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Solar panel cost in Carmarthenshire (SA34)

See realistic solar installation costs, savings and payback for SA34 (Carmarthenshire) in under a minute using official UK data. Start with the calculator, then get a no-obligation quote from an MCS-certified installer. You can also ask the SolarByPostcode assistant to sanity-check your roof, bills and plans.

Solar Calculator

Change the settings below to see how costs and savings work for your situation.

System Size

Roof Direction

Battery Storage

Export Value

Your Numbers

Break-even
9.9 years
After this, it's pure profit
Upfront Cost
£9,767
What you pay to get started
Annual Benefit
£987
What you save every year
Profit Over 25 Years
£14,897
After paying itself off, you're this much ahead

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How we calculate this

Solar generation: Based on typical south-facing roof at 35° angle. We account for weather, dirt, and system losses (14%).

How much you'll use directly:

  • Without battery: You'll use about 40% of what you generate. The rest gets sold back to the grid.
  • With 5 kWh battery: You'll use about 70% (battery stores extra for evening use).
  • With 10 kWh battery: You'll use about 75% (more storage means less exported).
  • Panel-only payback: The official cost per kW is lower above 4 kW, so a 5–6 kW system can pay back a little faster than a 3–4 kW system on otherwise identical assumptions.
  • Battery & payback: Batteries raise self-use and cut bills, but added hardware cost often lengthens break-even at typical UK rates.
  • When a battery can still make sense:
    • Evening-heavy usage patterns
    • Time-of-use tariffs / cheap night rates
    • Low export rate vs. high unit rate
    • Heat pump or EV charging synergy
    • Optional backup/resilience (system-dependent)
    • Lower evening-hour CO₂ vs. grid

Panel costs: Uses March 2026 TIC mean installation costs: £1,827/kW up to 4 kW and £1,628/kW above 4 kW.

Other costs: Battery prices are modelled at £700 per kWh. Export tariffs vary by supplier (usually 5–15p per kWh).

Grid connection: Systems up to about 3.7 kW typically need just a notification (G98). Larger systems may need permission (G99).

These are typical values based on average usage patterns. Your actual results will vary based on your roof, shading, and how you use electricity.

Your area in context

In South Wales, the current unit rate is 26.33p/kWh with a 57.84p/day standing charge. Your postcode’s south-facing sunshine yield is 995 kWh/kW — 26 above the regional median (968).

Read the full story

A typical roof here lands around 6.0 kW, with most eligible homes comfortably fitting within 3–6 kW. Each kilowatt of panels produces roughly 995 kWh per year on a south-facing roof. We value self-used electricity at 26.3p and exported surplus at a baseline 10p via SEG. Use the calculator above for your exact tariff.

Unit rate
26.3p/kWh
Standing charge
57.8p/day
Sunshine yield (south)
995 kWh/kW
Export price (baseline)
10p/kWh

Browse the scenarios below. Each battery size has its own expand — open the one that matches your plan (or just explore). For each system size (2–8 kW) we show annual output, how much you use directly, what gets exported, annual benefit, upfront cost, break-even, and a 20-year net. Negative numbers are possible — that’s the honest trade-off when adding more battery than your usage profile justifies.

No battery 5 kW example → Annual benefit: £822, Upfront: £8,139, Break-even: 9.9 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1989 kWh 796 kWh 1193 kWh £209 £119 £329 £3,256 9.9 yrs £3,321
3 kW 2984 kWh 1193 kWh 1790 kWh £314 £179 £493 £4,883 9.9 yrs £4,982
4 kW 3978 kWh 1591 kWh 2387 kWh £419 £239 £658 £6,511 9.9 yrs £6,643
5 kW 4973 kWh 1989 kWh 2984 kWh £524 £298 £822 £8,139 9.9 yrs £8,303
6 kW 5967 kWh 2387 kWh 3580 kWh £628 £358 £987 £9,767 9.9 yrs £9,964
7 kW 6962 kWh 2785 kWh 4177 kWh £733 £418 £1,151 £11,394 9.9 yrs £11,625
8 kW 7956 kWh 3183 kWh 4774 kWh £838 £477 £1,315 £13,022 9.9 yrs £13,285

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,628, battery £/kWh = 700.

