Virtually every day, newspapers and magazines are filled with reports of grand schemes to decarbonise the UK’s energy sector. Wind, solar, nuclear electricity generation, and ‘green gas’ scenarios hold the promise of a carbon-free home in the future. In all those cases, however, the amount of time needed for implementation on a large scale will be significant. 

We believe that the new generation of heating controls with open connectivity, using a point-to-point communication protocol such as OpenTherm, can realise carbon savings from existing heating systems, as well as facilitating further innovations in the future. 

We have hosted two online round table events in recent months that attracted sizeable audiences, mostly installers, keen to understand what OpenTherm offers and to hear from experts about its use and installation. These included Huite Jan Hak, the OpenTherm Association’s Technical Director, and two UK experts: Rob Whitney from Resideo, and Richard Burrows from, as well as myself.

There are several reasons why we all see the benefits of OpenTherm as a tool to decarbonising UK homes.


Firstly, the system allows boilers to operate at their maximum efficiency. Many installations in the UK are still using mechanical on/off room thermostats, or don’t even have a room thermostat at all. This results in boiler supply temperatures that are temporary, or continuously higher than required to provide a comfortable living temperature. 

The challenge is to operate the boiler at a supply temperature that is as low as possible, such that the maximum efficiency is realised. Current condensing appliances are modulating, with constantly improving ranges. 

We believe that the optimal solution for Boiler Plus load control is to use the modulation feature of today’s boilers to the maximum. We should use modulating controls for modulating boilers.


Secondly, heating appliances with open connectivity provide an installed base for innovative energy saving control solutions. The best example is the development of internet-connected ‘smart’ controls. 

Interestingly, it wasn’t the traditional control companies that first introduced this new generation of controls, but companies from the IT world, looking for useful applications of the emerging Internet of Things (IoT) technology. 

Features, like remote control with an app on your mobile and geofencing, can contribute to energy saving.

New developments include combinations of gas boilers, heat pumps, thermal and/or photovoltaic panels, where limiting the systems’ carbon footprint is still a challenge. Open connectivity incentivises innovation in that respect.

Better maintenance

Thirdly, equipment with open connectivity facilitates remote diagnostics. Aside from benefits in the logistics operation, and the reduction of costs, remote diagnostics assures that systems continue to work optimally during the lifetime of the equipment.


And, finally, freedom of choice for manufacturers, installers, and consumers bolsters competition and innovation. Thanks to OpenTherm, a heating appliance can be combined with a heating control from another brand, providing a system that fits the installation and the user’s requirements, all at the right price.

One protocol

OpenTherm is managed by the OpenTherm Association, which currently consists of 90 manufacturers of heating products come together to further the cause of open connectivity. 

The association was established 25 years ago, and the protocol has been updated continuously to broaden its application. 

Initially focused on gas-fired combi boilers, the protocol now also supports heat pumps, whole house ventilation, and thermal solar generation. 

Importantly OpenTherm is a ‘here and now’ technology, that is ready to help in the decarbonisation of existing UK homes. The system can be used to upgrade existing systems, increase their efficiency, and reduce energy consumption, in combination with improved insulation. 

Newbuilds will be able to adapt more easily to changes in technology, as the protocol evolves with the products on offer.