out more at www.efr.de/en

Technical data Meteodata 139 KNX*

Actuator CHEOPS control KNX:

allows maximum energy savings

This motorised actuator can virtually think: It controls heating valves and room temperature very precisely and stepless – easily recognisable via the LED visualisation. If the window is open, it switches off the heating. During an automatic calibration traverse, it recognises the most common valves. It only needs a bus line, but no actuator. This simplifies installation, avoids additional cables and pays off in daily use by optimum energy usage.

Technical data CHEOPS control KNX

KNX-OT-Box S:

builds a bridge to the world of heating

Two field buses, one installation – the connection in between is this little box, which enables the bidirectional exchange of data between the OT boiler and the heat distribution via the KNX system.  The KNX-OT-Box S allows needs-oriented and weather-compensated  flow control, control of domestic hot water, and much more. It even provides a legionella protection program. As practical as with the MIX2 actuators: Also here, the KNX bus module can be removed, replaced and programmed, independently of the device.

Technical data KNX-OT-Box S

KNX visualisation theServa:

more convenient, faster and easier control

theServa must be experienced – either on a smartphone or a tablet. The guiding principle during its development was: "Easy to use". With  a simple configuration, the user can set up floor plan and KNX  installation, and store them with about 250 preprogrammed switch  elements. The time switch can also be operated via a rotary knob – for all calendar functions or presence simulation. theServa provides  a completely new experience of buildings.

Technical data theServa

Consideration: Connecting worlds

Schnittstelle zwischen KNX und OpenTherm: KNX-OT-Box S

The Theben KNX-OT-Box connects the OpenTherm bus, commonly used with gas heaters, with the KNX bus. The advantage: The boiler cannot only be  visualised in the KNX system, but can be completely controlled by the KNX system.