Wales' Housing Stock and EPC Ratings

Wales has the oldest housing stock in the UK, with 26% of it built before 1919, and the private rented sector is older still, at 43% pre-1919¹. That age profile is the single biggest reason Welsh homes sit at the bottom of the British energy performance table. The Welsh Government's own assessment is blunt: Wales has the oldest and least thermally efficient housing in the UK and Europe².

The measured position is that the average Welsh dwelling scores SAP61 on the RdSAP scale, which is the bottom of EPC band D³. Homes in Wales had a median EPC score of 68, band D, according to records from the ten years up to March 2025⁴. Newer homes are a different story: new dwellings in Wales had a median EPC score of 84 over the five-year period to March 2025, up from 81 in the five-year period to March 2013⁴.

For a household, the practical meaning is that the fabric of the building, not the fuel or the tariff, is usually the binding constraint on both bills and comfort. This page sets out what the Welsh stock looks like, how far EPC data actually reaches, what the Warm Homes Programme has done, and what the carbon budgets now require of Welsh homes.

Wales' housing stock in brief: the oldest in Britain and the hardest to heat

The age of the Welsh stock is not a marginal factor. Wales has the oldest housing stock in the UK, with 26% of this stock pre1919¹. The private rented sector has the oldest stock and highest proportion of poor quality housing, with 43% of stock pre1919¹. Just 6% of Welsh housing was built in the last 30 years, against that deep pre-war base³.

Age translates directly into thermal performance. Pre-1919 dwellings average EPC E (SAP53), and only dwellings constructed post 2000 achieve EPC band C on average (SAP73)³. The average energy efficiency for dwellings in Wales, calculated using RdSAP, is SAP61, which is the bottom of EPC band D³. The Welsh Government has described Welsh homes as among the oldest and least energy efficient in Europe⁷, and separately as the oldest and least thermally efficient housing in the UK and Europe².

The headline distribution figure is that 63% of Welsh housing stock was graded EPC Band D or below in 2022⁵. A separate 2022 figure puts 25% of Welsh housing stock as pre-dating 1900, the largest proportion in the UK⁵. Tenure matters as much as age: owner occupiers account for the greater part of housing stock at 70%, with registered social landlord stock at 10%⁸. Social housing performs best on EPC, having the highest percentage of dwellings in EPC bands C or above, while 55% of flats had an EPC band C and above, against 25% of houses⁹.

The survey basis for much of this is the Welsh Housing Conditions Survey (WHCS) 2017-2018, whose purpose was to provide an estimate of the condition and energy efficiency and performance of the housing stock in Wales¹⁰. It assessed dwellings against the Housing, Health and Safety Rating System (HHSRS) and the Welsh Housing Quality Standard (WHQS)¹⁰. The age and condition figures above are drawn from that survey, so they describe the stock as measured in 2017-2018 rather than today.

EPC coverage: what the data shows and what it doesn't

Every EPC figure on this page comes with a coverage caveat that the statistics themselves state plainly: these statistics do not cover the entire building stock across England and Wales¹¹. That is not a technicality. It means the EPC record is a sample of the stock, weighted towards homes that have been sold, let or newly built, and it is the only large-scale measured dataset available.

The coverage estimates differ by method and by date. Measured against Census 2021 housing stock, EPCs cover around 60% of the housing stock in England and around 55% in Wales¹². A later release puts it higher: EPCs cover around 71% of the housing stock in England and around 67% in Wales¹³. A 2023 release sits between the two, at just less than 60% in Wales¹⁴. The most recent ONS analysis states that 67% in Wales had at least one EPC registration since records began in 2007, as of March 2025⁴. The gap between the 55% and 67% figures reflects different denominators and different counting rules, and both are in circulation.

Coverage is not evenly spread across the stock. A much smaller proportion of dwellings built before 1930 were covered by an EPC (58%), compared with dwellings built since 2012 (90%)⁴. The homes least likely to have a measured rating are the older, harder-to-treat ones that most need one.

There are further exclusions. The Rent Smart Wales dashboard does not include properties on the Rent Smart Wales database where the address data is insufficient to match with an EPC¹⁵. New house building data does not include information from other private approved inspectors, likely resulting in an undercount in the total number of new dwellings started and completed in Wales¹⁶. Any count of Welsh homes, and any count of Welsh EPCs, is therefore a floor rather than a total.

EPC ratings across Wales: why the stock lags behind

The distribution of ratings in Wales is shaped by three things: the age of the stock, the dominance of solid-wall construction in the oldest tranche, and the tenure mix. The 63% of Welsh housing graded EPC Band D or below in 2022 is the summary figure⁵. The average dwelling sits at SAP61, the bottom of band D³.

