ENE 02 - Energy Monitoring - BREEAM Knowledge Base

Acceptable alternative strategies to sub-metering by floor plate - KBCN00071

An alternative sub-metering strategy, not based on a by-floor-plate basis, would be acceptable provided that: - it provides an equivalent, or more useful level of detail than sub-metering by floor plate. - it divides the assessment in a logical manner which provides useful information to building management re: energy use. - the approach does not conflict with requirements for sub-metering other functional areas. The intent of sub-metering by floor plate is to allow a large homogenous function (such as office space) to be split up into smaller areas that will allow building management to monitor, identify and influence areas of high energy use. Alternatives that also meet this intent are also acceptable.

Accessibility of energy metering systems - KBCN0580

Energy metering systems should be accessible and the energy consuming end uses visible to building users, such as the facilities manager, where present, and/or other building occupants responsible for the management of the building.

Assessment Part applicability - KBCN1165

The scope of this Issue is determined by the RFO Part(s) assessed. For example, in a Part 3 only assessment, compliance must be demonstrated only for local services. The same principle applies when assessing against Part 2 only, where only the core services need to comply. This Issue is not applicable to Part 1 or Part 4.

17.08.2018 Technical manual to be amended in the next reissue.

Centralised air handling units (AHU) - KBCN0941

The requirements of the:

Second sub-metering credit (New Construction).
Issue (BREEAM In-Use).

do not apply to centralised AHUs, where it is not technically feasible to sub-meter energy use by separate functional, tenanted or floor areas. The credit(s) will be assessed based on the remaining applicable energy uses.

06-Mar-2024 - Scheme applicability extended to V6.

Combined sub-metering – electric space / water heating and small power - KBCN00068

For bedrooms and associated spaces in:

Multi-residential or residential institution building types (New Construction).
Hospitality or supportive housing asset types (BREEAM In-Use).

It is acceptable for an electric space or water heating system to be combined with lighting and small power, provided that sub-metering is provided for each floor plate or other appropriate sub-division. For these asset types, sub-metering electric heating in multiple bedrooms may be costly and technically challenging. Where occupants have individual control but are not responsible for paying the utility bills, the building manager may have little influence on their energy consumption. Therefore, sub-metering electric heating would provide little or no benefit in meeting the aim of the issue.

06-Mar-2024 - Scheme applicability extended to V6. 
15-Dec-2023 - Title updated to clarify that this approach can be applied to both space heating and domestic hot water heating, where appropriate.

Combined system for heating / cooling and domestic hot water - KBCN0329

It is permissible to have combined metering for a shared on-site or district system that combines heating / cooling, and domestic hot water generation. In all cases, justification is provided in the QA report for the combined metering, and explains why it is not technically feasible to provide separate meters.

21-Sep-2022 Applicability of KBCN added to BIU V6. Amended to include district heating and cooling networks.

Definition of ‘total useful floor area’ - KBCN00079

The total area of all enclosed spaces measured to the internal face of external walls. In this convention:

The area of sloping surfaces such as staircases, galleries, raked auditoria and tiered terraces should be taken as their area on plan
Areas that are not enclosed, such as open floors, covered ways and balconies, are excluded

Energy monitoring and management systems and small useful floor areas - KBCN1361

The requirement for an energy monitoring and management system (Building Management System – BMS) applies to useful floor areas that are greater than 1,000 m². For developments where useful areas are monitored by single utility meters (of the same fuel) and are smaller than 1,000m², the BMS requirement is not applicable. This is because the value of monitoring given by a BMS is not appropriate for such small areas. For example, in a situation where a large building is served by several utility meters (of the same fuel), with none of them covering a useful floor area greater than 1,000 m², the requirement for BMS is not applicable.

Energy sub-metering – Single occupancy & function - KBCN0491

In large buildings of single occupancy/tenancy where there is only one homogeneous function (e.g. hotel bedrooms, offices), sub-metering should be provided per floor plate.

Head-end systems for smart meters - KBCN0933

As the central component in an Advanced Metering Infrastructure (AMI), head end systems allow data communication and collation from a large and disparate set of smart meters. Where smart energy meters and sub-meters are to be installed, a head-end system is required for any strategy utilising this technology to be considered for compliance.

Point of use water heaters - KBCN0773

Small 'point of use' water heaters can be excluded from the sub-metering requirements. Only major energy consuming systems that have a measurable impact on the operational energy consumption need to be included.

