ECO4 Insulation Quality: High Standards, Rigorous Auditing, and PAS/TrustMark Compliance

ECO4 Standards: Why Auditing Remains Robust and Most Installations Deliver Safe, Warm Homes

Recent headlines from the BBC and other outlets have drawn attention to the troubling experiences of some homeowners whose insulation installations under government schemes led to damp, mould, and serious health concerns. The BBC News article “30,000 homes fitted with botched insulation under government schemes, ministers admit” (September 2025) rightly highlights both the real harm suffered by some families and the Government’s attempts to address these failings.

Below, we explore how UK standards and auditing requirements under ECO4 remain among the highest in the industry, why rogue installers represent a small minority, and how homeowners are protected at every stage through certification, accreditation, and random audits.

The BBC Article: Genuine Concerns, But Not The Full Story

The BBC’s investigation does expose genuine failings. More than 30,000 homes fitted with insulation since 2022 were found, under government audit, to have sub-standard work which may lead to mould or damp. These instances—though by no means trivial—should be understood as a proportion of over 260,000 properties treated under such schemes in the past 15 years.

The article is replete with stories such as Mohammed from Luton, whose father’s health worsened following failed external wall insulation, and Margaret Chappell in County Durham, whose 93-year-old home has been blighted by damp. These cases are tragic, and government ministers have rightly acknowledged “systemic failure” where it has occurred.

Understanding The Scale: A Minority of Unscrupulous Installers

However, it bears repeating: the vast majority of insulation work under ECO4 is professionally executed and provides significant benefits to UK households. The government’s own audit—ordered after media reports and carried out on 60,000 homes insulated since 2022—indicates that roughly half had issues ranging from minor to severe. While this number is concerning, it must be stressed that the installations were the work of a minority of installers who failed to meet standards. See our recent article regarding 39 ECO4 & GBIS installers being suspended.

Most installers operate with integrity, skill, and professionalism. The “systemic failure” the BBC reports is not the result of relaxed regulation, but in our opinion, rather the regrettable actions of a fraction of traders who either cut corners or ignored standards and a lack of oversight from some governing bodies.

Robust Standards: PAS Certification and TrustMark Accreditation

One of the key safeguards built into ECO4 is the requirement for all installers to hold up-to-date PAS certification and TrustMark accreditation. Unlike previous iterations of government support schemes, ECO4 uses two powerful quality assurance frameworks:

PAS 2030 (Publicly Available Specification 2030) is the British Standard for installing energy efficiency measures in existing buildings. It covers everything from wall insulation to heating system upgrades. Every single installer working under ECO4 must comply with PAS 2030:2019, ensuring they follow a strict process for assessment, installation, and post-install sign-off.

TrustMark is the only government-endorsed quality scheme for trades working on homes. To qualify, installers must demonstrate technical competence, customer service excellence, and robust complaints procedures. Inclusion in TrustMark means an installer is subject to random inspections and rigorous vetting.

These requirements are not optional. If an installer is not PAS certified and TrustMark accredited, they simply cannot be registered to carry out ECO4 work. Registration is publicly searchable via TrustMark’s online directory—a useful tool for property owners and landlords.

High Quality Materials and Workmanship Guarantees

Concerns about “botched” installations often centre not just on workmanship but on the materials used. Under ECO4, every measure must be delivered using products certified by UKAS-accredited bodies such as the British Board of Agrément (BBA) or KIWA. These products are subject to testing for longevity, safety, and performance.

Workmanship is further backed by full guarantees, both on the materials and the installation itself. TrustMark requires a minimum two-year workmanship warranty across insulation measures—often the guarantee is longer, depending on the manufacturer and installer. These warranties are legal documents, enforceable through the complaints channels laid out by TrustMark and Ofgem.

Materials are also covered by manufacturer warranties, protecting you against faults and premature failure. In addition, any defects reported by consumers must be rectified at no cost—and most insurance-backed guarantees step in if the original installer ceases trading.

Auditing: Ongoing and Random, Not Just ‘After The Fact’

Contrary to the suggestion that problems are only identified when homeowners complain, auditing is a core part of the ECO4 process:

Random audits: At every stage, installations are subject to random inspections carried out by TrustMark and independent bodies. These audits review everything—from preparatory work and moisture management to finished insulation and compliance with manufacturer instructions.

Targeted audits: Where complaints or issues are raised, Ofgem or TrustMark follow up with targeted audits. Installers found to have breached standards risk losing registration and being struck off, in addition to being held responsible for remediation.

Continuous oversight: Data from completed works is reviewed centrally. If patterns emerge (for example, high failure rates from a particular company), proactive investigations are launched.

The government’s recent audit following BBC reports is evidence of the strong culture of accountability—auditing is both randomised and reactive, and is backed by real consequences.

Redress and Consumer Protection

When things sadly do go wrong, homeowners are not left without support. The government, as stated in minister Miatta Fahnbulleh’s parliamentary report, is “working at speed to ensure substandard installations are identified and remediated at no cost to the consumer”. Those affected should reach out to Ofgem via dedicated emails and Freephone lines.

Homeowners can also contact TrustMark, who have clear processes for complaint escalation and mediation between installers and residents. Crucially, the protections built into ECO4 mean consumers are not expected to pay for remedial work—installers and material suppliers foot the bill.

Building For The Future

ECO4 is part of a decades-long strategy to improve Britain’s housing stock, reduce carbon emissions and fuel poverty, and deliver more comfortable, healthy homes. While the recent audit highlights the importance of ongoing vigilance, standards have never been higher.

Steps You Can Take As A Homeowner

If you are considering ECO4 insulation—or have had measures fitted and wish to check compliance—take the following steps:

Confirm credentials: Use the TrustMark website to search your installer’s accreditation.

Insist on evidence: Request proof of PAS 2030 certification, manufacturer warranties, and the scope of work prior to commencement.

Ask for guarantees: These should be detailed in your contract. Keep them for future reference.

Document everything: Take pictures before, during, and after installation, and retain all paperwork.

Report concerns: If you suspect workmanship is substandard, contact TrustMark or Ofgem as described in the BBC article.

For a more comprehensive view on steps to take please read our recent article here.

In Summary

The BBC investigation shines a necessary spotlight on the importance of high standards for insulation under government schemes. Yet, it is imperative to recognise that problems stem from a minority (albeit a fair sized minority) of unscrupulous or undertrained installers, not from a lack of general regulation. After saying that, it is quite clear that there has been some failings from the governing bodies to audit enough properties to help keep standards high and to punish those that cut corners.

The ECO4 scheme demands PAS certification, TrustMark accreditation, and the use of quality materials with full warranties—all critically supported by random and regular auditing. Where issues do arise, redress is swift, no-cost to the consumer, and comprehensive.

For every distressing story of damp or mould, there are many more families living in safe, warm, energy-efficient homes thanks to robust standards. As the government continues to strengthen consumer protections, British homeowners can be confident that ECO4 remains one of the most tightly regulated and quality-assured retrofit programmes in the world.

If you are affected by these issues or want advice before starting ECO4 work, Ofgem can be contacted by email at ECOhelp@ofgem.gov.uk or by Freephone on 0808 169 4447, Monday to Friday.