BEIS launch new Boiler Plus legislation

New government legislation, Boiler Plus, brings amendments to Part L of the Building Regulations which will change the minimum requirements that heating engineers must meet when fitting boilers in existing buildings in England.

Julian Hodgson, Stroma Certification Technical Assessor, explains the new legislation which comes into effect on 6th April 2018.

What is Boiler Plus?

Introduced by the Department of Business, Energy and Industrial Strategy (BEIS), Boiler Plus is an additional legislation to Part L of the Building Regulations.


It sets out new requirements for heating engineers fitting new boilers and heating controls, with the aim of reducing domestic carbon emissions and encouraging energy efficiency. Boiler Plus applies to the minimum requirements of installing boilers in existing buildings in England only as of 6th April 2018.

The additional legislation will be:

  • Any gas boilers installed or replaced in existing dwellings must be a minimum of 92% efficient under the ErP European rating system.
  • Boiler interlock, time and temperature control must be present and operational for all boilers if they are new or replacements or upgrades. This also applies to oil boiler replacements. In the past, existing controls, or the lack of them, could be left in place. Although, best efforts should have been made to upgrade to current standards. In future, it will be mandatory for all new and replacement boilers to have time and temperature control.
  • When replacing a gas-fired combination boiler, at least one of the following options must be specified and installed:
    • Flue Gas Heat Recovery (FGHR)
    • Weather compensation
    • Load compensation
    • Smart thermostat with automation and optimisation

Changes to Part L of the Building Regulations (Boiler Plus) specify the new requirements heating engineers must follow when installing a boiler in a domestic property in England.

From April 2018, any system having a new or replacement boiler fitted must also include time and temperature control for all gas and oil-fired boiler installations. This could be achieved by the use of a room thermostat and programmer or a programmable room thermostat.

Please also refer to the Domestic Building Services Compliance Guide 2013. This states that the maximum area 1 heating zone can cover is 150 square meters. Larger properties with a living area greater than 150 square meters must have at least 2 zones with time and temperature control assigned to both.

Living and sleeping areas must be divided into separate heating zones, with a third zone for domestic hot water where applicable. All heating and hot water zones must have their own time and temperature control.

Please refer to Table 3 on page 18 of the Domestic Building Services Compliance Guide for more information on zoning requirements. This guide can provide crucial information and guidance for heating engineers as well as specifiers and enforcement authorities and will be updated to reflect these changes.

Gas Fired Combination Boiler requirements

Gas fired combination boiler installations make up approximately 75% of the UK boiler installations market. Where any new gas fired combination boiler is installed, be it a completely new installation or a boiler change or upgrade, the control system must also be upgraded to give interlock if this is not already present. The installation must also include either weather compensation, load compensation, a smart thermostat with automation and optimisation or FGHR system even if any of these measures were not present with the original combination boiler.

The first requirement is clear. It has been a requirement for all gas and oil-fired heating systems to have a full interlock for some time. The legislation which has been introduced concerning the replacement of existing boilers will bring the benefit of reduced carbon emissions.

The second requirement is slightly more complex. Where a gas-fired combination boiler is installed, an additional energy efficiency measure must be installed along with boiler interlock. The 4 measures are:

  • Weather compensation
  • Load compensation
  • Smart thermostats
  • FGHR

The first 3 measures are additional controls, whereas FGHR makes the boiler more efficient through using recycled heat from the flue gases to pre-heat cold weather prior to it entering the boiler.

Flue Gas Heat Recovery Systems

FGHR systems can be integral to the boiler or an additional attachment which is fitted at the time of installation. They are appliance specific and not usually inter-changeable between boilers. They take advantage of recovering heat from the flue gases created by the combustion process within the boiler. The recovered heat is then used to pre-heat the cold water entering the boiler, thereby reducing the amount of gas required to be burnt to raise the temperature of the cold water to its operating temperature which is set by the user and boiler controls.

FGHR systems are the only non-electrical additional efficiency measure and do not require any electrical qualifications to install. They must be installed in accordance with the manufacturer’s installation instructions by a registered competent person (e.g. a Gas Safe registered engineer with CEN1 and CPA1).

Weather Compensation System

This measure works by monitoring the outside weather temperature via an external temperature sensor. Using this temperature information, the controller will then adjust the temperature of the heated water going to the heat distribution system (radiators or underfloor heating). As the outside temperature drops, the temperature of the heating system water is increased. As the external temperature increases, the temperature of the heating water decreases thereby saving energy and reducing bills and carbon emissions.

Load Compensation

This measure adjusts the temperature of the water going to the heat distribution system. When a property is cold, the temperature is high. As the property warms up, less heat is required and the load compensation system will reduce the water temperature being delivered to the heat distribution system. This ensures comfort is maintained but less fuel is used.

Smart Controls with Automation and Optimisation

Smart heating controls are becoming increasingly popular due to their energy saving benefits and the flexibility they can offer to the customer as they can be controlled by a smartphone, PC or laptop. They can be programmed to turn on or off remotely and can also incorporate and optimiser. Optimisers work out how long it takes a property to reach its comfort temperature setting as specified by the householder. It can then automatically turn on the heating system so that the house will be at the required temperature at the specified time. Automated heating controls can work out when to turn on the heating based on whether the building is in use or whether someone is near.

The following flowchart was produced by the Heating & Hotwater Industry Council (HHIC) to help engineers choose the correct option.

Additional guidance

Please refer to the following documents and guidance for further information on Boiler Plus.

BEIS Boiler Plus FAQs
BEIS Heat in Buildings: Boiler Plus
Planning Portal Approved Documents

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