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Solar panel cost in Gwynedd (LL37)

See realistic solar installation costs, savings and payback for LL37 (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
10.9 years
After this, it's pure profit
Upfront Cost
£9,767
What you pay to get started
Annual Benefit
£899
What you save every year
Profit Over 25 Years
£12,701
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 North Wales and Mersey, the current unit rate is 27.66p/kWh with a 70.76p/day standing charge. Your postcode’s south-facing sunshine yield is 878 kWh/kW — 52 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 878 kWh per year on a south-facing roof. We value self-used electricity at 27.7p and exported surplus at a baseline 10p via SEG. Use the calculator above for your exact tariff.

Unit rate
27.7p/kWh
Standing charge
70.8p/day
Sunshine yield (south)
878 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: £749, Upfront: £8,139, 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 1756 kWh 702 kWh 1053 kWh £194 £105 £300 £3,256 10.9 yrs £2,736
3 kW 2633 kWh 1053 kWh 1580 kWh £291 £158 £449 £4,883 10.9 yrs £4,104
4 kW 3511 kWh 1404 kWh 2107 kWh £388 £211 £599 £6,511 10.9 yrs £5,472
5 kW 4389 kWh 1756 kWh 2633 kWh £486 £263 £749 £8,139 10.9 yrs £6,840
6 kW 5267 kWh 2107 kWh 3160 kWh £583 £316 £899 £9,767 10.9 yrs £8,208
7 kW 6144 kWh 2458 kWh 3687 kWh £680 £369 £1,048 £11,394 10.9 yrs £9,575
8 kW 7022 kWh 2809 kWh 4213 kWh £777 £421 £1,198 £13,022 10.9 yrs £10,943

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: £904, Upfront: £10,239, Break-even: 11.3 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1756 kWh 1053 kWh 702 kWh £291 £70 £362 £5,356 14.8 yrs £1,876
3 kW 2633 kWh 1580 kWh 1053 kWh £437 £105 £542 £6,983 12.9 yrs £3,864
4 kW 3511 kWh 2107 kWh 1404 kWh £583 £140 £723 £8,611 11.9 yrs £5,852
5 kW 4389 kWh 2633 kWh 1756 kWh £728 £176 £904 £10,239 11.3 yrs £7,840
6 kW 5267 kWh 3160 kWh 2107 kWh £874 £211 £1,085 £11,867 10.9 yrs £9,828
7 kW 6144 kWh 3687 kWh 2458 kWh £1,020 £246 £1,266 £13,494 10.7 yrs £11,816
8 kW 7022 kWh 4213 kWh 2809 kWh £1,165 £281 £1,446 £15,122 10.5 yrs £13,804

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: £981, Upfront: £11,639, Break-even: 11.9 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1756 kWh 1229 kWh 527 kWh £340 £53 £393 £6,756 17.2 yrs £1,096
3 kW 2633 kWh 1843 kWh 790 kWh £510 £79 £589 £8,383 14.2 yrs £3,394
4 kW 3511 kWh 2458 kWh 1053 kWh £680 £105 £785 £10,011 12.8 yrs £5,692
5 kW 4389 kWh 3072 kWh 1317 kWh £850 £132 £981 £11,639 11.9 yrs £7,990
6 kW 5267 kWh 3687 kWh 1580 kWh £1,020 £158 £1,178 £13,267 11.3 yrs £10,288
7 kW 6144 kWh 4301 kWh 1843 kWh £1,190 £184 £1,374 £14,894 10.8 yrs £12,586
8 kW 7022 kWh 4916 kWh 2107 kWh £1,360 £211 £1,570 £16,522 10.5 yrs £14,884

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: £1,005, Upfront: £13,389, Break-even: 13.3 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1756 kWh 1282 kWh 474 kWh £354 £47 £402 £8,506 21.2 yrs £-468
3 kW 2633 kWh 1922 kWh 711 kWh £532 £71 £603 £10,133 16.8 yrs £1,923
4 kW 3511 kWh 2563 kWh 948 kWh £709 £95 £804 £11,761 14.6 yrs £4,314
5 kW 4389 kWh 3204 kWh 1185 kWh £886 £119 £1,005 £13,389 13.3 yrs £6,705
6 kW 5267 kWh 3845 kWh 1422 kWh £1,063 £142 £1,206 £15,017 12.5 yrs £9,096
7 kW 6144 kWh 4485 kWh 1659 kWh £1,241 £166 £1,407 £16,644 11.8 yrs £11,487
8 kW 7022 kWh 5126 kWh 1896 kWh £1,418 £190 £1,608 £18,272 11.4 yrs £13,878

