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CIBSE guidance to deliver net zero carbon buildings and how it relates to LETI

CIBSE has been actively working on climate change mitigation and adaptation and the links to building performance for two decades.

Overall recommendations for operational net zero carbon buildings

CIBSE recommends the following approach towards operational net zero carbon buildings:

  • Setting targets in energy use, which seek to minimise demand and energy use, and reflect the building’s performance independently from the grid. In addition, peak demand reduction and demand management should increasingly be considered to support the grid system and its decarbonisation.
  • Supplying that demand from low-carbon energy sources.
  • Only relying on off-site solutions as the last step, if needed, for additional carbon reductions.
  • Monitoring and disclosing performance in use.

For more detail on CIBSE recommendations towards net zero carbon buildings, see:

See also CIBSE’s Climate Action Plan for information on our overall activities towards net zero carbon; these cover policy and guidance, as summarised here, but also wider activities including research, education, and professional development.

New buildings

Nearly every new building constructed in the UK from now on will be part of the existing stock in 2050. CIBSE therefore proposes that all new buildings should be net zero operational carbon from 2030 and moving to a regulatory regime based on operational energy performance.

The London Energy Transformation Initiative (LETI) is a network of over 1000 built environment professionals working together to map the path to a zero carbon future. CIBSE has been involved with LETI from its initial stages. Following a wide ranging industry consultation LETI has prepared a one-page summary on the key features of Net Zero Operational Carbon new buildings. The development of the one-pager was supported by the UK-GBC, Better Buildings Partnership, Good Homes Alliance, RIBA, and CIBSE.

Retrofit

Retrofit across the existing building stock is essential for the UK to achieve Net Zero. CIBSE supports a detailed whole building approach to retrofit to deliver carbon savings, improve health and comfort in the home and avoid detrimental effects.

The LETI Climate Emergency Retrofit Guide provides a compelling argument for low-energy and low-carbon retrofit of the housing stock. CIBSE provided support and advice during the development of the LETI guide, and we look forward to continuing our work with LETI on this essential topic.

Work with CIBSE and LETI on retrofit - CIBSE and LETI will be working together on the Climate Emergency Retrofit Guide – Part 3, which will be focused on non-domestic buildings. Please contact CIBSE if you are interested in taking part.

Get involved

Get in touch (jgodefroy@cibse.org) if you would like to find out more, have comments, or would like to be involved with any workstream to continually update and develop CIBSE guidance on net zero carbon, for new and existing buildings and for retrofit projects.

CIBSE policies and guidance which support Net Zero Carbon

Net Zero definitions

LETI and the Whole Life Carbon Network produced a set of definitions in summer 2021.

Following engagement with members, CIBSE have made the decision to adopt the WLCN-LETI definitions.

In addition, CIBSE and LETI have been working to produce a set of FAQs to accompany the definitions and make sure they are applied consistently in as many real-life situations are possible. 



 Get your copy of the CIBSE LET Net Zero FAQs below (please allow a few seconds for the download link to appear after submitting)
Select the circles for a brief summary of CIBSE's position on each area or go to the boxes below for details of CIBSE positions and relevant guidance (View/Download LETI one-pager as a PDF).


Full details of the key relevant policy positions and guidance from CIBSE relating to the headings in the one pager above can be found below. This page is updated as our guidance develops, so please check it regularly.  Much of CIBSE guidance is dedicated to designing, operating and maintaining energy efficient and low-carbon buildings. It is therefore not possible to list all relevant guidance here.

LOW ENERGY USE AND DEMAND MANAGEMENT

CIBSE recommends setting targets for energy use during the operation of a building, alongside any carbon targets, in order to reflect the energy performance of the building independently from the carbon content of the energy systems which supply the building. This could be in Energy Use Intensity (EUI-kWh/m2/yr), or as targets which take some account of contextual factors, such as DEC ratings, or base building NABERS ratings (as per Note 2 in the LETI one-pager).

Specific targets may evolve as practice develops and as more data is gathered and shared, hence the importance of measurement and verification.

