Government cracks down on rogue retrofit contractors

Nearly 300,000 UK homes had insulation installed under the Great British Insulation Scheme last year, but an unknown number of those upgrades will never deliver a penny of savings. Poor workmanship, from badly fitted loft rolls to cavity wall gaps, has become a systemic drain on household budgets and public trust in the entire retrofit programme.

The UK government has now announced a targeted crackdown on rogue retrofit contractors, as reported by Construction Digital. The move follows a National Audit Office report in 2023 that found up to £1.5 billion of public money had been spent on energy efficiency schemes with no measurable impact, much of it lost to substandard installations.

Who qualifies, and who doesn’t

The new enforcement targets contractors who are not registered with recognised accreditation bodies such as MCS (Microgeneration Certification Scheme) or TrustMark. These are the only routes to government-funded schemes like the Boiler Upgrade Scheme (£7,500 grant for heat pumps) or the Great British Insulation Scheme (free or subsidised loft and cavity wall insulation). If your installer is not on either register, you cannot claim the grant, and you may be left with an upgrade that fails within months.

Ofgem, which administers the schemes, has begun auditing a sample of completed installations. Homes where the work does not meet standards will face clawback of the grant, meaning the contractor, not the homeowner, must repay. But in practice, many rogue firms simply dissolve and reappear under a new name. The government’s answer is a central database of banned contractors, shared across all schemes, to make serial non-compliance harder to hide.

What it costs a typical 3-bed semi

A typical 3-bed semi with gas heating and single glazing spends about £1,900 a year on energy, according to Ofgem’s typical domestic consumption values. Proper retrofit, cavity wall insulation, loft insulation to 270mm, double glazing, and an air-source heat pump, can cut that to £900, saving £1,000 annually. But if the insulation is poorly fitted, with gaps that let heat escape, the saving might be just £200–300. Over a decade, that’s £7,000–8,000 of lost savings for a household that paid £10,000–15,000 for the work.

The catch is that homeowners often cannot tell good work from bad until the first winter bill arrives. Cavity wall insulation that slumps inside the wall cavity is invisible until thermal imaging reveals the cold spots. Loft insulation left with compression around pipes can reduce its U-value by half. The government’s new enforcement includes a requirement for all grant-funded installations to include a photographic record of each stage, which homeowners can request.

What this means for your EPC rating

Your Energy Performance Certificate (EPC) rating is the single most influential number on your property’s value and your eligibility for future green mortgages or equity release. A typical D-rated semi can reach a C or B with proper insulation and heating upgrades. But a rogue installation that fails to meet the Standard Assessment Procedure (SAP) methodology will not improve your EPC score, and may even downgrade it if the assessor flags the work as non-compliant.

Energy Saving Trust recommends that homeowners ask for a copy of the installer’s MCS certificate or TrustMark registration number before any work begins. You can verify both online. For heat pumps, the installer must also provide a design calculation showing the system matches your home’s heat loss, a document many rogue contractors skip entirely.

What to do next

If you are planning a retrofit this year, start at gov.uk/simple-energy-advice. The site lists only TrustMark-registered firms. For heat pumps, use the MCS search tool. Do not accept a contractor who cannot provide both a written quote and a stage-by-stage photographic record. And if you suspect poor work on a completed installation, report it to Citizens Advice or the Insulation Ombudsman Scheme, the government has promised faster resolution times under the new crackdown.

Households on standard variable tariffs can apply for the Boiler Upgrade Scheme through their installer from 1 April 2025. Eligibility closes on 31 March 2027. The Great British Insulation Scheme runs until 2026 but may be extended. Neither scheme will pay for remediation of botched work, that cost falls on the contractor, or on you if they vanish. Choose wisely.