When I upgraded my boiler in 2013 my gas consumption actually substantially increased. The reason for this is explained here and was caused having to heat the hall in the evenings whereas in previous years I did not.

This caused me to consider installing a fully zoned system as enabled by the use of the wireless Honeywell Evohome / Evotouch system where each room has to have reached its set temperature before the boiler is turned off.

This works by attaching programmable TRVs to each radiator. These talk to a central touch-controlled central controller - the Evotouch - where temperatures and time schedules can be managed. The controller 'talks' to a wall-mounted wireless controlled switch that turns the boiler on and off. Only when ALL the 'zones' are up to temperature is the boiler turned off.

It is even possible to have a separate wall-mounted or table-mounted sensor (DT92E) in a zone rather than relying on the one embedded in the programmable TRV.

A very useful set of FAQs can be found here including all the relevant user and installation guides.



This is the Evotouch controller that is used to configure the zoning system and to manage it on a day-to-day basis. It can handle 8 zones and can be 'bound' to the programmable TRVs in each zone and to the boiler control relay - the BDR91.

It is controlled by touch and has a wide range of facilities to control the temperature and timing in each zone ( it can have up to six time periods per day for each zone (radiator). Moreover, various optimisation techniques can be implemented to improve efficiency. The temperatures in all the zones compared to their set temperatures on a single screen.

This is the HR80UK wireless programmable TRV controlled by the Evotouch controller shown above. HR80UKs replace the mechanical TRVs on the radiators in each zone. The preset on/off periods (up to six are allowed) can be over-ridden with the control located on top of the TRV.

The system defaults to using the temperature sensor built into the programmable TRV but is also possible to bind the Evotouch controller to a separate wall-mounted DT92E thermostat in any zone.

This is the BDR91 wireless switch that the Evotouch controller uses to switch the boiler on and off as necessary. A green LED shows when the boiler is on and a red LED shows if the wireless connection to the controller faults.

This is the DT92E sensor that can be mounted on a wall or stood on a shelf. It is possible to bind one of these to the Evotouch controiller rather than using the sensor in the HR809UK. This provides a more accurate room temperature as the sensor is not located near the floor and near to the radiator which can lead to error.

I created eight zones and continued to use eTRVs in some rooms and the smaller secondary radiators in three of the larger rooms. I also added a programmable TRV - HR80UK - on the hall radiator so I have now returned to the system configuration before the boiler upgrade. All seems to be working well!

This the Evotouch controller showing the time scheduling menu - up to eight times per zone (room) can be programmed.
This is the overview of all eight zones showing the current temperature and the set temperatures once the house has come up to heat.

So far I am very pleased with the Evohome system and it works quite well in unison with eTRVs. It is really useful to be able to see the temperatures in each room and to be able to change the requested time schedules and temperatures from a single location. I have also acquired quite a few DT92Es through eBay and I place a table top mounted sensor in most rooms on the opposite side to that of the radiator to provide a more accurate set temperature in each room.


As can be read elsewhere, I have focussed on improving things in my home to enable me to redice my gas consumption:

As can be read elsewhere and building on my experience of using eTRVs in 20011/12, I have focussed on improving things in my home to enable me to reduce my gas consumption - to recap:

  1. Improving the insulation in my loft using the LoftZone product.

  2. I have upgraded my boiler to a more efficient model as can be seen on this page.

  3. I have added a Honeywell Evohome / Evotouch controller to add 8 zones to my house.

For the last thirty years I have only had the central heating on for twice a day ( 07:30 to 10:00 and 17:00 to 21:00) and only occasionally had it on for longer. The reason for this is that my gas usage shot up dramatically whenever I did this. Years ago, this didn't bother me as I just paid the bills without thinking. That is not the case now.

I have been using this regime for only a few weeks now but I AM AMAZED. I have been running the central heating system for 14 hours a day (07:30 to 21:00) and I am using less gas than I used before when running it for just twice a day! AND THIS IS STILL THE CASE IN JANUARY 2014.

BBC's Rory Cellan-Jones: Soaring energy bills - can smart technology help? He should come to my site to see that it does!