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Case Study: Delivering Energy & Sustainability Statement in Westminster

Project Overview
Vision Energy was appointed to develop the energy and sustainability strategy for a London-based residential scheme involving both new-build and refurbishment elements. The design team set out to exceed planning and building regulation targets, with a clear focus on practical carbon reduction and future-proofed energy solutions.

Objectives

  • Achieve on-site carbon reductions aligned with local policy.
  • Maximise building performance through fabric-first principles.
  • Integrate appropriate low-carbon and renewable energy technologies.
  • Ensure flexibility for future energy infrastructure, including district heat networks.

Strategy and Implementation

Vision Energy applied the Greater London Authority’s energy hierarchy Be Lean, Be Clean, Be Green as a framework to reduce energy demand and emissions at every stage. Key design choices were validated through SAP calculations and aligned with local planning requirements.

Energy Efficiency Measures

  • Building fabric upgraded to deliver high thermal performance:
    • Ground floor U-value: 0.13 W/m²K
    • External walls: 0.18 W/m²K
    • Roof: 0.13 W/m²K
    • New glazing: U = 1.2 W/m²K
  • High-efficiency lighting systems (120 lm/W) throughout.
  • Mechanical Ventilation with Heat Recovery (MVHR) installed, delivering 91% efficiency and 0.55 SFP.

Renewable Energy Integration

  • 6.4 kWp roof-mounted Solar PV system paired with a 4kW battery, enabling on-site generation and energy storage.
  • All-electric heating and hot water systems specified to eliminate fossil fuel use.
  • Site designed to be district heat-ready, should a local network become viable.

Environmental Performance Metrics

Performance Indicator Result
Baseline CO₂ emissions 4.09 tCO₂/year
After energy efficiency (‘Be Lean’) 2.99 tCO₂/year
After renewables (‘Be Green’) 2.29 tCO₂/year
Total on-site carbon savings 44%
Annual offset requirement (carbon gap) 2.29 tCO₂
SAP rating (new-build unit) 84 (B)
DER (Dwelling Emission Rate) 12.89 kgCO₂/m²/year
DFEE (Dwelling Fabric Energy Efficiency) 38.42 kWh/m²/year
DPER (Dwelling Primary Energy Rate) 73.91 kWh/m²/year

Broader Sustainability Measures

  • Flood mitigation: Green roof and water butt reduce surface water runoff by 6%.
  • Overheating prevention: Passive ventilation, thermal mass, and orientation strategies used.
  • Materials and embodied carbon: Focus on sustainably sourced and low-carbon materials.
  • Waste and circular economy: Construction waste minimised through reuse and responsible disposal plans.
  • Noise and operational resilience: All technologies assessed for acoustic impact and lifecycle performance.

Outcome

Vision Energy’s comprehensive strategy enabled the development to confidently meet and exceed sustainability goals. The project illustrates how early-stage, data-driven energy planning can be seamlessly embedded in residential development even within dense, constrained urban sites delivering long-term environmental and economic benefits.

Read the whole energy & sustainability statement here;

Energy & Sustainability Statement

 

Sustainability & Building Compliance

Vision Energy are a leading Sustainability & Energy consultancy working nationwide. We specialise in calculations & reports covering Building Regulations, Planning Permission and all other sustainability or energy needs within the construction sector. With a vast amount of knowledge and experience having worked on thousands of projects across the UK one of our engineers would be more than happy to assist you on your project. SAP Calculations | SBEM Calculations | Energy Statements | BREEAM Pre-Assessments | M&E Design | EPC's | Water Efficiency | Air Permeability

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