Insulation Scams, Cold Calls and Mis-Selling

Insulation mis-selling in the UK follows a small number of recognisable patterns, and they all depend on the same thing: a household that cannot easily tell a funded scheme from a sales operation. The warning signs are documented. Citizens Advice describes cold calls trying to sell insulation you do not want or need, claims that insulation must be replaced urgently, and claims of compensation for badly installed insulation¹. It also states the counter-fact that matters most: "Most insulation works properly and you don't need to replace it."¹

The financial damage is concentrated in spray foam. Independent guidance lists a high cost compared to other forms of insulation, reduced ventilation causing condensation and dampness, covering up roof problems, difficulty of removal, lower property value and mortgage difficulty with some lenders¹. Removal is quoted at around £40 per square metre². There are also reports of traders incorrectly installing spray foam insulation and then charging for it to be removed¹.

The protection that exists is procedural rather than automatic. Installers delivering measures under the Great British Insulation Scheme had to be TrustMark-registered businesses³, and the scheme's own guidance states that Ofgem does not administer appropriate guarantees or financial protection for measures installed under it³. That single sentence explains why the paperwork matters more than the sales pitch.

How insulation grant scams work

The mechanism is a cold approach followed by a claim that creates urgency, then a signature. Citizens Advice sets out the three recurring forms: cold calls trying to sell insulation you do not want or need, claims that insulation must be replaced urgently, and claims of compensation for badly installed insulation¹. Each works on a different fear. The first sells an upgrade nobody asked for. The second tells a household that existing, functioning insulation is a hazard. The third offers money back for work that was done badly, which is a particularly effective hook because it sounds like redress rather than a sale.

The "illegal insulation" line is the sharpest version of the second. It is false as a general proposition. Most insulation works properly and does not need replacing, and where there is a genuine problem it is usually obvious, for example severe damp¹. A household told that its loft or cavity insulation is illegal, banned or non-compliant should treat that as a claim to be verified independently, not acted on.

Pressure to sign is the constant. The funded-scheme landscape gives the pressure a plausible frame, because real schemes have existed with real deadlines. The Great British Insulation Scheme ran from April 2023 and installations had to be complete by 31 March 2026, when the scheme ended⁶. A deadline is therefore not itself a red flag; a deadline attached to an unsolicited call, with no verifiable scheme name, administrator or registration number, is.

The independence question is the one to hold on to. A household that takes a cold call has no way to compare the offer, no survey of its own, and no relationship with the installer beyond the call. The scheme rules that governed legitimate delivery were specific about who could install and to what standard, and those rules are checkable after the fact even now that the scheme has closed.

The red flags that mark a mis-selling operation

Red flags cluster around three things: how the contact began, what is claimed about existing insulation, and what paperwork is offered before work starts.

• Unsolicited contact selling insulation. Cold calls trying to sell insulation you do not want or need are named directly as a warning sign¹.
• An urgency claim about existing insulation. Claims that insulation must be replaced urgently, when most insulation works properly and does not need replacing¹.
• A compensation offer. Claims of compensation for badly installed insulation, which invert the direction of a genuine complaint¹.
• No verifiable registration. Installers under the Great British Insulation Scheme had to be TrustMark-accredited and to hold a registration number⁶.
• No pre-work survey or product certificate. Independent guidance expects a pre-work survey report and a product certificate showing what type of spray foam was used¹.
• No guarantee from both trader and manufacturer. Both are listed among the documents a household should hold¹.

The quality problem is not hypothetical. Poor quality workmanship by companies installing solid wall insulation was identified as an issue under the Great British Insulation Scheme⁷, and routine checks carried out by TrustMark, the independent body which oversees tradespeople working in homes, uncovered substandard solid wall insulation⁸. Ofgem wrote to 65,000 households potentially affected by poor-quality solid wall insulation fitted under ECO and GBIS since 2022⁸. As of November 2025, 22 installers had been fully reinstated after meeting requirements on TrustMark's "robust six-point plan", including full remediation of the problems identified⁹.

Spray foam: the insulation most often mis-sold

Spray foam insulation is a type of insulation which can be sprayed on the inside of roofs, in walls and floors¹. It comes in two forms, open cell and closed cell². It was one of the measures covered by the government's Green Homes Grant scheme². None of that makes it illegal, and the question of legality is a distraction from the real issue, which is reversibility.

