The ECO 4 scheme represents the UK's most significant initiative to tackle fuel poverty and upgrade the most inefficient housing stock, specifically those rated EPC D-G. It mandates a holistic, 'fabric-first' approach under the strict quality control of PAS 2035/2030. This means single measures are discouraged; instead, a complete retrofit package (e.g., Solid Wall Insulation, FTCH, and balanced ventilation) is required to maximise energy performance. Smart Energi Hub acts as an accredited delivery partner, managing the complex process: from identifying eligible tenants and securing funding allocation to submitting the final certified completion reports, guaranteeing compliance and unlocking essential capital for decarbonisation projects that deliver genuine, measurable heat savings to residents.