How do industry Net Zero targets relate to CIBSE guidance and projects in use?

For an illustration of how industry targets (e.g. LETI, RIBA 2030 Challenge) relate to CIBSE energy benchmarks in offices, see this webinar (slide 30).

For an analysis of how industry targets (e.g. LETI, RIBA 2030 Challenge) relate to CIBSE Awards projects, see this article: https://www.cibsejournal.com/general/making-data-count/.

Additional useful information is found throughout CIBSE guidance e.g.:

- CIBSE TM67 Electrification of Buildings for Net Zero, launched 2nd November 2021. You can view the recording and slides here: https://www.cibse.org/growyourknowledge
CIBSE TM60, for measures in the housing sector
CIBSE AM11 and TM54 on modelling and energy prediction - a 2022 revision of CIBSE TM54 was published in January 2022. We will separately create a body of case studies to accompany it. Do get in touch if you would like to contribute to these case studies. 
CIBSE Guide H on controls – planned revision.‚Äč

CIBSE supports demand reduction and management measures. Following the publication of TM67 in November 2021, our working group on electrical engineering towards net zero carbon will be working on more detailed guidance on topics such as peak demand reduction, demand management (including storage), integration of buildings and vehicles, interactions with the energy system, and more generally to support the electrification of buildings. Get in touch with our Head of Sustainability Julie Godefroy at jgodefroy@cibse.org for more information or to get involved.

LOW CARBON ENERGY SUPPLY

CIBSE supports the approach of minimising the use of fossil fuels and maximising on-site renewable energy generation.

Policy positions:
- Hydrogen: CIBSE response to 2021 consultation on a low-carbon hydrogen standard
- Heat Strategy: CIBSE response to 2018 heat framework consultation
- Heat Networks: CIBSE response to 2021 consultation on Green Heat Networks Fund

Guidance on low-carbon systems:

Hot water temperatures: In 2019 we set up a working group on guidance to facilitate energy savings and the integration of low-carbon sources, while ensuring health and safety (including addressing legionella risk). This led to the publication in August 2021 of a Guidance Note on domestic hot water temperatures from instantaneous HIUs, which aims to provide clear guidance to support practitioners in the delivery of lower carbon, safer and more reliable domestic hot water. Get in touch with our Head of Sustainability at JGodefroy@cibse.org if you would like to be involved with the next stages of work, including systems with storage.

Electrification of heat:
CIBSE TM67 Electrification of Buildings for Net Zero, launched 2nd November 2021. You can view the recording and slides here: https://www.cibse.org/growyourknowledge.
- CIBSE has set up a new working group on electrical engineering for net zero, whose work will support heat decarbonisation. Following the publication of TM67 in November 2021, the group will be working on more detailed guidance on topics such as peak demand reduction, demand management (including storage), integration of buildings and vehicles, interactions with the energy system, and more generally to support the electrification of heat and buildings. Get in touch with our Head of Sustainability Julie Godefroy at jgodefroy@cibse.org for more information or to get involved.

Heat pumps:
- New guidance AM16 Heat pump installations for multi-unit residential buildings, launched 4th November 2021. You can view the recording and slides here: https://www.cibse.org/growyourknowledge.
- Individual domestic heat pumps: guidance as part Domestic Heating Design Guide, 2021
Guide B1 1.7.9
TM51 ground source heat pumps: revision being planned under the upcoming AM17
CP2 surface-water heat pumps
CP3 open-loop groundwater heat pumps 

Biomass: Guide B1 1.7.6, AM15 - note that biomass installations are not recommended where air quality is a concern e.g. urban areas and Air Quality Management Areas. In the long-term they are also not in line with the recommendations of the Committee on Climate Change, which would prioritise the use of biomass for large-scale centralised installations with carbon capture and storage.

Solar thermal: Guide B1 1.7.11, HVSH Solar heating design and installation guide

PVs and solar thermal: KS15 Capturing solar energy.

