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Solar panel cost in Gwynedd (LL40)

See realistic solar installation costs, savings and payback for LL40 (Gwynedd) 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
16.0 years
After this, it's pure profit
Upfront Cost
£12,207
What you pay to get started
Annual Benefit
£762
What you save every year
Profit Over 25 Years
£6,844
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 North Wales and Mersey, the current unit rate is 24.43p/kWh with a 69.98p/day standing charge. Your postcode’s south-facing sunshine yield is 805 kWh/kW — 125 below the regional median (930).

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 805 kWh per year on a south-facing roof. We value self-used electricity at 24.4p and exported surplus at a baseline 10p via SEG. Use the calculator above for your exact tariff.

Unit rate
24.4p/kWh
Standing charge
70.0p/day
Sunshine yield (south)
805 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: £635, Upfront: £10,173, Break-even: 16.0 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1611 kWh 644 kWh 966 kWh £157 £97 £254 £4,069 16.0 yrs £1,011
3 kW 2416 kWh 966 kWh 1450 kWh £236 £145 £381 £6,104 16.0 yrs £1,517
4 kW 3221 kWh 1288 kWh 1933 kWh £315 £193 £508 £8,138 16.0 yrs £2,023
5 kW 4026 kWh 1611 kWh 2416 kWh £393 £242 £635 £10,173 16.0 yrs £2,528
6 kW 4832 kWh 1933 kWh 2899 kWh £472 £290 £762 £12,207 16.0 yrs £3,034
7 kW 5637 kWh 2255 kWh 3382 kWh £551 £338 £889 £14,242 16.0 yrs £3,540
8 kW 6442 kWh 2577 kWh 3865 kWh £630 £387 £1,016 £16,276 16.0 yrs £4,046

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: £751, Upfront: £12,273, Break-even: 16.3 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1611 kWh 966 kWh 644 kWh £236 £64 £301 £6,169 20.5 yrs £-159
3 kW 2416 kWh 1450 kWh 966 kWh £354 £97 £451 £8,204 18.2 yrs £812
4 kW 3221 kWh 1933 kWh 1288 kWh £472 £129 £601 £10,238 17.0 yrs £1,782
5 kW 4026 kWh 2416 kWh 1611 kWh £590 £161 £751 £12,273 16.3 yrs £2,753
6 kW 4832 kWh 2899 kWh 1933 kWh £708 £193 £902 £14,307 15.9 yrs £3,723
7 kW 5637 kWh 3382 kWh 2255 kWh £826 £225 £1,052 £16,342 15.5 yrs £4,694
8 kW 6442 kWh 3865 kWh 2577 kWh £944 £258 £1,202 £18,376 15.3 yrs £5,664

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: £809, Upfront: £13,673, Break-even: 16.9 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1611 kWh 1127 kWh 483 kWh £275 £48 £324 £7,569 23.4 yrs £-1,094
3 kW 2416 kWh 1691 kWh 725 kWh £413 £72 £486 £9,604 19.8 yrs £109
4 kW 3221 kWh 2255 kWh 966 kWh £551 £97 £647 £11,638 18.0 yrs £1,312
5 kW 4026 kWh 2819 kWh 1208 kWh £689 £121 £809 £13,673 16.9 yrs £2,515
6 kW 4832 kWh 3382 kWh 1450 kWh £826 £145 £971 £15,707 16.2 yrs £3,718
7 kW 5637 kWh 3946 kWh 1691 kWh £964 £169 £1,133 £17,742 15.7 yrs £4,920
8 kW 6442 kWh 4510 kWh 1933 kWh £1,102 £193 £1,295 £19,776 15.3 yrs £6,123

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: £827, Upfront: £15,423, Break-even: 18.7 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1611 kWh 1176 kWh 435 kWh £287 £43 £331 £9,319 28.2 yrs £-2,705
3 kW 2416 kWh 1764 kWh 652 kWh £431 £65 £496 £11,354 22.9 yrs £-1,432
4 kW 3221 kWh 2351 kWh 870 kWh £574 £87 £661 £13,388 20.2 yrs £-159
5 kW 4026 kWh 2939 kWh 1087 kWh £718 £109 £827 £15,423 18.7 yrs £1,113
6 kW 4832 kWh 3527 kWh 1305 kWh £862 £130 £992 £17,457 17.6 yrs £2,386
7 kW 5637 kWh 4115 kWh 1522 kWh £1,005 £152 £1,158 £19,492 16.8 yrs £3,658
8 kW 6442 kWh 4703 kWh 1739 kWh £1,149 £174 £1,323 £21,526 16.3 yrs £4,931

