Great British Insulation Scheme (GBIS)

GBIS — the Great British Insulation Scheme, sometimes called ECO Plus when first announced — was introduced in March 2023 to plug a gap in the existing grant landscape. Households just above the ECO4 benefit thresholds were getting nothing, despite often being in homes equally in need of insulation.

The scheme is small relative to ECO4 (£1bn vs £4bn+) and narrower in scope (insulation only, not whole-house). But for the right household it is the most accessible UK home energy grant in 2026.

What GBIS actually is

GBIS is structured similarly to ECO4 — a regulatory obligation on energy suppliers with more than 150,000 customer accounts. The funding pool is £1bn over the scheme's lifetime, split across the obliged suppliers in proportion to their customer share.

The scheme has two eligibility groups:

• General Group — household lives in a property in council tax bands A-D (England), A-E (Scotland), or A-D (Wales), and has a current EPC of D, E, F, or G. No benefit or income test.
• Low Income Group — household receives a means-tested benefit (same list as ECO4). Property condition rules still apply.

The Low Income Group reuses the ECO4 eligibility evidence pipeline and was added to make GBIS administratively simpler — the same managing agents and installers handle both schemes for low-income households.

The General Group is the genuinely new audience. Around 80% of GBIS measures to date have been delivered through this route, often to households who had been told repeatedly they did not qualify for ECO grants because they were not on benefits.

How GBIS differs from ECO4

The "council tax band A-D" rule is the headline test most households apply first. In England this captures roughly 60% of households, broadly matching the lower 60% of property values. Scotland's A-E band threshold is more inclusive (around 75%). Wales is similar to England.

What GBIS will pay for

GBIS funds insulation measures only. The list is narrower than ECO4's because heating, solar, and ventilation are out of scope.

GBIS does not fund glazing, doors, mechanical ventilation, or any heating measures. Heating sits with BUS for low-carbon options and was funded under ECO4 only for whole-house packages.

The one-measure cap and how to think about it

The defining constraint of GBIS is that each household can claim one measure only. This is in deliberate contrast to ECO4's whole-house approach.

The cap means a household chooses the highest-impact single measure. For most homes the priority order is:

1. Cavity wall insulation if cavity is empty or partially filled (and not previously rejected on damp grounds). Highest cost-effectiveness — typical payback 4-6 years.
2. Loft insulation if the loft is below 200mm. Cheap, fast, easy. Payback 3-5 years.
3. Solid wall insulation external if the home is solid-walled and the elevation suits external. Most expensive but biggest single-measure impact on EPC.
4. Underfloor insulation for suspended timber floors with adequate access.
5. Room-in-roof for converted attics — niche but transformational where it applies.

The exception to the one-measure rule: a "combined" loft + cavity package is sometimes treated as a single GBIS claim by managing agents, on the grounds that they are typically installed in one visit. This is a managing-agent-by-managing-agent variation and not a guaranteed rule.

For households who want both loft and cavity insulation, asking specifically about combined claims at quote stage is worth doing — some installers will run them as one ticket; others insist on two separate claims (which under the cap means only one).

How to apply

The application process mirrors ECO4. There is no central portal; applications run through installers and managing agents.

1. Self-check eligibility. Confirm council tax band (on your council tax bill), EPC band (search the EPC register), and any benefit awards.
2. Find an installer. Most ECO4 installers also handle GBIS. TrustMark's directory is the safest starting point. Avoid cold-callers.
3. Survey. The installer surveys for the proposed measure, checks the property is suitable (in particular for cavity work — pre-install damp inspection is mandatory).
4. Application. Installer submits to the managing agent, who confirms eligibility and lodges with the supplier.
5. Approval and install. 2-6 weeks for approval, 1-3 weeks for install in most cases. Solid wall takes longer.
6. Lodgement. Installer lodges with TrustMark and the supplier. EPC update follows within 4-8 weeks.

Common reasons GBIS applications get rejected

The single most common rejection in 2024-25 was the council tax band check. Households often assumed that EPC and income alone would do it, only to find the band E/F/G rule blocking the application. The rule exists to focus the General Group on lower-value housing.

GBIS Plus — what is being designed for 2026-2030

The Department for Energy Security and Net Zero (DESNZ) consulted on the successor scheme in late 2024 and again in early 2026. The provisional name is GBIS Plus, though the final branding is not yet confirmed.

The design direction:

• Combined GBIS and ECO4 elements. One scheme rather than two parallel obligations, reducing the administrative overhead for installers and managing agents.
• Broader insulation scope. The one-measure cap may be relaxed to allow loft + cavity combinations as standard.
• Heating split off to BUS-3. Heat pumps will continue under a successor BUS, not under GBIS Plus.
• Higher per-property cap. Likely £6,000 - £10,000 (versus GBIS's effective £1,000-£11,000 single-measure range).
• Council tax band rule retained. Bands A-D will likely remain the General Group threshold in England.
• Stronger consumer protection. A doorstep selling ban, mandatory cooling-off period, and tighter installer sanctions for mis-selling.
• 4-year scheme term. April 2026 to March 2030.

The practical implication for households: if your home meets GBIS criteria but you are still within the application window (to roughly autumn 2025), apply now under GBIS rather than waiting. The cap is one measure either way, and managing agents close their books before March 2026 to deliver lodgements.

If you are unsure whether to apply now or wait, the calculus tilts towards applying now if the measure is loft, cavity, or underfloor (low cost, fast install, predictable). For solid wall it may be worth waiting to see whether GBIS Plus opens up a fuller package — but only if the home can stand another winter undone.

GBIS is the most under-publicised UK home energy grant — partly because the council tax band rule sounds restrictive, partly because the one-measure cap looks limiting next to ECO4. But for a household in council tax band A-D with EPC D or below, GBIS is often the most reachable single intervention available, with no benefit test and a relatively quick application path.

The window is closing fast. March 2026 is the formal end and managing agents typically stop accepting new files in autumn 2025 to ensure delivery. If your home fits the criteria, this season is the time to check.

For a 60-second check of GBIS, ECO4, BUS and SEG eligibility against your specific property, run the Green Home Grants eligibility checker. If you would prefer to discuss the right measure with an independent retrofit assessor first, the directory at Healthy Homes Network lists qualified PAS 2030 and PAS 2035 assessors by region.