Heat networks: CIBSE acknowledges that there are situations where schemes may be required to connect to an existing heat network which still relies on fossil fuels (e.g. for planning requirements), or where a heat network may open opportunities for decarbonisation of a surrounding area (e.g. in historic districts where the scope for building interventions is more limited). This should be thoroughly assessed on a case by case basis, to avoid continued long-term reliance on fossil fuels.

The assessment should include a comparison with other options, based on expected carbon performance on a like-for-like basis (not relying, for example, on arbitrary factors which artificially support some options, such as used in Part L calculations).  Connection to the network should also be on the condition of a clear and reliable plan for the network to transition to fossil fuel-free sources in the future. See also our policy response above, which sets out our position on how new and existing heat networks should be assessed.

Hydrogen:
- CIBSE is contributing to strategic industry guidance on hydrogen. See also our consultation response above on what a low carbon hydrogen standard should entail.
- Our Air Quality working group is preparing a briefing note on the air quality impacts of hydrogen combustion.

MEASUREMENT AND VERIFICATION

CIBSE has long advocated post-occupancy monitoring and disclosure of energy use. In-use performance data is required to apply for CIBSE awards. In 2019 we signed the cross-industry Building Performance Network statement asking for regulations and disclosure of in-use performance. CIBSE members can support this by signing the statement and/or monitoring and disclosing the performance of their offices.

The submission of post-occupancy data is a requirement for the CIBSE awards.

CIBSE publishes online energy benchmarks based on in-use data. Future phases will allow more frequent revisions and include more features e.g. new categories, visualisation of projects or portfolios against overall distribution. For more information and to contribute data, get in touch with our Head of Research Anastasia Mylona at amylona@cibse.org.

For an illustration of how industry targets (e.g. LETI, RIBA 2030 Challenge) relate to CIBSE energy benchmarks in offices, see this webinar (slide 30).

For an analysis of how industry targets (e.g. LETI, RIBA 2030 Challenge) relate to CIBSE Awards projects, see this article: https://www.cibsejournal.com/general/making-data-count/.    

Additional information on how to assess, fine-tune and improve performance is found throughout CIBSE guidance e.g.
CIBSE Commissioning Codes
CIBSE Guide M on maintenance engineering & management
TM61 Operational Performance of Buildings, 2020
TM62: Operational performance: Surveying occupant satisfaction, 2020
TM63: Operational performance: Building performance modelling and calibration for evaluation of energy in-use, 2020
TM64: Operational performance: Indoor air quality - emissions sources and mitigation measures, 2020
TM39: Building Energy Metering - in revision
TM23 Airtightness testing in Buildings - revision published January 2022. Watch a recording of the launch webinar here

REDUCING CONSTRUCTION IMPACTS

CIBSE supports attention to reducing embodied carbon impacts from building services. There are many opportunities for strategies that reduce both operational and embodied carbon, particularly when reducing peak and annual demand, and associated plant requirements.
Guidance:
CIBSE TM56 Resource Efficiency of Building Services, 2014
CIBSE TM65, Embodied Carbon in building services: a calculation methodology, 2021
CIBSE TM65.1 , Embodied carbon in building services: residential heating, 2021. Watch the launch webinar here

CIBSE recommends their members request Environmental Product Declarations (EPDs) for key items of plant when liaising with potential suppliers and manufacturers, in order to support the development of more widespread EPDs and more robust and consistent comparisons of embodied impacts. Where EPDs are not available, CIBSE TM65 sets out a recommended approach depending on the level of information available. We encourage the calculations done according to TM65 to be sent to CIBSE, as we will be collating it and creating a database for use by all. The forms associated with TM65 can be accessed here.
https://www.cibse.org/TM65/reportingform
https://www.cibse.org/TM65/manufacturerform

Upcoming guidance:
CIBSE is supporting research projects on embodied carbon, and further guidance is expected in the near future as a result.

Get in touch if you would like to be part of our upcoming working group on embodied carbon in building services.

ZERO CARBON BALANCE

CIBSE supports the approach that reliance on off-site carbon reductions should be minimised, and reductions should be demonstrated to be truly additional.