Solar panel installation in Cardiff

Serving Cardiff and the wider South Glamorgan area, including Penarth, Caerphilly, Barry.

First things first: solar planning rules in Wales are not England’s

If you own a home in Cardiff and you’ve been researching solar online, there’s a good chance most of what you’ve read is quietly wrong for you — because the majority of UK solar content describes English planning law. Cardiff sits under the Welsh planning system, which runs its own permitted development rules. Wales grants permitted development for domestic solar under its own Order (the 1995 GPDO as amended for Wales — Part 40 covers microgeneration on houses and flats), and its conditions are not the same as England’s: panels should not rise above the ridgeline, should project no more than 200 mm from the roof or wall surface, and must be sited, so far as practicable, to minimise the effect on the building’s appearance. Listed buildings and conservation areas carry further restrictions, and non-domestic buildings have their own route (Part 43).

One difference worth being blunt about: England rewrote its solar permitted development rules from 27 August 2026 (SI 2026/896) — among other things allowing wall-mounted panels on a house to project up to 0.4 m and explicitly covering plug-in solar kits. That rewrite is English law and does not apply in Cardiff. In Wales the Part 40 conditions stand as they are, and any installer quoting you the English rules hasn’t done their homework. The good news is that a standard on-roof array on rails sits comfortably within 200 mm on most pitched roofs, so for the typical Cardiff house the practical answer is still “no planning application needed” — but the rule being met is the Welsh one, and your installer should confirm your specific position in writing at survey. When in doubt, Cardiff Council’s planning service and the Welsh Government’s own solar planning guidance are the authorities, not an England-centric blog.

The coal money built Cardiff’s roofs — and they shape every install

Cardiff’s housing stock is a direct product of its coal boom. As the port grew into one of the world’s great coal-exporting harbours in the decades before 1914, street after street of Victorian and Edwardian terraces went up to house the workforce — and those terraces still make up an enormous share of the city’s homes.

Victorian and Edwardian terraces — Roath, Cathays, Canton, Grangetown, Splott and Adamsdown. Roofs are predominantly natural slate, often now interleaved with later concrete retiles, and the install questions are the classic terrace set: slate-competent fixings (hooks or dressed slates, never adhesive shortcuts), rear-slope arrays where the front faces the street, and a scaffold plan settled at survey — front-elevation scaffold on a Cathays street usually means standing on the public footway, which needs council consent arranged in advance. Cathays and Roath also carry one of the UK’s densest student rental markets; if you’re a landlord considering solar on an HMO, the electrical condition of the installation (and the consumer unit) belongs in the quote conversation from day one.

Edwardian villas and the conservation set. Cardiff has 27 conservation areas, and the ones that come up most for solar are Cathedral Road — the great avenue of Victorian villas west of the river, with its own council appraisal — and Llandaff, the cathedral village that still reads as a settlement in its own right. Rhiwbina Garden Village, begun in 1912 to a masterplan by Raymond Unwin and a conservation area since 1976, is a special case: a planned garden suburb where roofline uniformity is the whole point, so expect the council to care about visibility. In all three, the realistic solar routes are rear or concealed slopes, or a flush in-roof installation at re-roof time — which on slate-roofed period stock is often the best answer anyway, because it replaces the tired slates and the panels in one scaffold hire.

Interwar and post-war suburbs. Whitchurch, Rhiwbina (outside the Garden Village core), Heath and Cyncoed carry solid 1930s semi stock — simple pitches, accessible lofts, tile rather than slate, the easiest installs in the city. The post-war expansion west and east — Ely, Caerau, Llanrumney, Rumney — adds large estate stock, much of it now owner-occupied, with regular roof forms that take standard fixings well. On the newest stock, Pontprennau and St Mellons’ modern estates include houses already built with PV or cabling provision; a survey establishes what’s reusable.

Who runs Cardiff’s wires: NGED South Wales

Cardiff’s distribution network operator is National Grid Electricity Distribution (South Wales) — the network company, not your supplier, and the counterparty for connection paperwork. The two routes are the same as everywhere in Britain: up to 16 A per phase (about 3.68 kW of inverter output), the installer connects and notifies within 28 days under G98; anything larger — including most solar-plus-battery systems — requires a G99 application approved before energisation, and the DNO can set an export limit. Domestic-scale G99 approvals are typically a matter of weeks, but the sequencing discipline is the tell of a well-run installer: application in at survey stage, approval in hand before the scaffold goes up. “We’ll sort the grid stuff after” is how systems end up export-limited or turned down.

What Cardiff Council and the Welsh Government bring to the table

Cardiff Council works to its One Planet Cardiff strategy with a 2030 net-zero ambition, and the Welsh Government has set a net-zero target for the whole Welsh public sector by 2030 — which is why solar is appearing on schools, leisure centres and depots across the city. For homeowners the honest translation is: a supportive planning culture, no general council grant for owner-occupier panels, and the same national levers as the rest of Great Britain — 0% VAT on domestic installation until 31 March 2027, and Smart Export Guarantee payments (roughly 12–16p/kWh on current leading tariffs) once your MCS certificate is issued. For smaller commercial owners, Business Wales support schemes are worth a conversation, and the public-sector 2030 mandate means Welsh commercial supply chains increasingly ask about suppliers’ own emissions — a quiet commercial reason some Cardiff firms fit panels.