The risks listed by independent guidance are cumulative rather than theoretical: a high cost compared to other forms of insulation, reduced ventilation causing condensation and dampness, covering up roof problems, difficulty of removal, lower property value, and mortgage difficulty with some lenders¹. Each of these interacts with the others. Foam that covers roof timbers hides defects until they are advanced. Reduced ventilation raises moisture levels in a roof space that was previously breathing. Removal to investigate or repair is expensive, and the cost lands on the household.

Official modelling has examined the moisture question directly. For sprayed foam applied to high resistance underlay, the modelling identified higher levels of risk in some scenarios¹⁰. That is a conditional finding, not a blanket prohibition, and it points to the installation detail rather than the product category as the deciding factor.

The mis-selling pattern specific to spray foam is the removal charge. There are reports of some traders incorrectly installing spray foam insulation, then charging for it to be removed¹. In that sequence the household pays twice: once for work that should not have been done, and again to undo it. The paperwork that would have exposed the problem before installation is a pre-work survey report, a product certificate showing what type of spray foam was used, a guarantee from the trader and a guarantee from the manufacturer¹.

What a genuine grant scheme looked like

The Great British Insulation Scheme, formerly known as ECO+, was a government energy-efficiency scheme administered by Ofgem and covering Great Britain¹¹. It was designed to deliver improvements to the least energy-efficient homes in Great Britain to help tackle fuel poverty and reduce carbon emissions¹¹, and it was expected to cost £1 billion, targeting around 300,000 households⁴. It worked by placing an obligation on medium and large energy companies to deliver measures that result in reduced energy usage¹¹.

The delivery rules are the useful part for anyone assessing a current offer, because they show what a real scheme required. All installers had to be a TrustMark-registered business³, and all measures available under the scheme had to be delivered according to PAS2030/2035 standards³. The scheme delivered the rapid installation of value-for-money insulation measures and, in some cases, heating controls³, with one insulation measure per home⁶. Cavity wall insulation, including party wall, was funded for both eligible groups, and certain heating controls such as room thermostats were allowed as a secondary measure for eligible insulation measures installed in owner-occupied premises in the low-income group³. Higher-cost measures such as solid wall insulation were more likely to require a contribution from the household³.

Eligibility ran through two routes. The general group covered households with properties rated EPC D to G within Council Tax bands A to D in England and A to E in Scotland and Wales⁶. The low-income group covered homeowners or tenants receiving at least one of a listed set of benefits including Child Benefit, Pension Guarantee Credit, Income-related Employment and Support Allowance, Income-based Jobseeker's Allowance, Income Support, Universal Credit, Housing Benefit and Pension Credit Savings Credit⁶. The scheme applied to England, Scotland and Wales¹².

The scheme has closed. The service to check eligibility for free or cheaper home insulation has closed⁵, and applications for the Great British Insulation Scheme have closed¹³. Installations had to be complete by 31 March 2026, when the scheme ended⁶. Any approach now that presents itself as a live Great British Insulation Scheme offer is describing a scheme that has finished.

TrustMark registration: the check that separates legitimate work

TrustMark is the government-endorsed competent person register for finding an installer that will assess your circumstances and property to identify suitable measures¹⁴. Under the Great British Insulation Scheme, all installers had to be TrustMark-accredited and to have a registration number⁶. The requirement was not advisory. The scheme's supply chain guidance states that all installers must be a TrustMark-registered business³.

The register has a second function beyond vetting at the point of hire. TrustMark carried out routine checks that uncovered substandard solid wall insulation⁸, and installers were reinstated only after meeting requirements on TrustMark's "robust six-point plan", including full remediation of the problems identified, with 22 fully reinstated as of November 2025⁹. That is a body with enforcement teeth, not just a directory.

The register's own record-keeping has been criticised. Neither TrustMark nor DESNZ have been able to provide minutes of meetings which took place between 2022 and 2024⁹. That is a governance finding about oversight, and it sits alongside the fact that the checks themselves found real defects.

Registration also appears in legislation beyond the insulation schemes. The Warm Home Discount (England and Wales) Regulations 2026 require that the boiler or central heating system is installed by, or under the responsibility of, a person who is registered with TrustMark, with a certificate of lodgement issued by the operator of TrustMark¹⁵. The same pattern appears in delivery guidance, which states that measures should be installed by or under the responsibility of a TrustMark registered installer and have a relevant certificate of lodgement¹⁶.

