ECO4 Closes 31 December 2026 · Warm Homes Plan from 2027 | 7,000+ Installations
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💰Earn £100 Per ReferralBy Peter Davies, ECO4 Analyst
Reviewed
Pillar guides: Free boiler upgrade · ECO4 eligibility · LA Flex grants
CF1–CF99
Postcode coverage
Wales & West Utilities
Gas Distribution Network
LA Flex active
Cardiff Council
£0
Cost to qualifying households
There are two routes for Cardiff households. Pick whichever applies — you don't need both.
Per gov.uk's Energy Company Obligation page, you qualify if you receive any of:
No qualifying benefit? Cardiff Council runs its own referral route through the LA Flex Statement of Intent.
Bottom line: If your address is in CF1–CF99, you claim a qualifying benefit or fall under Cardiff Council's LA Flex criteria, and your EPC is D-G, the eligibility check is a 49-second form.
Cardiff has roughly 155,000 dwellings spread across a tight urban core and post-war suburbs. The pre-1919 stock is concentrated in Roath, Cathays, Splott, Grangetown and Riverside — long rows of Welsh red-brick terraces with original Welsh slate roofing, solid-wall construction, and the characteristic two-storey bay-front layout. EPC ratings on this stock cluster in band D-F because of the solid walls and original sash windows. Post-war Cardiff Council estates in Llanrumney, Pentwyn and Llanedeyrn add another large pool of EPC D-E semis. Newer estates in Pontprennau and the Cardiff Bay redevelopment fringe (CF10) sit in band C and rarely qualify. Across the city, the dominant ECO4 candidates are the Roath / Cathays / Splott terraces with ageing non-condensing combis, and the post-war ex-council semis still running on Economy 7 storage heating.
Bottom line: Cardiff's mix of pre-1919 and post-war stock is exactly the catchment ECO4 targets. The mandatory PAS 2035 retrofit assessment will confirm the SAP uplift for your specific address.
Wales & West Utilities is the Gas Distribution Network operator for Wales and the South-West — that includes every CF1–CF99 postcode.
~10 m connection
£500–£800
50 m+ connection
£1,500–£2,500
If your property is already on the gas main — most Cardiff addresses are — there is nothing to pay. ECO4 funds the boiler, internal pipework, controls, meter installation, and safe removal of the old system.
Wales & West Utilities's indicative pricing toolBottom line: Almost every Cardiff address (CF1–CF99) is already on the Wales & West Utilities gas main, so the connection cost is £0. The rare off-main cases sit on the outer fringes and pay Wales & West Utilities separately for the new connection.
Nest is the Welsh Government's flagship Warm Homes scheme (freephone 0808 808 2244) and runs in parallel with ECO4. To qualify for Nest you must own your home or privately rent (council and housing-association tenants are excluded), and either receive a means-tested benefit, live in a low-income household, or have a respiratory, circulatory or mental health condition. Welsh households should run both checks — Nest covers some properties ECO4 does not (and vice versa). Together with the Optimised Retrofit Programme, Welsh schemes deliver over £130 million a year in energy-efficiency upgrades.
NestBottom line: Nest runs in parallel with ECO4 — the eligibility tests are independent, so check both before you decide which to apply for first.
You may have seen the successor scheme called "ECO5" online — there is no ECO5. The government has abolished the Energy Company Obligation model and replaced it with the Warm Homes Plan — a £15 billion programme funded by public investment rather than levies on energy bills. ECO4 still runs until 31 December 2026, so Cardiff households should apply now while the scheme is open.
Low-income grants
£4.4 bn
Warm Homes Social Housing Fund + Local Grant
Boiler Upgrade Scheme
£7,500
per household, clean-heat grant
Delivery moves from Ofgem to a new Warm Homes Agency, with the Social Housing Fund and Local Grant consolidating into a single low-income capital scheme by 2027/28. Welsh households continue to apply through the Nest scheme, with additional Warm Homes Plan funding allocated to Wales via Barnett Consequentials.
Sources: gov.uk — Warm Homes Plan (updated 18 March 2026); Ofgem response to the Warm Homes Plan.
Bottom line: ECO4 closes 31 December 2026. The Warm Homes Plan replaces it from 2027 — apply now while the current scheme is still open and the £4,000–£8,000 install value is fully funded.
Property
Late-Victorian two-storey mid-terrace, two-bed, Welsh slate roof on solid red-brick walls
Existing system
Mid-1990s non-condensing combi vented through the side wall; original sash windows; EPC band E
Measure installed
New A-rated condensing combi sited in the kitchen with a new horizontal flue; existing iron radiator circuit flushed and re-balanced; programmable thermostat and TRVs added throughout. Solid-wall insulation was scoped separately because the household preferred to retain the original brick aesthetic.
Outcome
EPC modelled uplift from band E to band C; annual gas demand reduced by ~25% across the first heating season. Eligibility flowed via Universal Credit; the household also ran a parallel Nest application but chose the ECO4 route because the install timeline was faster.
Time on site
One day on site for the boiler swap; flue-route survey the week before.
Illustrative — based on typical CF1–CF99 installs, not a single named customer.
Bottom line: Typical Cardiff installs deliver a two-band EPC uplift in a single intervention at £0 to the qualifying household. Your individual case depends on the PAS 2035 assessment, but the CF24 Roath pattern above is representative.
Total install value typically £4,000–£8,000.
Most Cardiff addresses are already on the gas main — nothing extra to pay.
Bottom line: If your ECO4 application is approved, the install is £0 — typical install value £4,000–£8,000. The only out-of-pocket case is a brand-new gas-main connection from off-grid, which is uncommon in Cardiff.