Honest yield expectations for a Cardiff roof

UK domestic systems generate roughly 850–1,050 kWh per installed kWp per year. Cardiff’s position on the Severn Estuary in the southern half of Britain puts it in the middle-to-upper part of that band — a well-oriented, unshaded 4 kWp array can reasonably be expected to produce somewhere around 3,500–4,000 kWh annually. We won’t pretend to a city-precise figure, because none exists that survives contact with a real roof: orientation, pitch and the chimney shading a rear slope in Canton matter far more than which side of the Severn you live on. A proper survey models your roof; treat brochure yield promises with the scepticism they deserve.

What installation costs — and why we won’t invent a “Cardiff price”

The most robust public benchmark is MCS-reported installation data, which puts the England average at about £1,565–£1,590 per kW as of spring 2026; regional labour typically moves real quotes 10–15% either side, and South Wales quotes generally sit close to that band. System-size tables, battery pricing and the anatomy of a quote live in our cost guide — the honest headline is that a typical 3.5–6 kWp domestic install lands in the £5,500–£11,000 range nationally, with slate labour and scaffold access the lines that move Cardiff terrace quotes most. Domestic installs carry 0% VAT until 31 March 2027. On period stock, remember the re-roof arithmetic: if your slate roof has a decade or less left, integrating panels during the re-roof is markedly cheaper than paying for scaffold twice.

A Cardiff scenario: Roath terrace, re-roof plus in-roof array

A scenario to make it concrete — not a case study. An Edwardian terrace in Roath, rear slope facing south-east, original slate roof now past its best. Rather than fixing panels to failing slate, the owner re-roofs: an in-roof tray system replaces the covering beneath a 4.8 kWp array, flashing detail owned by the roofing contractor, panels finishing flush with the new slate line. The flush profile sits well inside the Welsh 200 mm projection rule, and the visual result is the kind that keeps conservation-minded neighbours friendly. The inverter goes in the understairs cupboard; kept at 3.68 kW output, the connection is a straightforward G98 notification to NGED South Wales after commissioning. Roof and trays: three days within the wider re-roof. The marginal cost of the solar was far below a standalone install two years later — the re-roof moment is the cheapest solar this house will ever buy.

Cardiff postcode districts covered

• CF10 — city centre, Cathays Park and Cardiff Bay; flats and commercial stock where solar is a building-owner decision
• CF11 — Grangetown, Riverside and Pontcanna; coal-era terraces, with the Cathedral Road conservation area on the district’s edge
• CF24 — Roath, Cathays, Splott and Adamsdown; the densest terrace territory in the city, rear-slope installs the norm
• CF3 — Rumney, St Mellons and Old St Mellons; post-war estates plus modern stock with some PV-ready builds
• CF5 — Canton, Fairwater, Ely, Caerau and Llandaff; everything from terraces to estate semis, with Llandaff’s conservation core needing early planning checks
• CF14 — Whitchurch, Rhiwbina, Llanishen and Heath; prime 1930s semi country, plus the Rhiwbina Garden Village conservation area
• CF15 — Radyr, Tongwynlais, Taff’s Well and Pentyrch; village-edge stock where ground-mount questions occasionally arise
• CF23 — Cyncoed, Lakeside, Pentwyn and Pontprennau; interwar villas through to modern estates
• CF1 — a note for accuracy: CF1 was Cardiff’s old central district code, retired in 1999 when the centre was recoded to CF10 and CF11; if your paperwork says CF1, you’re covered under the newer districts

Neighbouring coverage and nearby cities

We cover the whole Cardiff hinterland — Penarth, Barry, Caerphilly and Pontypridd included — and the installation-first approach continues in our guides for Bristol, Swindon and Birmingham.

Cardiff questions we’re asked most

Are solar planning rules really different in Wales?

Yes. Wales runs its own permitted development regime (Part 40 of the Welsh GPDO for homes), with a 200 mm projection limit, a no-higher-than-the-ridge rule, and a duty to minimise visual impact. England’s 27 August 2026 rule changes (SI 2026/896) do not apply here. Most standard Cardiff installs still proceed without a planning application — but under the Welsh conditions, which your installer should confirm in writing.

Do I need permission in Llandaff, Cathedral Road or Rhiwbina Garden Village?

Treat all three as “check first”. They are conservation areas — three of Cardiff’s 27 — and visibility from the street is the deciding factor the council will weigh. Rear slopes, concealed elevations and in-roof systems at re-roof time are the designs that succeed. Listed buildings (Llandaff has several) always need consent.

Who is the DNO for Cardiff, and what do they actually do?

National Grid Electricity Distribution (South Wales). They own the wires, approve or take notification of your connection (G98 under 16 A per phase, G99 above — approval before switch-on), and can set export limits on larger systems. Your installer, not you, should run this process, and should be able to tell you which route your system takes before you sign.

My terrace has its original slate roof. On-roof or in-roof?

If the slate is sound with decades left: on-roof, with slate hooks, an experienced crew and a breakage allowance. If the roof is within ten years of replacement: seriously consider re-roofing with an in-roof array — one scaffold, new weathertight covering, flush finish, and a lower combined cost than doing the jobs separately.

Does Cardiff weather undermine the case for solar?

No — payback is driven by the electricity you stop importing (worth ~26p/kWh at current prices) far more than by peak sunshine. Cardiff sits in the middle-to-upper part of the UK’s 850–1,050 kWh/kWp range. The genuine yield killers are shading and poor orientation, which is why the survey matters more than the city.

When you’re ready for real numbers: see typical costs and payback or request a free quote — no pressure, and a straight answer if your roof doesn’t suit.