For a household, the practical check is narrow: a registration number that can be verified, and a certificate of lodgement after the work. A trader who cannot produce either is not operating to the standard the funded schemes required.

Guarantees, warranties and what protection covers

The guarantee position under the Great British Insulation Scheme is stated without ambiguity: Ofgem does not administer appropriate guarantees or financial protection for measures installed on the scheme³. The current list of appropriate guarantees can be found on the TrustMark website³. That means the household's protection is a contract with an installer and a manufacturer, not a scheme backstop.

Where scheme rules did specify a guarantee, they specified a long one. Under the Northern Ireland Affordable Warmth Scheme, if a household is awarded grant aid for cavity wall or solid wall insulation, the installer employed must be able to provide a minimum 25-year guarantee for the work¹⁷. That is a scheme-specific requirement and it shows the order of magnitude a household should expect for wall insulation.

For spray foam, the documents to hold are a pre-work survey report, a product certificate showing what type of spray foam was used, a guarantee from the trader and a guarantee from the manufacturer¹. Two guarantees, from two parties, is the standard. A single trader guarantee leaves the household exposed if the business ceases trading.

The distinction between a guarantee and a warranty matters here. A guarantee is a promise from a party, enforceable against that party. A warranty is a term of a contract. Neither is insurance, and neither survives the failure of the company that gave it. The scheme's own evidence forms, the Great British Insulation Scheme and ECO4 forms, are used to collect and provide evidence of measure eligibility³, which is why retaining them matters if a problem emerges later.

If the work is already done: surveys, removal and selling

Removal of spray foam is quoted at around £40 per square metre². Independent guidance advises checking with a building surveyor before paying to have spray foam insulation removed, or using a specialist spray foam assessor from the Property Care Association¹. The reasons removal becomes necessary are listed as damp and condensation, damage to the property, or needing to make a repair such as a roof repair¹.

The mortgage question has an official answer that is more permissive than the market sometimes suggests. Where spray foam insulation has been installed in line with the relevant standards, it should not require removal or prevent homeowners obtaining a mortgage². The qualification is doing the work in that sentence: installation to standard, evidenced, is the position the government describes. Independent guidance nonetheless lists mortgage difficulty with some lenders and lower property value among the risks¹, so the practical position depends on the lender and on what the installation looks like.

For a household selling a home with spray foam, the useful preparation is documentary. A pre-work survey report, a product certificate showing the type of spray foam used, and guarantees from both trader and manufacturer¹ answer the questions a lender's valuer is likely to raise. Where those documents do not exist, a specialist assessor's report is the alternative route.

The cost asymmetry is the point to hold. Removal at around £40 per square metre² is a bill that arrives after the original installation cost, and it is the reason the pre-installation advice is to get independent advice from a buildings surveyor before installation, or at least three quotes from different home improvement traders if surveyor advice costs too much¹.

Where to report a scam or complain

Reporting routes differ by what went wrong and under which scheme the work was funded.

• Suspected fraud under the Great British Insulation Scheme: Ofgem's counter fraud section, which also covers Ofgem's role in preventing fraud¹⁸.
• Complaints about an installer: Ofgem or the energy provider¹³.
• Insulation installed under the scheme and faulty: the Ofgem energy company obligation complaints guidance⁵.
• General consumer problems with an insulation sale: Citizens Advice¹.
• Scheme helpline (while it ran): 0800 098 7950¹³.
• Contact details for obligated suppliers: published on Ofgem's linked page¹⁸.

The distinction between fraud and a complaint is worth keeping. Fraud reporting goes to Ofgem's counter fraud function¹⁸. A dispute about workmanship goes through the energy company obligation complaints guidance⁵ or to the installer and the energy provider¹³. A household that has been cold-called but has not signed anything has a consumer problem rather than a scheme complaint, and Citizens Advice is the route for that¹.

For anyone assessing a current approach, the checkable facts are the scheme name and its status, the installer's TrustMark registration number, and the paperwork offered before work begins. The Great British Insulation Scheme has closed¹³, its eligibility checker has closed⁵, and installations had to be complete by 31 March 2026⁶. An offer that cannot be matched to a live scheme, a verifiable registration and a documented guarantee is an offer with nothing behind it.