Run our wizard or call +44 7375 868046.
A free home survey by an accredited assessor confirms the right measure for your property.
Gas Safe install, building-control sign-off, lodged on the TrustMark Data Warehouse.
Prefer to contact Cardiff Council directly?
Installer chain verified via TrustMark and Ofgem ECO4 Delivery Guidance v4.0.
Bottom line: From the 49-second eligibility check to a commissioned boiler, a typical Cardiff ECO4 job runs five to seven weeks. The wizard above is the fastest start — or call +44 7375 868046.
Cardiff Council has partnered with EON to deliver ECO4 LA Flex. Applications go through EON rather than the council energy team — call 0333 202 4422 or apply through us. The council's Statement of Intent sets out the flexible eligibility criteria, which include NICE cold-home vulnerability indicators (cardiovascular, respiratory, mental-health conditions) alongside the standard low-income proxies. Cardiff Council still confirms the declaration, but the customer-facing delivery is EON's.
Nest is the Welsh Government's flagship Warm Homes programme (freephone 0808 808 2244) and runs in parallel with ECO4 — it does not replace it. To qualify for Nest you must own or privately rent (council and housing-association tenants are excluded), and either receive a means-tested benefit, live in a low-income household, or have a respiratory, circulatory or mental-health condition. A Cardiff household can be eligible for ECO4, for Nest, for both, or for neither. The pragmatic order is normally an ECO4 check first because the boiler-replacement uplift is faster; Nest is the fallback for households outside ECO4's benefit gate.
Wales & West Utilities (WWU) is the GDN for all CF postcodes. ECO4 covers the new boiler, internal pipework, the meter installation and the safe removal of the old system at no cost. The connection from your meter to the WWU main is separate — WWU's published 2025 standard charges are £769 + VAT (public-land work only), £856 + VAT (you dig your trench), or £1,443 + VAT (WWU dig the trench), with the standard scope covering up to 10 metres of public land and 20 metres on your land. WWU's Warm Home Assistance Scheme can fund some of this for households aged 70+ or on qualifying benefits.
Yes. The vast majority of Cardiff's pre-1919 terraces in CF24 (Roath, Cathays, Splott, Adamsdown) and CF11 (Grangetown, Riverside) qualify because the solid-wall construction puts EPC ratings in band D-F, which is exactly the ECO4 catchment. Flue routing in a terrace with original sash windows takes a half-day longer than a modern build because the flue must terminate clear of openable windows, but it is standard work. Solid-wall insulation is a separate retrofit measure under ECO4 and is usually scoped only when the homeowner agrees — many Roath homeowners decline because they want to retain the original red-brick aesthetic.
The Energy Company Obligation is a UK-wide scheme funded by energy suppliers and overseen by Ofgem, so the core ECO4 benefit-route eligibility is identical in Cardiff and Liverpool. The differences in Wales are: (1) Wales has its own devolved Warm Homes programme — Nest — which Welsh households should check alongside ECO4; (2) the GDN is Wales & West Utilities, not Cadent; (3) local authority delivery in Wales often goes via energy-supplier partners (Cardiff Council uses EON) rather than in-house council teams; and (4) the forthcoming UK Warm Homes Plan funding will be allocated to Welsh Government via Barnett Consequentials, with Welsh Government deciding how to deploy it.
A Cardiff landlord can decline the application, but they cannot evict you or raise the rent for asking. Private rental properties qualify at EPC band E-G (rather than D-G for owner-occupiers) and the upgrade is a no-cost asset improvement for them. From April 2025 the proposed Minimum Energy Efficiency Standards uplift toward EPC band C is the regulatory backdrop most Cardiff landlords use to justify saying yes. Welsh tenants who hit a wall with their landlord should also check Nest, which can sometimes support landlord-consented work the landlord otherwise resists.
ECO4 closes 31 December 2026. After that, the £15 billion Warm Homes Plan takes over from April 2027 — funded by public investment rather than energy-bill levies, and delivered by the new Warm Homes Agency rather than Ofgem (gov.uk Warm Homes Plan, updated 18 March 2026). You may have seen the successor scheme called 'ECO5' online — that name is not used by government and no scheme by that title exists. For Cardiff households, the practical effect is straightforward: if you apply under ECO4 before the 31 December 2026 close, the install is funded under ECO4 even if the engineer's visit happens in early 2027; if you start a fresh application after 1 January 2027, you'll be routed through the Warm Homes Local Grant (WHLG), the Warm Homes Social Housing Fund, or the £7,500 Boiler Upgrade Scheme depending on your tenure and property. Your local council's energy team continues to handle the referral throughout the transition.
gov.uk — Energy Company Obligation (ECO4)
Qualifying benefits and EPC band rules
Ofgem — ECO4 Delivery Guidance v4.0 (March 2026)
Scheme closure 31 December 2026, measure rules
gov.uk — Warm Homes Plan
£15bn ECO4 successor scheme, updated 18 March 2026
Cardiff Council — Energy Company Obligations (ECO4) page
last updated 2023-09-01
Cardiff Council — ECO Flexible Eligibility Statement of Intent
LA Flex thresholds and vulnerability criteria
Wales & West Utilities — new gas connection page
GDN-side connection-cost guidance
Welsh Government — Energy Performance Certificates statistics
Regional EPC band distribution
Page reviewed: .
49-second form. No commitment. No cost. CF1–CF99 households on Universal Credit, Pension Credit, PIP, ESA, JSA, Income Support, Housing Benefit or Child Benefit — start here. Apply under ECO4 now (closes 31 December 2026); the Warm Homes Plan (sometimes searched as "ECO5") replaces it from April 2027.
