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What's new in heating controls? A 2018 update

Posted by Sandra Hayes on 5 September 2018 at 9:17 am

We recently received a question about whether thermostatic radiator values (TRVs) had to be installed when a new central heating boiler was being installed. The reader wanted to know whether his heating engineer was correct to advise that TRV’s had to be fitted to all radiators, including the room where the thermostat was installed. 

To answer this question we need to look at the amendments that were introduced to the Government’s Domestic Building Services Compliance Guide on 6th April 2018.  This Guide introduced new minimum standards to meet the requirements of the Building Regulations on TRVs.  It also introduced additional changes known as Boiler Plus which require minimum energy efficiency standards and additional improvements when you have your boiler replaced.


Thermostatic radiator valves

As much as 60% of our domestic energy consumption comes from space and water heating. Thermostatic radiators valves control the flow of water through each radiator, meaning you can control the temperature of each room. This way you can ensure that you are not spending excess energy to heat a room that is hardly ever in use, or which you only pass through on your way to another area.

The EU Energy Performance of Buildings Directive (EPBD) was revised this year. It provides that individual room temperature controls such as TRVs do have to be installed in new-builds and in existing builds when the boiler is replaced. From 2006-2018, this had only been ‘good practice’, rather than mandatory for installers, although the majority of engineers did install them. Further information is set out in the Government’s Domestic Building Services Compliance Guide (2018 version).

This document states that during a gas or oil boiler replacement, space heating should be provided with “a room thermostat in a reference room served by the heating circuit, together with individual radiator controls such as TRVs on all radiators outside the reference room”.

However, if only certain components of the boiler or wet central heating system are being replaced, the installation of TRVs in every room except the reference room is described again as “best practice”, rather than a requirement. However, the benefits of TRV’s mean that most good heating engineers would recommend them in any event.

If the room thermostat is wireless and therefore has the ability to move between rooms, then it perhaps would be advisable to leave the wireless room thermostat in the room without a TRV.


Boiler Plus

From April 2018, all new boilers installed must have an ErP (Energy-related Products) efficiency rating of 92% or higher. As part of this legislation, all new gas and oil boiler installations must include a programme timer and a thermostat so that you can effectively control your heating (already a feature in most homes in the UK).

In addition, every gas and oil boiler installation must also include one additional energy-saving measure. There are four options that customers can choose from in conjunction with their heating engineer:

  1. Flue gas heat recovery systems – reuses excess heat from your boiler that would otherwise be wasted.
  2. Load compensating thermostat – modifies the radiator temperature to be hotter when your home is cold, and cooler when your home is closer to the desired temperature.
  3. Weather compensating thermostat - adjusts the radiator temperature depending on the outside temperature.
  4. Smart thermostat - allow you to control your heating in the same way as a programmable room thermostat, except through a tablet or smartphone, even when you’re not at home.

Those who expressed their frustration at Boiler Plus omitting the mandatory installation of TRVs during boiler and wet central heating installations will be relieved to see that this has now been recognised by the EU EPBD and the UK Government’s Domestic Building Services Compliance Guide.

As you will have noted neither of these initiatives require TRVs to be installed in the same room as the central room thermostat. If you have a wireless room thermostat then it would be beneficial to leave this in the same room where possible, without the TRV.




If you have a question about anything in the above blog, please ask it in the comments section below.

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1 comments - read them below or add one


ToffComment left on: 26 September 2018 at 11:22 am

A slight correction if I may. The Boiler Plus Regulations in relation to new gas boilers ONLY apply - as far as I am aware - to new combi boilers not system or heat boilers. There is a technical reason for this.

Moreover, despite the fact that UK legislation now makes provision for suppliers to use lodge ErP data with the UK Office for Standards and Safety, ErPs are ignored for EPC purposes unless the manufacturer has submitted the boiler/control to BRE for assessment. I have just had this ‘argument’ with BRE in respect of Honeywell Evohome zoned heating controls. For EPC purposes, it would seem that despite ErP giving a 5% efficiency saving, the EPC Database treats it as nothing more than two floor zones. There is a real danger of potential miss-selling here as the Govt and BRE appear not to be persuaded that smart heating controls offer much in the way of heating efficiency benefits. A simple online search will show that they may be correct as their is little in the way of empirical data.

 Edit for clarification:

Gas boiler performance: space heating efficiency of the new boiler no less than ErP 92% Time and temperature control required for all gas and oil boiler installations Combi boiler installations must also include one of the following: Weather compensation, Load compensation, Flue Gas Heat Recovery, Smart controls.

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