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Solar panel cost in Carmarthenshire (SA39)

See realistic solar installation costs, savings and payback for SA39 (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
15.0 years
After this, it's pure profit
Upfront Cost
£12,207
What you pay to get started
Annual Benefit
£816
What you save every year
Profit Over 25 Years
£8,205
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: Bigger systems don’t shorten payback—cost and savings rise together per kW.
  • 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

Costs: Battery prices are typically £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 23.31p/kWh with a 56.85p/day standing charge. Your postcode’s south-facing sunshine yield is 888 kWh/kW — 80 below 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 888 kWh per year on a south-facing roof. We value self-used electricity at 23.3p and exported surplus at a baseline 10p via SEG. Use the calculator above for your exact tariff.

Unit rate
23.3p/kWh
Standing charge
56.9p/day
Sunshine yield (south)
888 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: £680, Upfront: £10,173, Break-even: 15.0 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1776 kWh 710 kWh 1066 kWh £166 £107 £272 £4,069 15.0 yrs £1,374
3 kW 2664 kWh 1066 kWh 1598 kWh £248 £160 £408 £6,104 15.0 yrs £2,061
4 kW 3552 kWh 1421 kWh 2131 kWh £331 £213 £544 £8,138 15.0 yrs £2,748
5 kW 4440 kWh 1776 kWh 2664 kWh £414 £266 £680 £10,173 15.0 yrs £3,435
6 kW 5328 kWh 2131 kWh 3197 kWh £497 £320 £816 £12,207 15.0 yrs £4,122
7 kW 6216 kWh 2486 kWh 3730 kWh £580 £373 £953 £14,242 15.0 yrs £4,809
8 kW 7104 kWh 2842 kWh 4262 kWh £662 £426 £1,089 £16,276 15.0 yrs £5,497

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

3 kWh battery 5 kW example → Annual benefit: £799, Upfront: £12,273, Break-even: 15.4 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1776 kWh 1066 kWh 710 kWh £248 £71 £319 £6,169 19.3 yrs £220
3 kW 2664 kWh 1598 kWh 1066 kWh £373 £107 £479 £8,204 17.1 yrs £1,380
4 kW 3552 kWh 2131 kWh 1421 kWh £497 £142 £639 £10,238 16.0 yrs £2,539
5 kW 4440 kWh 2664 kWh 1776 kWh £621 £178 £799 £12,273 15.4 yrs £3,699
6 kW 5328 kWh 3197 kWh 2131 kWh £745 £213 £958 £14,307 14.9 yrs £4,859
7 kW 6216 kWh 3730 kWh 2486 kWh £869 £249 £1,118 £16,342 14.6 yrs £6,019
8 kW 7104 kWh 4262 kWh 2842 kWh £994 £284 £1,278 £18,376 14.4 yrs £7,179

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

5 kWh battery 5 kW example → Annual benefit: £858, Upfront: £13,673, Break-even: 15.9 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1776 kWh 1243 kWh 533 kWh £290 £53 £343 £7,569 22.1 yrs £-708
3 kW 2664 kWh 1865 kWh 799 kWh £435 £80 £515 £9,604 18.7 yrs £689
4 kW 3552 kWh 2486 kWh 1066 kWh £580 £107 £686 £11,638 17.0 yrs £2,085
5 kW 4440 kWh 3108 kWh 1332 kWh £724 £133 £858 £13,673 15.9 yrs £3,481
6 kW 5328 kWh 3730 kWh 1598 kWh £869 £160 £1,029 £15,707 15.3 yrs £4,877
7 kW 6216 kWh 4351 kWh 1865 kWh £1,014 £186 £1,201 £17,742 14.8 yrs £6,274
8 kW 7104 kWh 4973 kWh 2131 kWh £1,159 £213 £1,372 £19,776 14.4 yrs £7,670

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

7.5 kWh battery 5 kW example → Annual benefit: £875, Upfront: £15,423, Break-even: 17.6 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1776 kWh 1296 kWh 480 kWh £302 £48 £350 £9,319 26.6 yrs £-2,316
3 kW 2664 kWh 1945 kWh 719 kWh £453 £72 £525 £11,354 21.6 yrs £-849
4 kW 3552 kWh 2593 kWh 959 kWh £604 £96 £700 £13,388 19.1 yrs £619
5 kW 4440 kWh 3241 kWh 1199 kWh £756 £120 £875 £15,423 17.6 yrs £2,086
6 kW 5328 kWh 3889 kWh 1439 kWh £907 £144 £1,050 £17,457 16.6 yrs £3,553
7 kW 6216 kWh 4538 kWh 1678 kWh £1,058 £168 £1,226 £19,492 15.9 yrs £5,020
8 kW 7104 kWh 5186 kWh 1918 kWh £1,209 £192 £1,401 £21,526 15.4 yrs £6,487

