03 - Energy - BREEAM Knowledge Base

Calculating EPR where there are multiple BRUKL/NCM outputs - KBCN1083

Where more than one NCM output is produced for a development, which is registered as a single assessment, an area-weighted average should be used to calculate the number of credits to be awarded. This does not apply where the ‘similar buildings’ approach is used. For for projects in England assessed under UKNC V6.0, please see KBCN1618 Projects assessed under UKNC V6.1 can upload multiple BRUKL.inp files for a single assessment and the platform will perform the calculation. See KBCN1618 Each energy performance output from the NCM output (actual CO₂/m² notional CO₂/m² etc.) must be area-weighted to produce area-weighted average values entered into the scoring and reporting tool. When applying this method, please include your area-weighting calculations and outputs as supporting evidence. The following provides an example of an area-weighting calculation for two building areas A and B, each of 500m², for which separate NCM outputs are available: For building area A: Notional building heating and cooling energy demand: 230 mJ/m² Actual building heating and cooling energy demand: 200 mJ/m² Notional building primary energy consumption: 300 kWh/m² Actual building primary energy consumption: 280 kWh/m² TER: 40 kg CO₂-eq/m² BER: 30 kg CO₂-eq/m² For building area B: Notional building heating and cooling energy demand: 150 mJ/m² Actual building heating and cooling energy demand: 140 mJ/m² Notional building primary energy consumption: 200 kWh/m² Actual building primary energy consumption: 190 kWh/m² TER: 40 kg CO₂-eq/m² BER: 38 kg CO₂-eq/m² Area-weighted values for building areas A and B (of total floor area 1000m²): Notional building heating and cooling energy demand: 230*500/1000 + 150*500/1000 = 190 mJ/m² Actual building heating and cooling energy demand: 200*500/1000 + 140*500/1000 = 170 mJ/m² Notional building primary energy consumption: 300*500/1000 + 200*500/1000 = 250 kWh/m² Actual building primary energy consumption: 280*500/1000 + 190*500/1000 = 235 kWh/m² TER: 40*500/1000 + 40*500/1000 = 40 kg CO₂-eq/m² BER: 30*500/1000 + 38*500/1000 = 34 kg CO₂-eq/m² These area-weighted values are then used to calculate the overall EPR_NC value.

20 Sep 2023 - Minor corrections, applicability to INC V6 confirmed and cross-reference to UKNC V6 guidance added.
14 Jun 2023 - Note added to confirm this is integrated into the platform for UKNC V6.1 in all countries. 
24 Aug 2022 - Note added to confirm this is N/A to UKNC V6 for projects in England
07 Feb 2022 - Reference to 'BRUKL' amended to 'NCM output' to clarify for non-UK assessments
31 Oct 2018 KBCN clarified. Reference to EPRs and calculation example added

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.

Erratum – up to V6 – checklist A5 – lighting - KBCN1629

Item 1 of Checklist A5 states:

This is incorrect. The requirements should be:

Non-day lit areas with intermittent occupancy must have occupancy controls.
Day-lit areas must have daylight detection controls.
The controls conform to either ASHRAE 90.4 or California Energy Code.

Escalators or moving walks – variable speed drive - KBCN1621

The requirements refer to 'a load sensing device that synchronises motor output to passenger demand through a variable speed drive'. The intent is that the inverter must operate full-time to moderate output based on passenger demand.

Excluding large untreated warehouse spaces from ‘Useful floor area’ - KBCN00069

For industrial buildings, where there are offices and the untreated warehouse space does not include any energy-intensive systems or processes, the warehouse space can be excluded from the calculation of 'useful floor area' to determine whether Criterion 2 or 3 (Criterion 2 only in UK New Construction 2018) is applicable. For speculative developments, if Planning Consent includes Distribution or Warehousing (UK Planning Use Class B8 or equivalent local planning consent) and the design team and assessor can justify that this is the intended use, the above approach can be followed for untreated warehouse space. Where there is minimal energy consumption, complex sub-metering such a space would add little benefit.

28 Oct 2022 - Applicability to INC V6 and UK NC V6 confirmed.
Wording clarified and note added relating to speculative developments - 16/12/2016
Wording clarified relating to speculative developments - 06/01/2020

Internationally approved Ene 01 calculation software - KBCN1177

The following calculation software are approved internationally and can be used, provided local weather files are available in the country of the assessment. Please make sure the approved version, in brackets, is used. If you wish to use a different one, please submit a technical query to [email protected] providing details of the changes.

IES VE (all versions from 2014 onwards).
Design Builder (version 4 onwards).
TRNSYS (version 17 onwards).
eQUEST (versions 3.63b and 3.64 onwards).
Energy Plus (version 3 and version 6 onwards).
EDSL Tas (v9.5.0 onwards).

