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Elevating Energy Efficiency:

The EPC A Rating Achievement of Silbury House


In the dynamic landscape of building sustainability, achieving an Energy Performance Certificate (EPC) A rating is a significant milestone. Silbury House, a structure originally erected in 1998 under the 1995 Building Regulations, has distinguished itself by entering the top 10% of energy-efficient buildings through comprehensive refurbishment efforts that align with the highest modern energy standards.

Silbury House exemplifies the transformative potential of existing office buildings becoming models of sustainability and energy efficiency. 

A Journey of Transformation

The upgrade of Silbury House is an ambitious project, entailing several key interventions that collectively propel the building to its current status of energy efficiency excellence:

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Refurbishment Strategy: 

Central to the transformation was the infill of the atrium, the upgrade of lighting systems to include advanced controls, and the adoption of a hybrid Variable Refrigerant Flow (VRF) system for optimised heating, cooling, and hot water delivery.

Solar Energy Integration: 

A major sustainability feature is the installation of 116 solar panels, with a total capacity of 41 kWp. This system not only covers up to 20% of the building's energy demand but also significantly reduces reliance on non-renewable sources.

Energy and Carbon Management: 

Utilising DesignBuilder software for energy consumption and carbon emissions analysis ensured that refurbishment decisions were both informed and impactful. Measures such as applying solar control film and upgrading blinds contributed to thermal comfort and energy savings.

HVAC and Lighting Upgrades: 

Replacing outdated HVAC systems with energy-efficient alternatives featuring heat recovery technology, alongside installing advanced lighting controls, played a critical role in achieving the EPC A rating. These technologies adhere to the latest Building Regulations, Part L 2021, enhancing overall energy efficiency.

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Architectural and Service Innovations: 

The project navigated the complexities of modernising an older building to meet contemporary standards, incorporating architectural modifications, building services upgrades, and energy-efficient technologies.

Comprehensive Sustainability: 

The integration of extensive solar panels, innovative construction methods, advanced energy systems, and sustainable materials has established Silbury House as a leader in energy performance. Exceptional insulation and minimised energy loss, in line with LETI u-values, underscore its efficiency.

Investment Justification: 

Although the initial investment has been considerable, the long-term energy savings, reduced environmental footprint, and occupant well-being and productivity benefits affirm the project's sustainability credentials.


Silbury House exemplifies the transformative potential of existing office buildings becoming models of sustainability and energy efficiency. The holistic approach taken to secure an EPC A rating demonstrates the comprehensive strategies required to achieve the highest energy efficiency and sustainability standards in office refurbishments. Silbury House now stands as a testament to the feasibility and benefits of retrofitting older buildings for future-ready performance.

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