It is not clear the future retrofit market will be big enough to sustain businesses to meet the level of remediation required. Since we took evidence in November 2025, the government announced that it would end ECO, with no levies on bills from April 2026. It said it would continue investing to tackle fuel poverty through its Warm Homes Plan but did not provide any further detail.53 In written evidence provided to us after our oral session, the Department clarified that it was yet to formally confirm 49 Qq 64, 66, 67, 147 50 Letter from the Department of Energy Security & Net Zero, dated 2 December 2025 51 C&AG’s Report, para 2.19; Energy Security and Net Zero Committee Oral evidence: Retrofitting homes for net zero, HC 453, 12 February 2025 52 Q 76, 78, 82, 83 53 HM Treasury, Budget 2025, 26 November 2025 16 whether it would extend the period for suppliers to meet their existing ECO4 obligations beyond March 2026. However, there would be no additional obligation beyond the existing ECO4 and GBIS targets.54 The National Audit Office report shows that ECO is by far the largest retrofit scheme, with over 300,000 homes retrofitted via ECO4 and GBIS by the end of March 2025.55 54 Letter from the United Kingdom Accreditation Service, dated 27 November 2025 55 C&AG’s Report, Figure 8 17 2 Reasons for the failures Poor information and oversight