Any software that has been approved on the ASWL for a particular country can be used in other countries, provided relevant weather files are available.

26-Mar-2024 - Scheme applicability updated.
08-Aug-2022 - Applicability to BREEAM Communities 2012 confirmed.
30-Jun-2023 - Added note relating to software approved for a particular country.

LZC – Local regulations and private wire arrangements - KBCN1658

Where local regulations do not permit electricity generated by on-site renewables to be connected directly to the building, and where evidence of the relevant regulations is provided at QA, the requirement for a private wire arrangement can be waived.

LZC technologies – Compliance Note 5 - KBCN1615

If electricity is generated from a renewable source and used directly in the heat pump system, this can be considered in this issue, providing the LZC source is on or near site.

On-site LZC – whole site shared connection - KBCN1424

To be recognised in BREEAM, the on-site Low and Zero Carbon (LZC) technology must have a direct physical connection to the assessed asset. OR Where the LZC technology is;

Located on the same site,
Is owned and managed by the same organization as the assessed building, and
Where it is impractical to physically connect the assessed building to the system,

It is acceptable to allocate the renewable energy generated proportionally as a calculation of the asset's predicted energy consumption compared to the total energy consumption of the whole site. To allocate renewable electricity by proportional consumption:

Obtain the total annual renewable electricity generated on-site.
Exclude all renewable electricity which has been exported to the grid.
Determine the respective electricity consumption of all assets on the whole site (predicted for new builds and measured for existing assets).

Where consumption data is missing, renewable electricity must not be allocated to the assessed asset. In this case, it is assumed that all electricity consumed is sourced from the grid.

17-Jan-2024 - Applicability BIU V6 Ene 13 removed, as this approach is not applicable to assessing the area of PV fitted.
21-Dec-2022 - Applicability to In-Use V6 confirmed.
24-Aug-2022 - Applicability to UKNC V6 confirmed.

Prediction of operational energy consumption – alternative route to Excellent minimum standard - KBCN1336

Where the ‘Prediction of operational energy consumption’ criteria are achieved, the minimum standard for Excellent in Ene 01 is met. This is independent of meeting any minimum credit score in the issue to achieve the Excellent minimum standard. See KBCN1602. Substantial improvement To meet this minimum standard, the asset must show a substantial improvement in operational energy performance, following the ’Prediction of operational energy consumption’ criteria. This 'substantial improvement' is defined as achieving 4 credits using amended metrics generated using the dynamic simulation modelling and for:

UK: the Ene 01 methodology that applies to your scheme version.
International: assessments using the Option 1 approach.

Amended definitions Performance is calculated based on amended definitions of an actual and a notional building: Amended actual building:

Actual fabric.
Expected actual occupancy.
Actual building servicing systems.

Amended notional building:

Notional fabric.
Expected actual occupancy.
Notional building servicing systems*.

*The notional building servicing system may be replaced with a gas boiler as the heat generation source. Where the performance improvement over the amended notional building does not achieve 4 credits, the BREEAM Excellent standard may still be met. Robust evidence must be provided showing that this level of performance improvement is not possible, based on constraints outside of the control of the project team. Additional notes for UK schemes Projects assessed under UKNC V6.1 can manually input amended figures from the modelling into the platform to demonstrate the 'substantial improvement'. See "DSM Alternative Ene 01 inputs" in BREEAM Projects for this issue. For the energy modelling and reporting criteria, the CO₂ metric can be calculated using either:

The CO₂ and primary energy factors for the Buildings Regulations version specified in UKNC 2018 / V6 or,
Using SAP 10.2 emission factors. The Government’s Standard Assessment Procedure for Energy Rating of Dwellings Version 10.2 (17-12-2021) https://files.bregroup.com/SAP/SAP%2010.2%20-%2017-12-2021.pd

08-Nov-2023 - Additional wording and link to KBCN1602 added to clarify situation for UK simple buildings.
26-Jun-2023 - Content updated to apply to International schemes. Title and wording clarified. Text on manual errata in NC 2018 3.0 moved to KBCN1602.
14-Jun-2023 - Note added to confirm this is integrated into the platform for UKNC V6.1 in all countries. 
24-Aug-2022 - Content updated and applied to UKNC V6
19-Aug-2019 - Clarification for UKNC 2018 3.0.

Scope of the criteria for lifts – Small service lifts (dumbwaiters) - KBCN1589

Small service lifts, of the type typically used to transport prepared food and crockery in restaurants (sometimes referred to as 'dumbwaiters'), fall outside the scope of this assessment issue.

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.

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 recognised 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.

New Construction / International / V6 /

03 - Energy