Self-contained dwellings or units with individual utility meters - KBCN0199

Where self-contained dwellings or units covered by the assessment have their own individual energy supply and utility meter (e.g. water, gas or electricity), this supply can be excluded from the scope of the issue. All shared energy supplies and common areas under the responsibility of building management are still included in the assessment. For example, if self-contained flats in an assisted living development have individual gas supplies with their own utility meter, this supply will be excluded from the assessment. However, the lighting and small power comes from a shared distribution board on each floor, in which case this shared supply will need to be sub-metered in accordance with the criteria. This same principle applies to scenarios involving speculative industrial or retail units with capped services, where these units have their own utility meter.

12/09/2018 Applicable to Water Monitoring Issue where appropriate
27/09/2017 The word 'units' added to include a wider range of scenarios falling under this principle.
17/06/2022 Added other industrial / retail situations for further clarity on the applicability of this KBCN.

Single functional area and no tenanted areas – operational energy monitoring - KBCN00056

Where the building has a single functional or tenanted area for sub-metering, with no other significant energy uses that must be separately metered, then:

The sub-metering of functional and tenanted areas credit can be awarded by default if,
The sub-metering by end use credit is achieved.

26-Mar-2024 - Wording clarified. Scheme applicability updated.

Space heating as major energy use - KBCN0939

Where possible, space heating should always be considered as a major energy use for sub-metering purposes. Where space heating cannot be separated from hot water, this must be fully justified by the design team at QA. See KBCN0329: Combined system for space heating/cooling and domestic hot water. Where electric space heating is used, this in itself cannot be used as justification for combining the space heating along with lighting and small power unless there is a clear justification for doing so. See KBCN0068: Combined sub-metering of electric heating and small power equipment.

Sub-metering at least 90% of each fuel - KBCN0657

In a scenario whereby several energy consuming systems are not sub-metered because they account for less than 10% of the annual energy consumption (see Ene 02 methodology), and this results in less than 90% of the estimated annual energy consumption of that fuel being metered, the M&E consultant should review the metering strategy and advise which of these energy consuming systems would most benefit from sub-metering to make up the 90%. This may be based on which of the energy consuming systems has the highest annual energy consumption, or which has the most potential for reducing energy consumption as a result of sub-metering. This will not necessarily have to mean that the energy consuming systems chosen have to have their own sub-meter, the M&E consultant may decide they would most benefit from metering alongside another consuming system. However ultimately 90% of each fuel must be metered. Justification should be given within the metering strategy and the BREEAM assessment report as to which lower energy consuming systems were chosen to be sub-metered to make up the 90%, and how this was done to best suit the development (i.e. individual sub-meters or paired with another consuming system).

Sub-metering by calculation - KBCN0700

For simple sub-metering strategies, it is acceptable to calculate a single end-use by subtraction of known, sub-metered end-uses from the relevant main utility meter reading. For more complex strategies, where a BMS/BEMS is used, the software should be capable of calculating and displaying all required end-uses in line with the criteria.

Sub-metering of high energy load and tenancy areas – existing building systems - KBCN1341

Where a refurbishment assessment contains existing systems which are impractical to retro-fit in accordance with the sub-metering criteria, a practical alternative metering strategy may be acceptable (see also KBCN00071). Where existing systems cannot be retro-fitted, however, the credit is not awarded by default; this does not meet the intent of the guidance for additional metering beyond a whole building approach. In all cases, suitable evidence should be provided to QA that demonstrates the inability to fully comply with the criteria, and that all practical means have been taken towards fulfilling the intent of the credit. In refurbishment projects it is not always practical to undertake significant retro-fits to existing building systems. Where such changes require disproportionate effort in relation to the scale and complexity of the project, BREEAM will accept more practical solutions that still meet the intent of the credit.

Sub-metering technologies – Compliance principle - KBCN1561

Where it can be demonstrated that alternative sub-metering technologies can meet or exceed the capabilities of systems set out in the BREEAM guidance, subject to approval, these can also be considered compliant. It is the role of the Assessor and the project team to provide evidence and justification in a compliance principle query (see KBCN1555). The following metering standards or technologies are currently recognized as alternatives to pulsed output meters:

M-bus. I.e. systems that comply with the EN 13757 series of standards. Also includes systems complying with the OMS (Open Metering System) standards.

Refurbishment and Fit Out / International / 2015 / 03 - Energy /

ENE 02 - Energy Monitoring