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Postcode solar briefing

Solar panel cost in Carmarthenshire (SA15)

See realistic solar installation costs, savings and payback for SA15 (Carmarthenshire) using official UK data. Start with the local verdict, then adjust the calculator for your roof, usage and export assumptions.

Local model Calculator unchanged Quote assumptions checked
Local solar briefing

Solar in SA15: roof size may be the main upside, so compare proposed system sizes carefully.

This is a modelled local view, not a promise of savings. Use it as a quick sense-check before comparing installer quotes for SA15.

Typical system
5.0 kW
starting point
Annual benefit
£831
before battery costs
Payback estimate
9.8 years
panel-only baseline
Postcode verdict
Roof-size upside
local model
Local context

Why SA15 differs

South-facing yield is about 3.8% above the South Wales median.

The starting system size is close to the regional typical size at 5.0 kW.

Local housing mix looks suitable for a postcode-level estimate, but your actual roof still matters more than the area average.

Battery payback depends heavily on evening use, export tariff and whether the installer has assumed optimistic self-consumption.

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
9.8 years
After this, it's pure profit
Upfront Cost
£8,139
What you pay to get started
Annual Benefit
£831
What you save every year
Profit Over 25 Years
£12,644
After paying itself off, you're this much ahead

Ready to Get Started?

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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.

Before you sign

What to challenge in solar quotes for SA15

Use the calculator above as a baseline, then ask installers to explain where their quote differs from the local assumptions.

If the proposed system is much larger than 5.0 kW, ask why it fits your roof and usage.

Compare payback with and without a battery before accepting a bundled quote.

Check which Smart Export Guarantee tariff is assumed. The calculator baseline uses 10p/kWh.

Confirm who handles MCS certification and DNO/G98/G99 paperwork before comparing finance or warranties.

Compare quotes Check MCS DNO, G98 and G99
New quote check

Want a quote sanity check for SA15?

Share the first part of your postcode and a few basics. We’ll help you check whether system size, battery, export and paperwork assumptions look sensible before you commit to installer conversations.

This is a practical sanity-check request, not an instant quote promise. The Blue Ape quote route above remains available if you already want installer introductions.

Request a quote sanity check →

Insights for SA15

Figures below are tailored to SA15 — click through for full league tables.

Big-Roof Britain Rank #1000 of 2182
5.1 kWp (UK avg 5.1 kWp)
~11 panels (≈430 W)
Solar Payback Index Rank #701 of 2996
9.8 years (UK avg 10.8 years)
~£832 /yr • £8,139 upfront
Standing-Charge Drag Rank #1502 of 2996
25.4% (UK avg 26.6%) drag on savings
£211 fixed • ~£832 /yr value
Aspect Penalty View ranking →
East −20.1% West −21.4%
Typical output loss versus a south-facing roof (lower is better)
Compare areas

Compare SA15 with nearby and similar areas

Nearby postcode areas in South Wales

SA14 (Carmarthenshire)
≈4.1 km away
Local sunshine: ~948 kWh/kWp · -6% vs SA15
SA16 (Carmarthenshire)
≈6.2 km away
Local sunshine: ~1,012 kWh/kWp · +1% vs SA15
SA4 (Swansea)
≈8.6 km away
Local sunshine: ~961 kWh/kWp · -4% vs SA15
SA17 (Carmarthenshire)
≈11.3 km away
Local sunshine: ~985 kWh/kWp · -2% vs SA15
SA2 (Swansea)
≈13.8 km away
Local sunshine: ~988 kWh/kWp · -2% vs SA15
SA5 (Swansea)
≈14.1 km away
Local sunshine: ~989 kWh/kWp · -2% vs SA15

Similar solar-yield areas

SE7 (Greenwich)
~1,006 kWh/kWp · -0% vs SA15
RH8 (Tandridge)
~1,006 kWh/kWp · +0% vs SA15
SE10 (Greenwich)
~1,006 kWh/kWp · +0% vs SA15

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 1006 kWh/kW — 37 above the regional median (968).

Read the full story

A typical roof here lands around 5.0 kW, with most eligible homes comfortably fitting within 3–6 kW. Each kilowatt of panels produces roughly 1006 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)
1006 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: £831, Upfront: £8,139, Break-even: 9.8 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2011 kWh 805 kWh 1207 kWh £212 £121 £333 £3,256 9.8 yrs £3,395
3 kW 3017 kWh 1207 kWh 1810 kWh £318 £181 £499 £4,883 9.8 yrs £5,092
4 kW 4023 kWh 1609 kWh 2414 kWh £424 £241 £665 £6,511 9.8 yrs £6,790
5 kW 5028 kWh 2011 kWh 3017 kWh £530 £302 £831 £8,139 9.8 yrs £8,487
6 kW 6034 kWh 2414 kWh 3621 kWh £636 £362 £998 £9,767 9.8 yrs £10,185
7 kW 7040 kWh 2816 kWh 4224 kWh £741 £422 £1,164 £11,394 9.8 yrs £11,882
8 kW 8046 kWh 3218 kWh 4827 kWh £847 £483 £1,330 £13,022 9.8 yrs £13,580

