Over the last 18 months, the retrofit sector — particularly schemes like ECO4 and the Great British Insulation Scheme (GBIS) — became a political hot potato. A damning National Audit Office (NAO) report in late 2025 highlighted systemic failures:
- 98% of external wall insulation installed under these schemes had major issues requiring repairs or replacement (e.g., poor sealing leading to damp, mould, or delamination).
- Around 36,000 homes affected overall, with some posing immediate health/safety risks (like blocked vents or exposed wiring).
- Fraud estimates: Installers falsified claims in thousands of cases, costing £56m–£165m.
- Weak oversight meant problems weren’t flagged until media stories about mouldy homes surfaced in 2024-2025.
These scandals damaged public trust, led to calls for reforms (including a new Retrofit System Reform Panel), and contributed to the schemes winding down. Both ECO4 and GBIS officially end on 31 March 2026.
Despite this, rather than the quality of the insulation materials used, the problems largely stem from shoddy workmanship and lax quality controls, not from the insulation measures themselves.
EWI Is a proven energy saving technology!
If you look at EWI as a solution, it can provide a huge number of benefits:
- Significant energy savings — Reduces heat loss through walls (up to 35–45% in solid-wall homes), cutting heating bills by £300–£700+ annually (depending on property size, e.g., £450+ for a detached house). With UK energy prices still high, payback often occurs in 10–15 years.
- Improved thermal comfort — Eliminates cold spots, reduces draughts, and maintains stable indoor temperatures year-round.
- Increase the EPC Rating — Upgrades your EPC rating (often by 1+ bands), making homes more attractive to buyers — energy-efficient properties can sell faster and at a premium (5–14% uplift in some cases).
- Increased ‘Curb appeal’ – The transformation with a freshly rendered property (the typical finish on EWI systems) can truly be remarkable, taking an old property and bringing it back to life.
- Environmental benefits — Lowers carbon emissions (up to 1.5 tonnes CO₂/year) and supports UK net-zero goals.
- Added protection — Shields external walls from weather, prolonging building life.
Make sure to get the EWI Installed by a ‘Carded’ Installer
Obviously, it is key the EWI is installed correctly. We spoke to Paul Christmas, Head of Technical at EWI Pro (a leading UK manufacturer), who made the following comments:
“Yes, correct installation is absolutely critical for External Wall Insulation (EWI) systems — it directly impacts thermal performance, longevity, moisture management, warranty validity, and avoiding issues like damp, cracking, or reduced energy savings.”
He adds on accredited components:
“At EWI Pro, we are deeply committed to delivering systems that homeowners and installers can trust for the long term. Achieving and maintaining BBA certification for our components — including our premium silicone renders like EWI-075 and EWI-076 — is not just a badge; it’s independent proof that our products undergo exhaustive laboratory testing, on-site evaluations, and ongoing surveillance. Using accredited, BBA-certified components significantly reduces the risk of failures, defects, or performance issues, ensuring superior durability, weather resistance, crack prevention, and overall system integrity. In an industry where shortcuts can lead to costly problems, choosing certified materials is essential for safer, more efficient, and longer-lasting external wall insulation installations.”
So while there are lots of materials available on the market, it is definitely worth doing your research before buying any systems and ensuring any installers you use know what they are doing.
Ideally they are ‘carded’ with the system manufacturer, meaning they are proven to be proficient at installing the systems, having gone through training and testing with the product manufacturer. At TheGreenAge, we work with installers up and down the country and can help you find installers for your next project.
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