On-board metering

The Government has introduced changes to the Domestic RHI Regulations. Changes have been introduced in two stages. The first stage of changes to the Domestic Scheme came into effect on 20 September 2017. The second stage came into effect on 22 May 2018.

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

If you apply to the scheme with a heat pump on or after 22 May 2018, it must meet metering for performance requirements. There are three ways you can meet this requirement: standalone metering, on-board metering or a Metering and Monitoring Service Package (MMSP).

Some heat pumps have built-in or integrated meters and monitoring devices. If your heat pump has one or more integrated or on-board electricity meters, it can be used to monitor the electricity of the heat pump.

On-board electricity metering is likely to be purchased with your heat pump and integrated into it, rather than separate.

On-board electricity meters don’t have to meet the same technical specifications and accuracy requirements as standalone electricity meters. This will mean that the accuracy of this type of metering might be lower, but it still meets the minimum scheme requirements.

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.

Additional standalone metering would be required if on-board metering does not record and display input in any of the above cases which apply.

This will need to be added on your MCS Certificate.

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.

For more detailed information on metering, please see our Essential Guide to Metering.