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: £996, Upfront: £10,239, Break-even: 10.3 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2011 kWh 1207 kWh 805 kWh £318 £80 £398 £5,356 13.4 yrs £2,609
3 kW 3017 kWh 1810 kWh 1207 kWh £477 £121 £597 £6,983 11.7 yrs £4,963
4 kW 4023 kWh 2414 kWh 1609 kWh £636 £161 £796 £8,611 10.8 yrs £7,318
5 kW 5028 kWh 3017 kWh 2011 kWh £794 £201 £996 £10,239 10.3 yrs £9,672
6 kW 6034 kWh 3621 kWh 2414 kWh £953 £241 £1,195 £11,867 9.9 yrs £12,026
7 kW 7040 kWh 4224 kWh 2816 kWh £1,112 £282 £1,394 £13,494 9.7 yrs £14,381
8 kW 8046 kWh 4827 kWh 3218 kWh £1,271 £322 £1,593 £15,122 9.5 yrs £16,735

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: £1,078, Upfront: £11,639, Break-even: 10.8 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2011 kWh 1408 kWh 603 kWh £371 £60 £431 £6,756 15.7 yrs £1,866
3 kW 3017 kWh 2112 kWh 905 kWh £556 £91 £647 £8,383 13.0 yrs £4,549
4 kW 4023 kWh 2816 kWh 1207 kWh £741 £121 £862 £10,011 11.6 yrs £7,231
5 kW 5028 kWh 3520 kWh 1509 kWh £927 £151 £1,078 £11,639 10.8 yrs £9,914
6 kW 6034 kWh 4224 kWh 1810 kWh £1,112 £181 £1,293 £13,267 10.3 yrs £12,597
7 kW 7040 kWh 4928 kWh 2112 kWh £1,298 £211 £1,509 £14,894 9.9 yrs £15,280
8 kW 8046 kWh 5632 kWh 2414 kWh £1,483 £241 £1,724 £16,522 9.6 yrs £17,963

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: £1,102, Upfront: £13,389, Break-even: 12.1 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2011 kWh 1468 kWh 543 kWh £387 £54 £441 £8,506 19.3 yrs £313
3 kW 3017 kWh 2202 kWh 815 kWh £580 £81 £661 £10,133 15.3 yrs £3,094
4 kW 4023 kWh 2937 kWh 1086 kWh £773 £109 £882 £11,761 13.3 yrs £5,876
5 kW 5028 kWh 3671 kWh 1358 kWh £967 £136 £1,102 £13,389 12.1 yrs £8,657
6 kW 6034 kWh 4405 kWh 1629 kWh £1,160 £163 £1,323 £15,017 11.4 yrs £11,438
7 kW 7040 kWh 5139 kWh 1901 kWh £1,353 £190 £1,543 £16,644 10.8 yrs £14,220
8 kW 8046 kWh 5873 kWh 2172 kWh £1,546 £217 £1,764 £18,272 10.4 yrs £17,001

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: £1,119, Upfront: £15,139, Break-even: 13.5 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2011 kWh 1509 kWh 503 kWh £397 £50 £447 £10,256 22.9 yrs £-1,306
3 kW 3017 kWh 2263 kWh 754 kWh £596 £75 £671 £11,883 17.7 yrs £1,541
4 kW 4023 kWh 3017 kWh 1006 kWh £794 £101 £895 £13,511 15.1 yrs £4,388
5 kW 5028 kWh 3771 kWh 1257 kWh £993 £126 £1,119 £15,139 13.5 yrs £7,236
6 kW 6034 kWh 4526 kWh 1509 kWh £1,192 £151 £1,342 £16,767 12.5 yrs £10,083
7 kW 7040 kWh 5280 kWh 1760 kWh £1,390 £176 £1,566 £18,394 11.7 yrs £12,930
8 kW 8046 kWh 6034 kWh 2011 kWh £1,589 £201 £1,790 £20,022 11.2 yrs £15,777

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: £1,135, Upfront: £17,589, Break-even: 15.5 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2011 kWh 1549 kWh 463 kWh £408 £46 £454 £12,706 28.0 yrs £-3,624
3 kW 3017 kWh 2323 kWh 694 kWh £612 £69 £681 £14,333 21.0 yrs £-712
4 kW 4023 kWh 3098 kWh 925 kWh £816 £93 £908 £15,961 17.6 yrs £2,201
5 kW 5028 kWh 3872 kWh 1157 kWh £1,019 £116 £1,135 £17,589 15.5 yrs £5,114
6 kW 6034 kWh 4646 kWh 1388 kWh £1,223 £139 £1,362 £19,217 14.1 yrs £8,027
7 kW 7040 kWh 5421 kWh 1619 kWh £1,427 £162 £1,589 £20,844 13.1 yrs £10,940
8 kW 8046 kWh 6195 kWh 1850 kWh £1,631 £185 £1,816 £22,472 12.4 yrs £13,852

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.

Seasonal solar output in SA15

Monthly generation per kilowatt of solar panels

kWh 37 Jan 54 Feb 88 Mar 118 Apr 126 May 124 Jun 120 Jul 108 Aug 92 Sep 63 Oct 43 Nov 32 Dec
Best month Worst month Winter (Dec–Feb) Other months

Winter output: 49.1% 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 41 kWh per month; the average month produces around 84 kWh. So a typical 4 kW home system would generate roughly 165 kWh in winter, or 335 kWh in an average month.

Your Area at a Glance

Your Electricity Rate
26.33p/kWh
Daily Fixed Charge
57.84p/day
Local Sunshine
1006kWh/kW
A 1 kW system generates ~1006 kWh per year. A typical home uses ~2,700 kWh per year.
Typical System Size
5.0kW
For houses & bungalows in this area

Local Property Data

Property Types

Houses: 77% • Flats: 15% • Bungalows: 7% Based on 10,399 properties

Coverage

Carmarthenshire (100%)

Areas Covered

Tyisha, Glanymor, Bigyn, Lliedi, Hengoed, Glyn, Pontyberem, Elli + 4 more

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.