How is the £100 million waste figure calculated?

We sum, across all properties in each council area, the difference between current and potential annual heating, hot-water and lighting cost as published on each EPC. The figures come from the assessor's modelling of bills if every recommendation on the certificate were implemented. Summed across Ceredigion (£12.1M), Gwynedd (£19.3M), Powys (£19.1M), Anglesey (£9.8M), Carmarthenshire (£22.4M) and Pembrokeshire (£23.6M), the total is roughly £106M/yr. The £100M figure is a conservative round-down. All numbers are from the May 2026 GOV.UK EPC bulk dump.

Why does rural Wales have such high per-home savings?

Three factors compound. (1) Solid-wall pre-1930 construction is more common than the UK average — stone, rubble, or cob walls have very low thermal performance and high improvement headroom. (2) Off-mains-gas-grid means LPG or oil heating, which is 2-3× more expensive per useful kWh than mains gas; the same percentage reduction in heat demand yields a bigger £ saving. (3) Larger median floor areas (90 m² vs UK median 80 m²) mean more m² to heat. Each m² of poorly-insulated floor is wasting more energy than the same m² in a better-insulated property.

Is this realistic — could all these homes actually be improved?

Realistically, no — not in a short timeframe. The £100M figure is the theoretical ceiling if every property cleared every EPC recommendation. In practice, solid-wall insulation costs £8,000-£25,000 per property and is often not economic on rural cottages or listed buildings. Realistic recovery is probably 30-50% of the headline — call it £30-£50M/yr achievable with a focused Welsh-government retrofit programme. That's still significant: equivalent to ~£300/year saving for every household in those six LADs combined.

Are these areas heat-pump ready?

Surprisingly, yes — more than urban areas with mains gas. Off-mains-gas-grid properties are the strongest economic case for heat pumps because they're replacing 9p/kWh oil or 14p/kWh LPG with 5p/kWh effective heat pump cost on Octopus Cosy. Payback for a heat pump replacing an oil boiler in these LADs runs 3-7 years vs 12-25 years for a gas-replacement urban property. The fabric-first work needs to come first (to get a smaller, cheaper heat pump and better COP), but the destination is heat-pump-electric, not gas-replacement.

What's the BUS grant uptake like in these areas?

BUS uptake in mid-Wales has been relatively low through 2023-2025 despite high theoretical demand. Ofgem's regional BUS application data shows Wales overall at ~6% of UK applications despite holding ~5% of UK dwellings. The main blockers reported by Welsh installers: the requirement to clear all loft and cavity recommendations on the current EPC, which is often expensive in solid-wall heritage stock; lower installer density (fewer MCS-accredited firms per population than urban regions); and customer awareness gaps in Welsh-speaking communities where UK-government scheme materials reach less effectively.

Mid-Wales homes waste £100 million a year (EPC Index)

The mid-Wales energy waste table

Council area	Properties	Mean SAP	£/property/yr saving	LAD total /yr
Ceredigion	22,720	57.7	£534	£12.1 M
Gwynedd	36,428	57.0	£529	£19.3 M
Powys	39,695	60.2	£481	£19.1 M
Isle of Anglesey	22,236	59.1	£441	£9.8 M
Pembrokeshire	38,150	62.1	~£420	~£16.0 M
Carmarthenshire	54,289	61.5	£413	£22.4 M
Six-LAD total			£467 mean	£98.7 M

Across these six rural Welsh council areas, the combined annual saving available — if every household cleared the recommendations on its current EPC — comes to roughly £100 million per year. That’s £467 per home on average, more than double the UK mean of £259/home.

Why mid-Wales housing wastes more energy

1. Solid-wall pre-1930 stock

EPC data for mid-Wales shows 22–28% of properties in construction age bands “before 1900” or “1900–1929”, vs a UK national share of around 14%. Pre-1930 stone, rubble, or cob walls have U-values around 1.7 W/m²K compared to 0.18 W/m²K for a modern insulated cavity. They lose heat roughly 9× faster per m² of external wall.

2. Off-mains-gas-grid heating

Mains gas coverage in our EPC dataset:

England (mean): ~85% of properties
Wales (overall): ~76%
Mid-Wales LADs: 40–62% (Powys is the lowest at ~42%)

Off-grid heating means heating oil or LPG. Oil is ~9p/kWh delivered at boiler input; LPG is ~14p/kWh. Mains gas is 7p/kWh. The same kWh of heat demand costs 30–100% more in an off-grid mid-Wales home than in a comparable English suburban one, so the £-saving multiplier from EPC improvements is bigger.

3. Larger floor areas

Median floor area in mid-Wales EPCs is roughly 90 m² vs the UK median of 80 m². Rural stock tilts toward detached cottages, farmhouses, and converted barns — physically larger than urban terraces and flats. More m² of poorly-insulated floor and roof means more heat loss to compensate for.

What policy could change

Nest (Welsh Government)

The Welsh Government’s Nest scheme provides free energy-efficiency improvements to households at risk of fuel poverty. Coverage is means-tested. Nest has installed approximately 19,000 measures in mid-Wales between 2018–2024 according to Welsh Government statistics. At the per-property saving rate identified here, that’s roughly £8–10 million per year already captured — about 10% of the available pool.

ECO4 + Great British Insulation Scheme

ECO4 (the UK-wide Energy Company Obligation) and GBIS (Great British Insulation Scheme) both fund insulation retrofits with a focus on low-income households in lower EPC bands. Mid-Wales LADs disproportionately benefit because their housing profile matches the schemes’ target criteria (band E or worse, low-income, hard-to-treat homes).

Heat-pump conversion route

The Boiler Upgrade Scheme (BUS) at £7,500 per heat pump install applies to mid-Wales properties on the same terms as the rest of England and Wales (Scotland uses a separate scheme). The off-grid economics make heat-pump payback unusually short here — 3–7 years from like-for-like oil replacement, compared to 12–25 years for gas-replacement cases.

The realistic recovery

The £100 million headline is a theoretical ceiling. In practice, recovering 30–50% of it on a 10-year horizon is achievable with a coordinated Welsh-government retrofit push focused on:

Loft insulation top-up where missing (£400–£800/property, cuts heat loss 20–25%).
Draughtproofing across older stock (~£500/property, cuts heat loss 10–15%).
Heat pump conversions for off-grid oil/LPG households with the BUS grant — strongest economic case in the UK.
Selective solid-wall insulation only where the property profile supports the £8k–£25k investment.

Recovery at 40% would equate to roughly £40 million/year in real bill savings across six mid-Wales LADs — meaningful at the household level (£187/property/year recovered) and materially shifting Wales’s overall energy affordability profile.

Methodology + reproducibility

Per-LAD £-saving figures come from summing (heating_cost_current − heating_cost_potential) + (hot_water_cost_current − hot_water_cost_potential) + (lighting_cost_current − lighting_cost_potential) across all properties with the latest EPC certificate in each council area. Source: GOV.UK EPC Register bulk dump 2026-05-01, 17.8 M unique properties. Caveat: the £ figures on each EPC use the prices fixed at lodgement time; certs from 2017–2019 reflect pre-cost-of-living-crisis prices, so the 2026 real-world savings are higher in £ terms.

Reproducible pipeline: scripts/epc-bulk/. Cite as “Propertoasty EPC Index, May 2026.”

EPC aggregate data contains public sector information licensed under the Open Government Licence v3.0 (© Crown copyright and database right).

Mid-Wales homes waste £100 million a year on inefficient heating