MIMA Statement on the NAO’s Energy Efficiency Installations Report
High-quality, well-installed insulation remains one of the most effective measures for reducing household energy bills, cutting carbon emissions, and improving thermal comfort in our homes. However, the National Audit Office’s Energy Efficiency Installations report[1] highlights serious shortcomings in the oversight and quality assurance of flagship government retrofit programmes created to deliver home insulation and other measures.
Poor-quality installations harm consumers, damage businesses, and undermine confidence in the entire retrofit sector, and we support the NAO in its call for robust action to address the failings identified, for those directly affected and for consumers more generally.
Statistics quoted in the NAO’s report make clear that other government retrofit schemes have not suffered from the same systemic failings, suggesting that the problems revealed stem from specific, yet deeply ingrained issues with the design, implementation, and delivery of the schemes in question – rather than the external or internal wall insulation itself. The findings reinforce the urgent need for robust end-to-end, outcomes-focused quality assurance requirements to stop similar issues arising in future schemes and to protect consumers.
For households in fuel poverty or those "just about managing", well-installed insulation remains the foundation of affordable warmth. A high-quality insulation lowers the amount of energy needed for heating, creates healthier homes, and maximises the benefits of clean heating systems such as heat pumps. Poorly installed, and un-checked or un-monitored measures risk leaving vulnerable households living in poor conditions and worse off, undermining public confidence.
MIMA’s report Making Performance-Led Home Retrofit a Reality[2] sets out clear solutions. Outcomes-based guarantees of performance, underpinned by robust measuring, metering, and monitoring of retrofitted measures, would drive up quality, close performance gaps, protect consumers, and help ensure promised energy savings are delivered in practice.
Such a performance-led approach means any poor-quality installations are identified and addressed - or prevented altogether - before problems arise, improving standards across the sector. Installers who are already offering such checks and verification of their work are likely to be installing to a high standard and should be recognised for doing so. Embedding these principles into retrofit policy and funding frameworks will de-risk the retrofit journey for both consumers and government, ensuring investment delivers long-term value, measurable results, and builds long-term trust in the retrofit market. Consumers truly get high quality installs, with verified energy savings and improved home comfort, matching their expectations.
MIMA, in partnership with the Energy Efficiency Infrastructure Group and the National Retrofit Hub, and working alongside the previous Consumer Energy Minister, Miatta Fahnbulleh MP, had been developing practical solutions towards a framework to tackle quality assurance and prevent further issues. We urge the Government and the new Consumer Energy Minister, Martin McCluskey MP, to pick this work up and secure a performance-led, “measures that deliver” approach in policy - beginning immediately with the long-awaited Pay for Performance in the government’s fuel poverty programme, the Energy Company Obligation and for this approach to be woven into the very fabric of the forthcoming Warm Homes Plan.
For further details, please contact:
Sarah Kostense-Winterton, Executive Director
Email: sarah@mima.info
Tel: 020 7293 0870
[1] https://www.nao.org.uk/wp-content/uploads/2025/10/energy-efficiency-installations.pdf
[2] https://mima.info/media/1253/mima_hpi_paper_0225.pdf