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

10 kWh battery 5 kW example → Annual benefit: £887, Upfront: £17,173, Break-even: 19.4 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1776 kWh 1332 kWh 444 kWh £310 £44 £355 £11,069 31.2 yrs £-3,971
3 kW 2664 kWh 1998 kWh 666 kWh £466 £67 £532 £13,104 24.6 yrs £-2,457
4 kW 3552 kWh 2664 kWh 888 kWh £621 £89 £710 £15,138 21.3 yrs £-942
5 kW 4440 kWh 3330 kWh 1110 kWh £776 £111 £887 £17,173 19.4 yrs £572
6 kW 5328 kWh 3996 kWh 1332 kWh £931 £133 £1,065 £19,207 18.0 yrs £2,087
7 kW 6216 kWh 4662 kWh 1554 kWh £1,087 £155 £1,242 £21,242 17.1 yrs £3,601
8 kW 7104 kWh 5328 kWh 1776 kWh £1,242 £178 £1,420 £23,276 16.4 yrs £5,115

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

13.5 kWh battery 5 kW example → Annual benefit: £899, Upfront: £19,623, Break-even: 21.8 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1776 kWh 1368 kWh 408 kWh £319 £41 £360 £13,519 37.6 yrs £-6,327
3 kW 2664 kWh 2051 kWh 613 kWh £478 £61 £539 £15,554 28.8 yrs £-4,765
4 kW 3552 kWh 2735 kWh 817 kWh £638 £82 £719 £17,588 24.5 yrs £-3,203
5 kW 4440 kWh 3419 kWh 1021 kWh £797 £102 £899 £19,623 21.8 yrs £-1,642
6 kW 5328 kWh 4103 kWh 1225 kWh £956 £123 £1,079 £21,657 20.1 yrs £-80
7 kW 6216 kWh 4786 kWh 1430 kWh £1,116 £143 £1,259 £23,692 18.8 yrs £1,482
8 kW 7104 kWh 5470 kWh 1634 kWh £1,275 £163 £1,438 £25,726 17.9 yrs £3,044

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, 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.

Insights for SA39

Figures below are tailored to SA39 — click through for full league tables.

Big-Roof Britain Rank #38 of 2182
7.2 kWp (UK avg 5.1 kWp)
~15 panels (≈430 W)
Solar Payback Index Rank #2337 of 2997
13.3 years (UK avg 12.6 years)
~£920 /yr • £12,207 upfront
Standing-Charge Drag Rank #1132 of 2997
20.9% (UK avg 24.6%) drag on savings
£193 fixed • ~£920 /yr value
Aspect Penalty View ranking →
East −18.7% West −19.6%
Typical output loss versus a south-facing roof (lower is better)

Seasonal solar output in SA39

Monthly generation per kilowatt of solar panels

kWh 30 Jan 46 Feb 78 Mar 107 Apr 114 May 111 Jun 107 Jul 97 Aug 80 Sep 55 Oct 38 Nov 26 Dec
Best month Worst month Winter (Dec–Feb) Other months

Winter output: 46.0% 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 34 kWh per month; the average month produces around 74 kWh. So a typical 4 kW home system would generate roughly 136 kWh in winter, or 296 kWh in an average month.

Your Area at a Glance

Your Electricity Rate
23.31p/kWh
Daily Fixed Charge
56.85p/day
Local Sunshine
888kWh/kW
A 1 kW system generates ~888 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: 65% • Flats: 5% • Bungalows: 30% Based on 746 properties

Coverage

Carmarthenshire (85%)|Ceredigion (15%)

Areas Covered

Llanfihangel-ar-Arth, Llandysul South, Llandysul North and Troedyraur, Llanwenog, Llanegwad

Data Sources & Assumptions

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

Electricity rates: Ofgem price cap, Q1 2026

Installation costs: MCS certified installer data, March 2025

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

SA40 (Carmarthenshire)
≈8.8 km away
Local sunshine: ~886 kWh/kWp · -0% vs SA39
SA44 (Ceredigion)
≈9.3 km away
Local sunshine: ~893 kWh/kWp · +1% vs SA39
SA38 (Carmarthenshire)
≈15.0 km away
Local sunshine: ~922 kWh/kWp · +4% vs SA39
SA48 (Ceredigion)
≈16.2 km away
Local sunshine: ~888 kWh/kWp · +0% vs SA39
SA32 (Carmarthenshire)
≈16.6 km away
Local sunshine: ~950 kWh/kWp · +7% vs SA39
SA31 (Carmarthenshire)
≈18.6 km away
Local sunshine: ~957 kWh/kWp · +8% vs SA39

Similar sunshine across the UK

PH11 (Perth and Kinross)
~888 kWh/kWp · +0% vs SA39
PH10 (Perth and Kinross)
~888 kWh/kWp · -0% vs SA39
SY18 (Powys)
~888 kWh/kWp · -0% vs SA39