Lodgement volumes give a sense of how slowly the picture moves. In the 12 months to March 2023, in Wales, 80,000 domestic EPCs were lodged, a 6% decrease on the previous 12 months¹⁴. From July to September 2023, 20,000 EPCs were lodged on the Register covering domestic properties, a 3% decrease compared to the same quarter in 2022, when there were 21,000 domestic lodgements¹⁷. In the quarter April to June 2025, 2,000 EPCs were lodged for new dwellings in Wales, a 5% decrease¹². These are transaction-driven numbers: an EPC is generally produced when a home is sold, let or built, not on a fixed cycle.

Where the ratings fall within a quarter varies by property type. In Wales, from July to September 2023, the majority of new properties were given a B EER (66%), while existing dwellings were more likely to receive a C (44%) or D (36%) rating¹⁷. In the quarter April to June 2025, existing dwellings were more likely to receive a C (47%) or D (33%) rating¹². The pattern is consistent: new build clusters at the top of the scale, the existing stock clusters around C and D.

Heat pump presence in the EPC record is small. Of properties with EPCs, 1.4% of properties in England and 1.5% in Wales have heat pumps⁴. That is a measure of what is recorded on certificates, not a count of installed systems, but it indicates how little of the Welsh stock has moved to a low carbon heat source.

For a household, the EPC band is a rough proxy for running cost and for what retrofit work is likely to be needed. It is not a statement about the household's behaviour, and it does not capture appliances, tariffs or occupancy. It captures the building.

New builds: median EPC score up from 81 to 84

New build performance in Wales has improved, and the improvement is measurable. In Wales, median EPC scores for new dwellings increased from 81 to 84, comparing the five-year period to March 2013 with the five-year period to March 2025⁴. Across England and Wales, properties built after 2012 had a higher median EPC score (84) than homes built before 2012⁴. In both England and Wales, new builds in urban, larger rural and smaller rural areas all had a median EPC rating of 84⁴.

The most recent quarterly data shows how tightly new build clusters at the top of the scale. In the quarter January to March 2026, 92% of new domestic properties in Wales received an energy efficiency rating of A or B, and the majority of new dwellings were given an A EER (55%)¹³. In the quarter April to June 2025, 90% of new domestic properties received an energy efficiency rating of A or B, with 9% rated C or D, and the majority of new dwellings were given a B EER (44%)¹². Earlier quarters show the same shape: from January to March 2023, 84% of new domestic properties received an A or B rating¹⁴, and from July to September 2023, 87% did¹⁷.

Volumes have moved around. In the 12 months to March 2026, 8,000 EPCs were lodged for new dwellings in Wales, including new builds, conversions and change of use, a 19% increase on the previous year, while in the quarter January to March 2026, 2,000 were for new dwellings, a 43% increase¹³. In the 12 months to June 2025, 7,000 EPCs were lodged for new dwellings in Wales, a 9% decrease on the previous year¹². Local spikes occur: the local authority with the largest increase in EPCs lodged for new dwellings compared to the same quarter in 2024 was Conwy, at 367%¹², and in an earlier quarter the largest increase was in Blaenau Gwent, at 400%¹⁴.

The policy direction behind this is explicit. The Welsh Government has committed to build 20,000 high quality, low carbon homes for rent over the next five years¹⁸, and has set out that all new homes in Wales will be heated and powered from clean energy sources¹⁹. Improved energy efficiency from 2020 was expected to lead to a 37% reduction in CO2 from new dwellings, compared with the standards then current¹⁹.

The Warm Homes Programme: Nest and Arbed

The Welsh Government's Warm Homes Programme has been the main delivery route for improving the existing stock, and it has run through two distinct mechanisms. Nest is the Welsh Government's demand led scheme designed to tackle fuel poverty in Wales²⁰. Arbed was the area-based counterpart, working at street and estate level. By the end of March 2020, investment of more than £366m in the Warm Homes Programme (Nest and Arbed) had improved the energy efficiency of more than 61,400 homes in Wales, drawing on European, UK and Welsh Government funding⁶.

Nest's scale and reach are documented year by year. In 2016/17, the Welsh Government provided £19.5m for Nest²¹. The scheme has also leveraged funding from other sources: it leveraged an additional £4.2m of ECO funding into Wales as of September 2014²⁰. Nest provides all householders in Wales with access to advice and support to help them reduce their energy bills²¹, and the advice service is available to all households in Wales²².

The scheme's purpose is targeted rather than universal in its improvement work. It is designed to help households facing an immediate risk to their health and wellbeing due to a lack of essential heating or hot water²³. The Welsh Government offers free energy upgrades through the Warm Homes Nest Scheme for houses with a poor Energy Performance Certificate rating²⁴. Nest is not identical to ECO or GBIS, the UK-wide schemes, and operates on its own eligibility rules²⁵.