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: £838, Upfront: £17,173, Break-even: 20.5 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1611 kWh 1208 kWh 403 kWh £295 £40 £335 £11,069 33.0 yrs £-4,362
3 kW 2416 kWh 1812 kWh 604 kWh £443 £60 £503 £13,104 26.0 yrs £-3,043
4 kW 3221 kWh 2416 kWh 805 kWh £590 £81 £671 £15,138 22.6 yrs £-1,724
5 kW 4026 kWh 3020 kWh 1007 kWh £738 £101 £838 £17,173 20.5 yrs £-404
6 kW 4832 kWh 3624 kWh 1208 kWh £885 £121 £1,006 £19,207 19.1 yrs £915
7 kW 5637 kWh 4228 kWh 1409 kWh £1,033 £141 £1,174 £21,242 18.1 yrs £2,234
8 kW 6442 kWh 4832 kWh 1611 kWh £1,180 £161 £1,341 £23,276 17.4 yrs £3,553

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: £850, Upfront: £19,623, Break-even: 23.1 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1611 kWh 1240 kWh 370 kWh £303 £37 £340 £13,519 39.8 yrs £-6,719
3 kW 2416 kWh 1860 kWh 556 kWh £454 £56 £510 £15,554 30.5 yrs £-5,353
4 kW 3221 kWh 2480 kWh 741 kWh £606 £74 £680 £17,588 25.9 yrs £-3,988
5 kW 4026 kWh 3100 kWh 926 kWh £757 £93 £850 £19,623 23.1 yrs £-2,622
6 kW 4832 kWh 3720 kWh 1111 kWh £909 £111 £1,020 £21,657 21.2 yrs £-1,256
7 kW 5637 kWh 4341 kWh 1297 kWh £1,060 £130 £1,190 £23,692 19.9 yrs £109
8 kW 6442 kWh 4961 kWh 1482 kWh £1,212 £148 £1,360 £25,726 18.9 yrs £1,475

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 LL40

Figures below are tailored to LL40 — click through for full league tables.

Big-Roof Britain Rank #520 of 2182
5.6 kWp (UK avg 5.1 kWp)
~12 panels (≈430 W)
Solar Payback Index Rank #2751 of 2997
14.3 years (UK avg 12.6 years)
~£852 /yr • £12,207 upfront
Standing-Charge Drag Rank #2408 of 2997
30.4% (UK avg 24.6%) drag on savings
£259 fixed • ~£852 /yr value
Aspect Penalty View ranking →
East −16.1% West −18.5%
Typical output loss versus a south-facing roof (lower is better)

Seasonal solar output in LL40

Monthly generation per kilowatt of solar panels

kWh 22 Jan 37 Feb 71 Mar 99 Apr 109 May 106 Jun 103 Jul 90 Aug 74 Sep 47 Oct 29 Nov 18 Dec
Best month Worst month Winter (Dec–Feb) Other months

Winter output: 38.3% 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 26 kWh per month; the average month produces around 67 kWh. So a typical 4 kW home system would generate roughly 103 kWh in winter, or 268 kWh in an average month.

Your Area at a Glance

Your Electricity Rate
24.43p/kWh
Daily Fixed Charge
69.98p/day
Local Sunshine
805kWh/kW
A 1 kW system generates ~805 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: 68% • Flats: 14% • Bungalows: 16% Based on 1,190 properties

Coverage

Gwynedd (100%)

Areas Covered

Brithdir and Llanfachreth/Ganllwyd/Llanelltyd, Gogledd Dolgellau, De Dolgellau, Arthog a Llangelynnin, Abermaw, Llanuwchllyn, Trawsfynydd

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 North Wales and Mersey

LL39 (Gwynedd)
≈9.3 km away
Local sunshine: ~825 kWh/kWp · +2% vs LL40
LL42 (Gwynedd)
≈11.8 km away
Local sunshine: ~864 kWh/kWp · +7% vs LL40
LL38 (Gwynedd)
≈12.4 km away
Local sunshine: ~846 kWh/kWp · +5% vs LL40
LL43 (Gwynedd)
≈14.4 km away
Local sunshine: ~875 kWh/kWp · +9% vs LL40
LL44 (Gwynedd)
≈15.2 km away
Local sunshine: ~875 kWh/kWp · +9% vs LL40
LL37 (Gwynedd)
≈16.0 km away
Local sunshine: ~878 kWh/kWp · +9% vs LL40

Similar sunshine across the UK

IV13 (Highland)
~805 kWh/kWp · -0% vs LL40
KW16 (Orkney Islands)
~806 kWh/kWp · +0% vs LL40
BT47 (Derry City and Strabane)
~806 kWh/kWp · +0% vs LL40