Targeting Net Zero


Achieving Net Zero Through Retrofitting in the City of London

The City of London, with its blend of historic architecture and modern infrastructure, faces a unique challenge in meeting net zero carbon targets. Retrofitting existing buildings is a crucial strategy, balancing the preservation of heritage with the adoption of cutting-edge technology. This was the ambition at our project on Ludgate Hill for developer HubCap and Bridges Fund Management.

Standards & Regulations

Several standards and regulations guide the pathway to net zero. The UK Green Building Council (UKGBC) sets a framework for achieving net zero carbon in construction and operation. The Building Research Establishment Environmental Assessment Method (BREEAM) provides a robust method for assessing buildings. Additionally, the London Plan includes policies specifically aimed at reducing carbon emissions from the built environment.

Ludgate Hill CGI © Studio Archetype

Heritage Challenges

Retrofitting in the City of London must navigate the complex landscape of heritage conservation. Many buildings are listed or situated within conservation areas, requiring careful planning and collaboration with heritage bodies such as Historic England. The challenge is to upgrade these structures without compromising their historical value. Innovative solutions, such as internal insulation or discrete renewable energy installations, are often necessary to preserve the aesthetic and structural integrity of heritage buildings.

Historic image of Ludgate Hill © Unknown

Operational vs. Embodied Carbon

A significant consideration in retrofitting is the distinction between operational and embodied carbon. Operational carbon refers to emissions from the building's day-to-day energy use, while embodied carbon encompasses the emissions associated with the building's materials and construction processes. Retrofitting aims to reduce both: improving energy efficiency through better insulation and intelligent systems and selecting low-carbon materials to minimise the embodied carbon footprint. At Ludgate Hill, we targeted a reduction of 35% of on-site carbon emissions through thermally upgrading the building fabric - including replacing the aluminium framed, single-glazed windows and more efficient, electric-only building services.

Technological Improvements

Advancements in technology play a vital role in achieving net zero. Energy-efficient HVAC systems, LED lighting, and intelligent building management systems reduce operational carbon. Innovations such as phase change materials for thermal storage and advanced glazing systems enhance building performance. Additionally, integrating renewable energy sources, like solar panels and ground source heat pumps, is becoming more feasible even in dense urban areas.

Window detail at Ludgate Hill © Holland Harvey

Offsite Credits

Offsite credits offer a way to compensate for unavoidable emissions. These credits can be purchased to support renewable energy projects or reforestation efforts elsewhere, effectively balancing the carbon ledger. While not a substitute for direct emission reductions, offsite credits are a valuable tool in achieving net zero, especially for buildings where complete on-site mitigation is challenging.

Journey to Net Zero

The journey to net zero for the City of London's existing buildings is a complex but achievable goal. By adhering to stringent standards, respecting heritage constraints, addressing both operational and embodied carbon, leveraging technological advancements, and utilising offsite credits, the City can lead by example in the global effort to combat climate change. This holistic approach ensures that London's historical and cultural fabric is preserved while paving the way for a sustainable future.