Arbed, by contrast, is closed. Its successor arrangements and the wider grant landscape are set out in why energy grants differ by nation, and the Arbed programme itself is covered in Arbed: the closed Welsh scheme.

Nest: who qualifies and what is funded

Nest eligibility has two routes, and the health route carries a specific EPC threshold. To be eligible, a home must have an EPC rating of D or lower (SAP score 68 or lower), and someone in the household must have a qualifying health condition²². The scheme looks to support people in Wales living on a lower income who receive a means tested benefit or live with a respiratory, circulatory or mental health condition²⁶. An earlier statement of the rules described the scheme as offering a package of free home energy improvement measures to households who are in receipt of a means tested benefit who live in a very energy inefficient home, with a SAP rating of F or G²⁰.

What is funded is a package rather than a single measure. This includes a referral for eligible householders for a package of free home energy efficiency measures such as a new boiler, central heating system, loft or cavity wall insulation, or renewable technologies²¹. More recent guidance describes replacement of boiler or electric storage heaters to ensure you have a safe and reliable heating system²³. The Nest scheme offers a range of free, impartial advice as part of the Welsh Government Warm Homes fund²⁷.

Private landlords face an additional condition. Nest works in partnership with Rent Smart Wales to ensure all private landlords are officially registered before being allowed access to support¹⁶. A consultation on a future demand-led fuel poverty scheme to succeed Nest proposed amending eligibility to exclude private landlords²⁸. Separately, an EPC rating of E or above is required on domestic private rented property in Wales in order to comply with the law²⁷.

Outcomes are recorded after installation. Around two thirds (66%) of households moved up to band C, among the 232 homes with a recorded post-installation rating in the period 1 October 2024 to 31 March 2025²². In 2022-23, 23.2% of households had a SAP rating of C, 60.2% rated D, 13.7% rated E and 2.9% rated F¹⁶.

Quality assurance and the Wales-based installer network

Delivery under Nest runs through a defined installer base. A network of Wales-based installers provided the installation services under the management of the Nest team²². In 2022-23, 100% of installations were completed by Wales-based installers¹⁶. That is a deliberate feature of the scheme rather than an incidental one: it keeps the supply chain, the training and the warranty relationship inside Wales.

The advice side has its own reach figures. A direct mail campaign reached 154,764 vulnerable households in Wales in the period 1 April 2024 to 31 March 2025²². All households in Wales also have access to free, impartial advice to help reduce energy bills and maximise income³⁰. The Nest advice service is available to all households in Wales, whether or not they go on to receive physical measures²².

Complaints and customer service are handled through the same advice line. The Nest advice team can be contacted on 0808 808 2244 to log a complaint, and the customer service manager can be reached at advicewales@est.org.uk or on the same number²⁹. The scheme publishes a customer service and complaints policy²⁹.

For a household, the installer network matters for two reasons. First, it determines who carries out the work and therefore who holds the workmanship guarantee. Second, it means the practical quality question is about a Welsh supply chain rather than a national one. The Welsh Government's own resident engagement work, through the Active Building Centre case study, records how retrofit programmes are experienced by residents⁸.

What the CCC's 73% carbon budget means for Welsh homes

The Climate Change Committee recommended in May 2025 that Wales' Fourth Carbon Budget, covering 2031 to 2035, be set at an average annual reduction of 73% on 1990 levels, with the Welsh Government to set the budget by the end of 2025³¹. That is the figure against which Welsh housing policy now has to be judged, and it is a steepening of an already demanding trajectory.

The existing targets are substantial in their own right. In 2019, the UK Committee on Climate Change stated that Welsh Government should target no less than a 95% reduction in carbon emissions by 2050, against 1990 levels³. Housing currently produces 21% of Welsh carbon emissions³. The decarbonisation programme requires Welsh homes to have reduced carbon demand by 80% by 2050⁸. Other Welsh Government statements put the residential share differently: residential emissions make up 10% of all carbon emissions in Wales¹⁸, and new and existing homes currently account for 9% of Welsh greenhouse gas emissions¹⁹.

The policy instruments attached to these targets are already visible. The Welsh Housing Quality Standard has required social homes to reach not less than EPC D, with a new standard looking at a target of an A rating⁶. Short term UK energy efficiency targets, such as MEES requiring EPC C for private rented housing, need to go further according to the Welsh Government's own decarbonisation strategy³. The Welsh Government has also consulted on a heat strategy for Wales⁷.

For a household, the direction of travel is that the building fabric and the heat source are both in scope, and that the standards applied to social and private rented homes are tightening ahead of those applied to owner-occupied homes. The full picture of Welsh carbon budgets is set out in Wales' carbon budgets and net zero target, and the way Welsh homes are heated is covered in how Welsh homes are heated.