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What does Net Zero mean?

For the last 3 years LETI has been providing useful guidance on the requirements of buildings that align with our climate targets. In 2019 we developed the net zero operational carbon one pager, in 2020 we published the Climate Emergency Design Guide and the Embodied Carbon Primer, that brought in embodied carbon targets. Working with the WLCN, we refined and aligned our embodied carbon targets, developing consistent targets with RIBA and IStructE in the summer of 2021. We also published our Climate Emergency Retrofit Guide that outlines how existing homes need to be adapted to meet UK climate targets.

The new publications provide guidance on how to define good, when it comes to new buildings and retrofit of homes. But what does this mean in the context of ‘net zero carbon’. As an industry we need clarity on the definition on net zero carbon, this is provided in the Carbon Definitions for the Built Environment, Buildings and Infrastructure, which has been developed by the Whole Life Carbon Network (WLCN) in collaboration with LETI.  Crucially these definitions are based on meeting operational energy and embodied carbon targets and generating energy from renewable sources.

For the past few months we have therefore been working with CIBSE to develop Net Zero FAQs, which build on the definitions developed by WLCN-LETI in summer 2021 and look at whole life, embodied, and upfront carbon; operational energy; and operational water.

This guidance from LETI and CIBSE builds on the WLCN-LETI carbon definitions to try to make sure that the definitions are applied consistently and robustly in as many real-life situations are possible.

The CIBSE-LETI Net Zero FAQs are supported by RIBA, BRE, WLCN, Good Homes Alliance, IStructE and RICS.

How the FAQs were developed

First, we asked what industry wanted clarity on, (informing what questions the FAQs should answer) and then we sought to drive consensus on these issues by carrying out a consultation with LETI and CIBSE members and the wider industry.

Next steps

These FAQs do not provide a definitive answer to what Net Zero means, for all building types, but it is a step on the road and points towards a direction of approach to address common situations in many building types. Further work is needed and being planned in collaboration with other industry bodies to develop further clarity and consensus on Net Zero.

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LETI-CIBSE Net Zero FAQs Webinar 07.04.2022

Clara Bagenal George, LETI
Julie Godefroy, CIBSE
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