Sustainability Report
Embodied carbon
The carbon emissions and carbon capture have been calculated using Mesh Embodied Carbon Calculator.
Operational Emissions / Energy
This project employed a comprehensive, fabric-first retrofit approach, resulting in significant reduction in the operational energy, complete removal of on-site fossil fuel and the majority of the energy generated on site.
Roof-mounted photovoltaic panels (PV) integrated with battery storage maximise on-site renewable generation and reduce peak electrical loads. Space heating and domestic hot water are provided by a high-efficiency Air Source Heat Pump (ASHP) designed to operate at low flow temperatures. The pump is largely powered by on-site generated electricity. The retained, previously gas-powered fireplaces converted to bioethanol complete the removal of fossil fuel dependency from site and eliminate direct combustion emissions.
Prior to retrofit, the building relied on gas for space heating, domestic hot water and feature fireplaces, resulting in high operational carbon. During design stage, detailed energy modelling and thermal analysis (PHPP) informed targeted upgrades to the building envelope significantly reducing energy demand of the property.
On-site energy generation, storage and ASHP system meets 68.5% of the house’s operational energy demand. The remaining 31.5% is met by national grid, sourced from Octopus Energy, the provider selected for its reputation of long-term investment in renewable energy infrastructure and operation of own sustainable power system in addition to purchasing electricity from renewable sources.
Envelope upgrades—including wood-fibre insulation, triple-glazing, airtightness, reduced thermal bridging and external sun-shading—work holistically with building services to reduce space heating demand, improve comfort, and mitigate overheating risk.
Innovation lies in the careful integration of contemporary low-carbon technologies within an existing building fabric, balancing performance, architectural quality, and occupant comfort. The all-electric infrastructure supports future grid decarbonisation, ensuring the building remains resilient, flexible, and relevant over time.
Afterlife
Adaptive reuse was considered in the afterlife of the project. The floorplan is designed to be flexible, with multiple pocket doors that allow spaces to be either separated for more private, defined functions or opened up to create larger, continuous areas. This adaptability enables the building to accommodate a range of future programs with minimal structural intervention, supporting long-term usability and resilience.
The project incorporates building elements that support disassembly and reuse. The new extension is constructed using a fully timber frame with wood fibre insulation, both of which are low-impact materials that can be more easily dismantled and reintroduced into the circular economy. Additionally, the roof tiles combine reclaimed and new elements, allowing for potential future reuse while reducing material waste from the outset.
Key products in low carbon design
