Installers and metering

Subject to parliamentary approval, new regulations will be coming into effect in spring 2018. For information on what the Government changes mean for you, please see our webpage changes to the scheme.

The Government is introducing changes to the Domestic RHI Regulations. Changes are being introduced in two stages. The first stage of changes to the Domestic Scheme came into effect on 20 September 2017. 

The second stage of regulations were laid on 7 February 2018. These new regulations will come into effect subject to parliamentary approval. The parliamentary process usually takes 6 to 8 weeks; not including any recess time. 

For more information about changes to the scheme and what they mean to you, please see our changes to the scheme webpage and Factsheet: Important Changes to the Domestic RHI Scheme

As an installer you need to know when, under the Domestic RHI scheme, a system must be metered for performance and/or when a system must be metered for payment, how these types of metering work, and what metering documents you need to complete and give to your customer for their application.

Solar thermal for heating domestic hot water never has to be metered. If that’s all your customer has installed, you don’t need to read this page. 


Where systems need to be metered for payment

Below we’ve highlighted some common situations which do require metering for payment, but for full details make sure you read our Essential Guide to Metering.

1. Where there’s back-up heating

This applies where:

  • The renewable heating system is installed alongside a fossil fuel space heating system. For example, where there’s a biomass boiler and a back-up oil boiler;
  • The renewable technology is a heat pump with an integrated fossil fuel system, like a gas boiler, built into it; 
  • There’s more than one renewable heating technology for space heating, for example, where there are two biomass boilers. See multiple products (open key pop up term) for more information. (Remember that it’s fine to have a solar thermal plant installed alongside your other technology, as long as it’s only heating domestic hot water).

Back-up heating that doesn’t count: The system doesn’t need metering if the back-up heating is only designed and installed to heat a single room, such as an open fire or plug-in electric heater. Similarly, immersion heaters and supplementary electric heaters, that some heat pumps and biomass systems have, don’t count. Heat recovery systems that recycle air but don’t generate additional heat also don’t need to be metered.

2. Where there’s a biomass heating system that isn’t designed to heat the whole property

Biomass systems must meet all of the space heating requirements for the property. If this is not the case then the system will need to be metered.

3. Where the property is occupied for less than half the year

Homes that have been lived in for less than half the year must be metered. This includes second homes or tenanted properties, which have been empty for 183 days in the 12 months prior to applying to the scheme. The applicant needs to declare on the application form if their home is occupied for less than 183 days a year. If your occupancy drops below 183 days in any 12 months after your accreditation, you may also require metering for payment. This rule doesn’t apply if the applicant is applying as a custom build.

Where systems need to be metered for performance

This section only applies if your customer has a heat pump. If they don’t have a heat pump then go to the metering for payment section to see if their renewable energy plant needs to be metered for payment.

When new regulations come into force, it’s a requirement that all new applications for air source and ground source heat pumps must have electricity metering arrangements alongside their heating systems to be eligible for the Domestic Renewable Heat Incentive (RHI).

There are three metering arrangement options available for metering for performance:

  1. Stand-alone electricity metering
  2. On-board electricity metering
  3. Metering and Monitoring Service Package (MMSP)

The meter(s) will be required to record and display:

  • electricity used by the plant to generate heat;
  • electrical input into any supplementary electric heater controlled by the same control system as the heat pump; and
  • electrical input into any immersion heater for a domestic hot water cylinder where the immersion heater is controlled by the same control system as the heat pump.

This will need to be added on your MCS Certificate. For full details and examples, please read our Essential Guide to Metering.

Note: If there are multiple supplementary or immersion heaters controlled by the same control system as the heat pump, a single meter can be installed to record the total combined electrical input; or, each heater can be metered separately. Metering input to each heater separately could help identifying if there is an issue with an individual immersion heater/supplementary heater.

Publications and updates

  • Published: 1st Sep 2017
  • Guidance
  • 1 Associated documents
Installers must complete installer metering questions for people who have heat pumps for the Domestic RHI.

  • Published: 23rd Aug 2017
  • Guidance
  • 1 Associated documents
Installers must complete an alternative metering arrangement form for Domestic RHI applicants with biomass.

  • Published: 23rd Aug 2017
  • Guidance
  • 1 Associated documents
Installers must fill out an alternative metering arrangement template for Domestic RHI applicants with heat pumps.

  • Published: 23rd Aug 2017
  • Guidance
  • 1 Associated documents
Installers must complete Installer Metering Questions for people with a biomass heating system in the Domestic RHI