Delivering Next-Generation, nZEB-Compliant Retrofits Through Innovation and Expertise
Project Overview
We successfully delivered a groundbreaking two-stage procurement project aimed at achieving near Zero Energy Building (nZEB) status for existing residential properties—setting a new benchmark in energy-efficient retrofit delivery. Through the strategic use of amended NEC4 contracts, we introduced a bold, performance-focused approach that enabled us to standardise nZEB-compliant designs across all units from the tender stage onward.
Our process was underpinned by conceptual design, innovation and advanced energy modelling during procurement—ensuring precision, predictability, and performance from day one. The retrofit scope included full-fabric upgrades such as External Wall Insulation, high-performance glazing and doors, underfloor, loft and cavity insulation, alongside integrated low-carbon technologies: Solar PV with battery storage, Ground Source Heat Pumps, and Mechanical Ventilation with Heat Recovery (MVHR).
Every detail of the programme was informed by a rigorous Pre-Installation Building Inspection (PIBI), which enabled us to develop a sequenced delivery plan that minimised resident disruption. All works were delivered entirely in-house by our PAS 2030-certified team, with an emphasis on outcome-driven performance guarantees over traditional KPI metrics.
Ahead of the Curve: A Precursor to the GLA Retrofit Accelerator
This project served as a forerunner to the GLA’s Retrofit Accelerator Framework, demonstrating our ability to drive energy savings through a strategic blend of microgeneration, storage, and low-carbon heating solutions. It exemplifies how we turn policy ambition into practical, measurable outcomes.
By applying a consistent design methodology under NEC4 contract principles, we laid the foundation for repeatable, scalable delivery that aligns with both regulatory goals and evolving ESG requirements.
Proven Results: Energy Efficiency That Delivers
Our pilot property achieved outstanding performance:
- Total 10-month energy bill: just £172
- Solar PV output: exceeded design forecasts, even when slightly under MCS-predicted levels
- Resident self-consumption: 13% higher than projected
- Heat pump performance: Delivered exceptional thermal comfort, with bedroom temperatures regularly exceeding standard expectations
These outcomes reinforce the benefits of integrating nZEB building design principles from the outset—ensuring measurable performance and long-term cost savings for residents.
Continuous Improvement Through Data & Insight
Our delivery didn’t stop at installation. We developed a robust platform for real-time data collection, defect analysis, and system optimisation. This enabled:
- Accurate monitoring of energy performance pre- and post-retrofit
- Optimised detailing to eliminate cold bridging risks
- Resident engagement through a structured Aftercare Programme, ensuring users understood and benefitted from new technologies
These insights will continue to inform future nZEB compliance projects across social housing portfolios.
Why It Matters
This retrofit programme demonstrates our strength as a leader in the UK’s retrofit sector, delivering innovative, future-ready solutions that support ESG strategies and meet the ambitious standards of near zero energy buildings.
Our collaborative approach, underpinned by the flexibility of NEC4 contracts, ensures that nZEB buildings are not just compliant, but truly high-performing and scalable for future housing needs.
