What is Open Therm?

Open Therm in simple terms is a communication protocol used in the central heating industry for communication between a thermostatic controller and a central heating boiler. Although Open Therm was developed by Honeywell in the 90’s, it is independent of any signal manufacturer. Open Therm allows for intelligent communication between the thermostatic controller and the boiler, with its primary feature being that it helps the boiler control the central heating temperature more accurately than basic ‘on, off’ thermostatic controllers.

What are the benefits of Open Therm Controls?

Open Therm Controls allow the boiler to maintain the heating temperature more accurately by limiting the temperatures the boiler puts into the radiators according to the set temperature and the actual room temperature. A common problem with standard ‘on, off’ controls is they allow the temperature to rise above the set point, and when the thermostat reaches temperature the radiators continue to heat as they have been running at temperatures usually in excess of 70C. The radiators then cool off and cause the thermostat to kick back in continuing the cycle of on, off, on, off. Along with this usually being uncomfortable for the home owner, it is also very inefficient, wasting gas as the boiler is constantly running at full rate for short periods on a constant cycle. Open Therm Controls on the other hand know that the radiators will continue to heat after the set temperature has been reached so they limit the radiator temperature at the optimal time, stopping the the room from getting too hot and stopping the constant ‘on, off’ cycle. On warmer winter days when the full power of the heating is not needed they will again limit the flow temperature helping to save on fuel costs and help to keep the house at the desired temperature.

Are Open Therm Controls compatible with my boiler?

Sadly Open Therm Controls are not compatible with all boilers. On the plus side most manufactures now build there boilers with Open Therm compatibility and also offer their own controls for this purpose. If you would like to know if your boiler is compatible we can give you that information and help with any queries you may have.

Are Open Therm Controls the same as Smart Controls?

Although many Smart Controls have Open Therm compatibility not all Smart Controls have this feature. Smart Controls are generally identified as being internet connected, energy saving controls but some will cut your fuel bills more than others. Some examples of Smart Controls with Open Therm that we fit regularly are the Honeywell T6 and the Nest 2nd Generation Thermostat. However Open Therm is not limited to Smart Controls and many brands offer simpler, more cost effective Open Therm Controls.

What do Open Therm Controls cost?

Open Therm Controls start at around £60 going up to £250.

How do I get an Open Therm Control installed?

Tom Sutton Heating is on hand to guide you through buying the right control for you and installing it to your needs. We can come to your property and check if your boiler and heating system is compatible, then give you a quote for the control of your choice. Drop us message on our inquiry form for more information.