3 kWh battery 5 kW example → Annual benefit: £985, Upfront: £10,239, Break-even: 10.4 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1989 kWh 1193 kWh 796 kWh £314 £80 £394 £5,356 13.6 yrs £2,521
3 kW 2984 kWh 1790 kWh 1193 kWh £471 £119 £591 £6,983 11.8 yrs £4,831
4 kW 3978 kWh 2387 kWh 1591 kWh £628 £159 £788 £8,611 10.9 yrs £7,141
5 kW 4973 kWh 2984 kWh 1989 kWh £786 £199 £985 £10,239 10.4 yrs £9,451
6 kW 5967 kWh 3580 kWh 2387 kWh £943 £239 £1,181 £11,867 10.0 yrs £11,762
7 kW 6962 kWh 4177 kWh 2785 kWh £1,100 £278 £1,378 £13,494 9.8 yrs £14,072
8 kW 7956 kWh 4774 kWh 3183 kWh £1,257 £318 £1,575 £15,122 9.6 yrs £16,382

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,628, battery £/kWh = 700.

5 kWh battery 5 kW example → Annual benefit: £1,066, Upfront: £11,639, Break-even: 10.9 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1989 kWh 1392 kWh 597 kWh £367 £60 £426 £6,756 15.8 yrs £1,770
3 kW 2984 kWh 2089 kWh 895 kWh £550 £90 £639 £8,383 13.1 yrs £4,405
4 kW 3978 kWh 2785 kWh 1193 kWh £733 £119 £853 £10,011 11.7 yrs £7,040
5 kW 4973 kWh 3481 kWh 1492 kWh £917 £149 £1,066 £11,639 10.9 yrs £9,676
6 kW 5967 kWh 4177 kWh 1790 kWh £1,100 £179 £1,279 £13,267 10.4 yrs £12,311
7 kW 6962 kWh 4873 kWh 2089 kWh £1,283 £209 £1,492 £14,894 10.0 yrs £14,946
8 kW 7956 kWh 5570 kWh 2387 kWh £1,466 £239 £1,705 £16,522 9.7 yrs £17,581

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,628, battery £/kWh = 700.

7.5 kWh battery 5 kW example → Annual benefit: £1,090, Upfront: £13,389, Break-even: 12.3 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1989 kWh 1452 kWh 537 kWh £382 £54 £436 £8,506 19.5 yrs £215
3 kW 2984 kWh 2178 kWh 806 kWh £573 £81 £654 £10,133 15.5 yrs £2,948
4 kW 3978 kWh 2904 kWh 1074 kWh £765 £107 £872 £11,761 13.5 yrs £5,680
5 kW 4973 kWh 3630 kWh 1343 kWh £956 £134 £1,090 £13,389 12.3 yrs £8,413
6 kW 5967 kWh 4356 kWh 1611 kWh £1,147 £161 £1,308 £15,017 11.5 yrs £11,145
7 kW 6962 kWh 5082 kWh 1880 kWh £1,338 £188 £1,526 £16,644 10.9 yrs £13,878
8 kW 7956 kWh 5808 kWh 2148 kWh £1,529 £215 £1,744 £18,272 10.5 yrs £16,611

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,628, battery £/kWh = 700.

10 kWh battery 5 kW example → Annual benefit: £1,106, Upfront: £15,139, Break-even: 13.7 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1989 kWh 1492 kWh 497 kWh £393 £50 £443 £10,256 23.2 yrs £-1,405
3 kW 2984 kWh 2238 kWh 746 kWh £589 £75 £664 £11,883 17.9 yrs £1,393
4 kW 3978 kWh 2984 kWh 995 kWh £786 £99 £885 £13,511 15.3 yrs £4,190
5 kW 4973 kWh 3730 kWh 1243 kWh £982 £124 £1,106 £15,139 13.7 yrs £6,988
6 kW 5967 kWh 4476 kWh 1492 kWh £1,178 £149 £1,328 £16,767 12.6 yrs £9,785
7 kW 6962 kWh 5221 kWh 1740 kWh £1,375 £174 £1,549 £18,394 11.9 yrs £12,583
8 kW 7956 kWh 5967 kWh 1989 kWh £1,571 £199 £1,770 £20,022 11.3 yrs £15,380

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,628, battery £/kWh = 700.