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: £1,020, Upfront: £15,139, Break-even: 14.8 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1756 kWh 1317 kWh 439 kWh £364 £44 £408 £10,256 25.1 yrs £-2,094
3 kW 2633 kWh 1975 kWh 658 kWh £546 £66 £612 £11,883 19.4 yrs £359
4 kW 3511 kWh 2633 kWh 878 kWh £728 £88 £816 £13,511 16.6 yrs £2,812
5 kW 4389 kWh 3292 kWh 1097 kWh £910 £110 £1,020 £15,139 14.8 yrs £5,265
6 kW 5267 kWh 3950 kWh 1317 kWh £1,093 £132 £1,224 £16,767 13.7 yrs £7,718
7 kW 6144 kWh 4608 kWh 1536 kWh £1,275 £154 £1,428 £18,394 12.9 yrs £10,171
8 kW 7022 kWh 5267 kWh 1756 kWh £1,457 £176 £1,632 £20,022 12.3 yrs £12,624

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: £1,036, Upfront: £17,589, Break-even: 17.0 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1756 kWh 1352 kWh 404 kWh £374 £40 £414 £12,706 30.7 yrs £-4,420
3 kW 2633 kWh 2028 kWh 606 kWh £561 £61 £621 £14,333 23.1 yrs £-1,905
4 kW 3511 kWh 2704 kWh 808 kWh £748 £81 £829 £15,961 19.3 yrs £610
5 kW 4389 kWh 3379 kWh 1009 kWh £935 £101 £1,036 £17,589 17.0 yrs £3,125
6 kW 5267 kWh 4055 kWh 1211 kWh £1,122 £121 £1,243 £19,217 15.5 yrs £5,640
7 kW 6144 kWh 4731 kWh 1413 kWh £1,309 £141 £1,450 £20,844 14.4 yrs £8,155
8 kW 7022 kWh 5407 kWh 1615 kWh £1,496 £162 £1,657 £22,472 13.6 yrs £10,670

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 Gwynedd

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 LL37

Figures below are tailored to LL37 — click through for full league tables.

Big-Roof Britain Rank #49 of 2182
7.1 kWp (UK avg 5.1 kWp)
~15 panels (≈430 W)
Solar Payback Index Rank #1892 of 2996
10.9 years (UK avg 10.8 years)
~£899 /yr • £9,767 upfront
Standing-Charge Drag Rank #2007 of 2996
28.7% (UK avg 26.6%) drag on savings
£258 fixed • ~£899 /yr value
Aspect Penalty View ranking →
East −18.2% West −21.7%
Typical output loss versus a south-facing roof (lower is better)

Seasonal solar output in LL37

Monthly generation per kilowatt of solar panels

kWh 28 Jan 45 Feb 78 Mar 108 Apr 117 May 113 Jun 109 Jul 96 Aug 78 Sep 52 Oct 32 Nov 22 Dec
Best month Worst month Winter (Dec–Feb) Other months

Winter output: 43.2% 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 32 kWh per month; the average month produces around 73 kWh. So a typical 4 kW home system would generate roughly 127 kWh in winter, or 293 kWh in an average month.

Your Area at a Glance

Your Electricity Rate
27.66p/kWh
Daily Fixed Charge
70.76p/day
Local Sunshine
878kWh/kW
A 1 kW system generates ~878 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: 70% • Flats: 3% • Bungalows: 26% Based on 206 properties

Coverage

Gwynedd (100%)

Areas Covered

Arthog a Llangelynnin, De Dolgellau

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 North Wales and Mersey

LL38 (Gwynedd)
≈4.0 km away
Local sunshine: ~846 kWh/kWp · -4% vs LL37
LL42 (Gwynedd)
≈6.7 km away
Local sunshine: ~864 kWh/kWp · -2% vs LL37
LL39 (Gwynedd)
≈6.9 km away
Local sunshine: ~825 kWh/kWp · -6% vs LL37
LL36 (Gwynedd)
≈8.7 km away
Local sunshine: ~940 kWh/kWp · +7% vs LL37
LL43 (Gwynedd)
≈12.1 km away
Local sunshine: ~875 kWh/kWp · -0% vs LL37
LL44 (Gwynedd)
≈13.7 km away
Local sunshine: ~875 kWh/kWp · -0% vs LL37

Similar sunshine across the UK

EH1 (City of Edinburgh)
~878 kWh/kWp · +0% vs LL37
KA23 (North Ayrshire)
~878 kWh/kWp · -0% vs LL37
BT68 (Mid Ulster)
~878 kWh/kWp · +0% vs LL37