Operational carbon
‘Climate Emergency Design Guide: How new buildings can meet UK climate change’, published by The London Energy Transformation Initiative (LETI) in January 2020 defines Operational carbon (kgCO2e) as:
‘The carbon dioxide and equivalent global warming potential (GWP) of other gases associated with the in-use operation of the building. This usually includes carbon emissions associated with heating, hot water, cooling, ventilation, and lighting systems, as well as those associated with cooking, equipment, and lifts (i.e. both regulated and unregulated energy uses).
Net zero operational carbon refers to: 'A new building that achieves a level of energy performance in-use in line with our national climate change targets that does not burn fossil fuels and that is 100% powered by renewable energy.'
Embodied Carbon: Developing a Client Brief, published by the UK Green Building Council (UKGBC) in March 2017, defines operational carbon as: ‘Carbon emissions’ association with energy consumption (operational energy) while the building is occupied. This includes the regulated load (e.g. heating, cooling, ventilation, lighting) and unregulated/plug load (e.g. ICT equipment, cooking, refrigeration appliances).’
Improving Consistency in Whole Life Carbon Assessment and Reporting, Carbon Definitions for the Built Environment, Buildings and Infrastructure, Version ‘A’, May 2021, published by WLCN, LETI and RIBA, defines operational carbon - energy as: …the GHG (greenhouse gas) emissions arising from all energy consumed by an asset in-use, over its life cycle.’
It defines operational carbon – water as: ‘…those GHG emissions arising from water supply and wastewater treatment for an asset in-use, over its life cycle.’
BG 87/2024, Useful Information Guide, written by Chin Hang “Kay” Lam and published by BSRIA in 2024, defines operational energy or operational carbon as: ‘Energy used or carbon emissions generated during the occupation and use of a building by the heating, cooling, ventilation, water heating and lighting.’
[edit] Related articles on Designing Buildings
Featured articles and news
The sad story of Derby Hippodrome
An historic building left to decay.
ECA, JIB and JTL back Fabian Society call to invest in skills for a stronger built environment workforce.
Women's Contributions to the Built Environment.
Calls for the delayed Circular Economy Strategy
Over 50 leading businesses, trade associations and professional bodies, including CIAT, and UKGBC sign open letter.
The future workforce: culture change and skill
Under the spotlight at UK Construction Week London.
A landmark moment for postmodern heritage.
A safe energy transition – ECA launches a new Charter
Practical policy actions to speed up low carbon adoption while maintaining installation safety and competency.
Frank Duffy: Researcher and Practitioner
Reflections on achievements and relevance to the wider research and practice communities.
The 2026 Compliance Landscape: Fire doors
Why 'Business as Usual' is a Liability.
Cutting construction carbon footprint by caring for soil
Is construction neglecting one of the planet’s most powerful carbon stores and one of our greatest natural climate allies.
ARCHITECTURE: How's it progressing?
Archiblogger posing questions of a historical and contextual nature.
The roofscape of Hampstead Garden Suburb
Residents, architects and roofers need to understand detailing.
Homes, landlords. tenants and the new housing standards
What will it all mean?


















