The built environment

The built environment represents almost 40% of global energy-related carbon emissions. The UK’s built environment is responsible for 25% of the UK’s greenhouse gas emissions[1]. It is therefore crucial that we tackle this sector’s emissions in order to limit global warming to a 1.5°C increase from pre-industrial temperatures and achieve net zero by 2050.

Embodied carbon vs. operational carbon

The carbon emissions associated with buildings can be split into embodied carbon, the carbon emissions associated with materials and construction processes throughout the whole lifecycle of a building, and operational carbon, the emissions associated with a building’s energy consumption. A net zero building needs to address both of these emission sources.

Net Zero buildings

The WGBC defines a net zero embodied carbon building (new or renovated) as “highly resource efficient with upfront carbon minimised to the greatest extent possible and all remaining embodied carbon reduced or, as a last resort, offset in order to achieve net zero across the lifecycle.”



According to the WGBC, net zero operational carbon is “when the amount of carbon dioxide emissions associated with building operations on an annual basis is reduced to a level that is consistent with reaching net zero at the global or sector level in 1.5°C pathways. Any residual emissions that remain unfeasible to eliminate should be neutralised through carbon removals”. 

The UKGBC Net Zero Carbon Buildings Framework defines two approaches to net zero carbon which are treated with equal importance: 

UK Policy – Operational carbon

Energy Performance Certificates (EPC) and Minimum Energy Efficiency Standard (MEES)

The UK Government is aiming for all non-domestic rented buildings to meet an EPC B rating by 2030. The current minimum requirement is E, with landlords prohibited from granting new leases of non-domestic privately rented property with an EPC rating below this. From April 2023, the ban will be extended to prohibit the continuation of any existing lease of non-domestic properties in England and Wales with an EPC rating below E.

The Government’s target is for most domestic properties to meet an EPC C rating by 2030. Since April 2020, landlords are banned from letting or continuing to let domestic properties with an EPC rating below E. The Government have announced changes to MEES for England and Wales, with all rental properties required to meet a C rating or above by 2025.

National performance-based policy framework for assessing energy use and carbon emissions

There is currently no correlation between EPCs and the actual operational energy consumption and associated carbon emissions of a building[1]. The popular and effective National Australian Built Environment Rating System (NABERS) considers buildings’ actual impact based on consumption data, building size and hours of occupation. BBP have recently launched a NABERS UK voluntary scheme for office buildings to calculate impact using a performance-based approach.

In line with the NABERS schemes, the UK Government has set out plans to introduce a national performance-based policy framework for assessing energy use and carbon emissions in commercial and industrial buildings above 1,000m² in England and Wales, with annual ratings and mandatory disclosure as the first step. This is expected to be launched in 2022, with mandatory public reporting coming into place by 2023. This framework complements the Non-Domestic Private Rented Sector Minimum Energy Efficiency Standards.

UK Policy – Embodied carbon

To date, policy has focused on reducing operational energy emissions through optimisation and renewable energy sources. At the moment, policy does not require embodied carbon emissions to be assessed or controlled and measurement and mitigation of these emissions is typically voluntary. The UK Government is aware of this issue and has recently committed to examining the standardisation of embodied carbon and whole-life assessments in their 2022 report, Building to net zero: costing carbon in construction.

https://www.ukgbc.org/wp-content/uploads/2021/11/UKGBC-Whole-Life-Carbon-Roadmap-A-Pathway-to-Net-Zero.pdf