When heritage rules out the usual fixes, ingenuity delivers a low-carbon Westminster hotel
Whitecode Consulting paired technical expertise with creative problem-solving to make a listed Westminster building work as a low-carbon hotel. Where heritage restrictions ruled out the usual fixes, bespoke modelling and a full sustainability scope, from energy strategy to whole life carbon, kept Nobel House on a credible path to lower-carbon operation.
Nobel House occupies a prominent position at Smith Square, London SW1P, and spans 20,325m2 across eight storeys and a basement. The project involves the refurbishment and change of use of the existing building into a heritage hotel, a project type that demands careful balance between modern operational requirements and the preservation of the building's historic character. The scheme is being developed by Criterion Capital, with FBM Architects leading the architectural design.
Appointed to deliver Stage 3 sustainability services, the team’s scope included an energy strategy, SBEM modelling, overheating assessment, Dynamic Simulation Modelling (DSM), and solar shading analysis, as well as a BREEAM pre-assessment, Circular Economy Report and Whole Life Carbon Assessment.
The building's listed status defined the boundaries of the project from the outset. Heritage sensitivities placed significant restrictions on external alterations to improve fabric performance, opportunities for façade upgrades, and the placement of new plant and low-carbon technologies. This meant the conventional toolkit for improving building performance was largely off the table, requiring a more creative and constraint-aware approach.
Working alongside FBM Architects and the MEP engineers, the team used detailed modelling to evaluate realistic performance outcomes within these existing constraints, helping the design team balance operational efficiency with protected-building limitations.
On the mechanical systems side, Variable Refrigerant Flow (VRF) systems were identified as the most appropriate solution: capable of providing both heating and cooling to meet guest comfort expectations, while requiring less invasive pipework distribution around the building.
The slimline emitters associated with VRF systems can also be more easily concealed behind decorative panelling, keeping the building's historic interior appearance intact.
The project involved 'cocoon' guest rooms - windowless accommodation spaces that required dedicated performance evaluation. Bespoke 'shoebox' models were developed to quantify the heating load, cooling demand, artificial lighting energy consumption, and overall effect on building energy intensity of these atypical room types, ensuring their inclusion in the scheme did not compromise overall energy compliance.
DSM was used to assess overheating risk across a range of hotel room types, accounting for the constraints of the retained heritage façade and the limited scope for external design changes. The modelling was also used to quantify carbon emissions and assess compliance with Westminster City Council's energy and carbon policies, providing the evidence base needed to support the planning application.
On low-carbon heating, the team engaged directly with the local District Heating Network operator to explore the potential for future network connection as part of a long-term decarbonisation pathway. Following detailed discussions and cost appraisals, it was agreed with the client that a future connection point would be provided to serve the building's domestic hot water (DHW) demand only, rather than space heating, recognising that DHW represents the largest share of energy consumption in hotel use and therefore the area of greatest potential carbon saving.
Solar shading analysis was also carried out to identify roof areas suitable for photovoltaic (PV) solar installation, accounting for overshadowing, building geometry, and the heritage constraints affecting panel placement and visual impact.
Beyond energy, a BREEAM pre-assessment showed the building could achieve an Excellent rating under the BREEAM Refurbishment and Fit Out scheme.
The Whole Life Carbon Assessment, required by Westminster City Council, set out to show that a major retrofit of a city-centre building could deliver far lower embodied carbon than demolition and redevelopment. By retaining and repurposing the existing structure, the project avoided approximately 3,000 tonnes of embodied carbon, achieving an upfront carbon intensity of just 160kgCO2e/m2.
The Circular Economy Report set out a retrofit-first design focused on longevity and future adaptability. The project is expected to divert approximately 98% of demolition waste from landfill, while preserving the architectural and heritage value of a significant Westminster landmark.
Ben Talbutt, Senior Sustainability Engineer at Whitecode Consulting said: "Nobel House presented a genuinely complex sustainability challenge. The listed status of the building ruled out many of the interventions we might typically reach for, so it was about using detailed modelling intelligently to understand what was achievable within the constraints, identify where the biggest gains could be made, and give the design team the evidence they needed to make well-informed decisions.
"Working closely with the architects and MEP engineers, we were able to develop a strategy that respects the heritage context while still setting the building on a credible path toward lower carbon operation as a hotel."
