Solar panel cost in Gwynedd (LL41)

See realistic solar installation costs, savings and payback for LL41 (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
£8,138
What you pay to get started
Annual Benefit
£510
What you save every year
Profit Over 25 Years
£4,603
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

Read the full story

A typical roof here lands around 4.0 kW, with most eligible homes comfortably fitting within 3–6 kW. Each kilowatt of panels produces roughly 808 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)
808 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: £637, 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 1616 kWh 646 kWh 969 kWh £158 £97 £255 £4,069 16.0 yrs £1,027
3 kW 2423 kWh 969 kWh 1454 kWh £237 £145 £382 £6,104 16.0 yrs £1,541
4 kW 3231 kWh 1293 kWh 1939 kWh £316 £194 £510 £8,138 16.0 yrs £2,055
5 kW 4039 kWh 1616 kWh 2423 kWh £395 £242 £637 £10,173 16.0 yrs £2,568
6 kW 4847 kWh 1939 kWh 2908 kWh £474 £291 £764 £12,207 16.0 yrs £3,082
7 kW 5655 kWh 2262 kWh 3393 kWh £553 £339 £892 £14,242 16.0 yrs £3,596
8 kW 6463 kWh 2585 kWh 3878 kWh £632 £388 £1,019 £16,276 16.0 yrs £4,109

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: £754, 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 1616 kWh 969 kWh 646 kWh £237 £65 £301 £6,169 20.5 yrs £-140
3 kW 2423 kWh 1454 kWh 969 kWh £355 £97 £452 £8,204 18.1 yrs £840
4 kW 3231 kWh 1939 kWh 1293 kWh £474 £129 £603 £10,238 17.0 yrs £1,820
5 kW 4039 kWh 2423 kWh 1616 kWh £592 £162 £754 £12,273 16.3 yrs £2,800
6 kW 4847 kWh 2908 kWh 1939 kWh £710 £194 £904 £14,307 15.8 yrs £3,780
7 kW 5655 kWh 3393 kWh 2262 kWh £829 £226 £1,055 £16,342 15.5 yrs £4,760
8 kW 6463 kWh 3878 kWh 2585 kWh £947 £259 £1,206 £18,376 15.2 yrs £5,740

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: £812, Upfront: £13,673, Break-even: 16.8 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1616 kWh 1131 kWh 485 kWh £276 £48 £325 £7,569 23.3 yrs £-1,074
3 kW 2423 kWh 1696 kWh 727 kWh £414 £73 £487 £9,604 19.7 yrs £139
4 kW 3231 kWh 2262 kWh 969 kWh £553 £97 £650 £11,638 17.9 yrs £1,352
5 kW 4039 kWh 2827 kWh 1212 kWh £691 £121 £812 £13,673 16.8 yrs £2,565
6 kW 4847 kWh 3393 kWh 1454 kWh £829 £145 £974 £15,707 16.1 yrs £3,779
7 kW 5655 kWh 3958 kWh 1696 kWh £967 £170 £1,137 £17,742 15.6 yrs £4,992
8 kW 6463 kWh 4524 kWh 1939 kWh £1,105 £194 £1,299 £19,776 15.2 yrs £6,205

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: £829, Upfront: £15,423, Break-even: 18.6 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1616 kWh 1179 kWh 436 kWh £288 £44 £332 £9,319 28.1 yrs £-2,684
3 kW 2423 kWh 1769 kWh 654 kWh £432 £65 £498 £11,354 22.8 yrs £-1,401
4 kW 3231 kWh 2359 kWh 872 kWh £576 £87 £664 £13,388 20.2 yrs £-118
5 kW 4039 kWh 2949 kWh 1091 kWh £720 £109 £829 £15,423 18.6 yrs £1,165
6 kW 4847 kWh 3538 kWh 1309 kWh £864 £131 £995 £17,457 17.5 yrs £2,448
7 kW 5655 kWh 4128 kWh 1527 kWh £1,008 £153 £1,161 £19,492 16.8 yrs £3,731
8 kW 6463 kWh 4718 kWh 1745 kWh £1,153 £174 £1,327 £21,526 16.2 yrs £5,014

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: £841, Upfront: £17,173, Break-even: 20.4 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1616 kWh 1212 kWh 404 kWh £296 £40 £336 £11,069 32.9 yrs £-4,341
3 kW 2423 kWh 1818 kWh 606 kWh £444 £61 £505 £13,104 26.0 yrs £-3,011
4 kW 3231 kWh 2423 kWh 808 kWh £592 £81 £673 £15,138 22.5 yrs £-1,681
5 kW 4039 kWh 3029 kWh 1010 kWh £740 £101 £841 £17,173 20.4 yrs £-352
6 kW 4847 kWh 3635 kWh 1212 kWh £888 £121 £1,009 £19,207 19.0 yrs £978
7 kW 5655 kWh 4241 kWh 1414 kWh £1,036 £141 £1,177 £21,242 18.0 yrs £2,308
8 kW 6463 kWh 4847 kWh 1616 kWh £1,184 £162 £1,346 £23,276 17.3 yrs £3,637

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: £853, Upfront: £19,623, Break-even: 23.0 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1616 kWh 1244 kWh 372 kWh £304 £37 £341 £13,519 39.6 yrs £-6,697
3 kW 2423 kWh 1866 kWh 557 kWh £456 £56 £512 £15,554 30.4 yrs £-5,321
4 kW 3231 kWh 2488 kWh 743 kWh £608 £74 £682 £17,588 25.8 yrs £-3,945
5 kW 4039 kWh 3110 kWh 929 kWh £760 £93 £853 £19,623 23.0 yrs £-2,569
6 kW 4847 kWh 3732 kWh 1115 kWh £912 £111 £1,023 £21,657 21.2 yrs £-1,192
7 kW 5655 kWh 4354 kWh 1301 kWh £1,064 £130 £1,194 £23,692 19.8 yrs £184
8 kW 6463 kWh 4976 kWh 1486 kWh £1,216 £149 £1,364 £25,726 18.9 yrs £1,560

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.

Seasonal solar output in LL41

Monthly generation per kilowatt of solar panels

kWh 23 Jan 38 Feb 72 Mar 100 Apr 108 May 105 Jun 102 Jul 88 Aug 74 Sep 48 Oct 29 Nov 20 Dec
Best month Worst month Winter (Dec–Feb) Other months

Winter output: 40.3% 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 27 kWh per month; the average month produces around 67 kWh. So a typical 4 kW home system would generate roughly 109 kWh in winter, or 269 kWh in an average month.

Your Area at a Glance

Your Electricity Rate
24.43p/kWh
Daily Fixed Charge
69.98p/day
Local Sunshine
808kWh/kW
A 1 kW system generates ~808 kWh per year. A typical home uses ~2,700 kWh per year.
Typical System Size
4.0kW
For houses & bungalows in this area

Local Property Data

Property Types

Houses: 86% • Flats: 6% • Bungalows: 6% Based on 1,796 properties

Coverage

Gwynedd (100%)

Areas Covered

Bowydd a'r Rhiw, Diffwys a Maenofferen, Trawsfynydd, Teigl, Harlech a Llanbedr

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.