13.5 kWh battery 5 kW example → Annual benefit: £1,123, Upfront: £17,589, Break-even: 15.7 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1989 kWh 1532 kWh 457 kWh £403 £46 £449 £12,706 28.3 yrs £-3,725
3 kW 2984 kWh 2297 kWh 686 kWh £605 £69 £674 £14,333 21.3 yrs £-863
4 kW 3978 kWh 3063 kWh 915 kWh £807 £91 £898 £15,961 17.8 yrs £2,000
5 kW 4973 kWh 3829 kWh 1144 kWh £1,008 £114 £1,123 £17,589 15.7 yrs £4,862
6 kW 5967 kWh 4595 kWh 1372 kWh £1,210 £137 £1,347 £19,217 14.3 yrs £7,725
7 kW 6962 kWh 5361 kWh 1601 kWh £1,411 £160 £1,572 £20,844 13.3 yrs £10,587
8 kW 7956 kWh 6126 kWh 1830 kWh £1,613 £183 £1,796 £22,472 12.5 yrs £13,450

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 1,628, battery £/kWh = 700.

Figures are illustrative and use the same method as the calculator above. For exact results, adjust your roof direction, tariff, and usage in the calculator.

Before you request quotes in Carmarthenshire

Use the numbers above to sanity-check installer quotes. The main things to compare are system size, battery assumptions, payback claims, MCS certification, DNO paperwork and export assumptions.

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Understand DNO, G98 and G99 export limits

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Insights for SA34

Figures below are tailored to SA34 — click through for full league tables.

Big-Roof Britain Rank #71 of 2182
6.8 kWp (UK avg 5.1 kWp)
~14 panels (≈430 W)
Solar Payback Index Rank #926 of 2996
9.9 years (UK avg 10.8 years)
~£987 /yr • £9,767 upfront
Standing-Charge Drag Rank #783 of 2996
21.4% (UK avg 26.6%) drag on savings
£211 fixed • ~£987 /yr value
Aspect Penalty View ranking →
East −18.9% West −21.0%
Typical output loss versus a south-facing roof (lower is better)

Seasonal solar output in SA34

Monthly generation per kilowatt of solar panels

kWh 36 Jan 53 Feb 86 Mar 116 Apr 126 May 125 Jun 120 Jul 108 Aug 90 Sep 61 Oct 42 Nov 31 Dec
Best month Worst month Winter (Dec–Feb) Other months

Winter output: 48.4% of an average month (Dec–Feb)

Best / worst month: May / Dec

These figures show output per kilowatt (kW) of panels installed. In winter, a 1 kW system here produces about 40 kWh per month; the average month produces around 83 kWh. So a typical 4 kW home system would generate roughly 160 kWh in winter, or 332 kWh in an average month.

Your Area at a Glance

Your Electricity Rate
26.33p/kWh
Daily Fixed Charge
57.84p/day
Local Sunshine
995kWh/kW
A 1 kW system generates ~995 kWh per year. A typical home uses ~2,700 kWh per year.
Typical System Size
6.0kW
For houses & bungalows in this area

Local Property Data

Property Types

Houses: 64% • Flats: 11% • Bungalows: 24% Based on 1,322 properties

Coverage

Carmarthenshire (87%)|Pembrokeshire (13%)

Areas Covered

Whitland, Llanboidy, Laugharne Township, Trelech, Lampeter Velfrey, Crymych and Mynachlog-ddu, Amroth and Saundersfoot North

Data Sources & Assumptions

Solar yield: PVGIS (EU Joint Research Centre), January 2025 data

Electricity rates: Ofgem price cap, Q3 2026

Installation costs: DESNZ/MCS data, March 2026 (TIC)

Property data: EPC open data (Open Government Licence), aggregated

All estimates are typical values. Actual results vary based on your specific situation, roof characteristics, and usage patterns.

Compare nearby areas

Nearby in South Wales

SA66 (Pembrokeshire)
≈8.7 km away
Local sunshine: ~957 kWh/kWp · -4% vs SA34
SA67 (Pembrokeshire)
≈9.9 km away
Local sunshine: ~972 kWh/kWp · -2% vs SA34
SA33 (Carmarthenshire)
≈11.2 km away
Local sunshine: ~992 kWh/kWp · -0% vs SA34
SA36 (Pembrokeshire)
≈12.7 km away
Local sunshine: ~935 kWh/kWp · -6% vs SA34
SA35 (Pembrokeshire)
≈14.5 km away
Local sunshine: ~915 kWh/kWp · -8% vs SA34
SA68 (Pembrokeshire)
≈15.2 km away
Local sunshine: ~1,014 kWh/kWp · +2% vs SA34

Similar sunshine across the UK

TW10 (Richmond upon Thames)
~995 kWh/kWp · +0% vs SA34
IP24 (Breckland)
~995 kWh/kWp · +0% vs SA34
RG2 (Reading)
~995 kWh/kWp · +0% vs SA34