Independent solar numbers for your postcode using official UK data
Home Regions Guides Compare quotes Solar assistant
Insights
Big Roof Britain Solar Payback Index Standing Charge Drag Roof Direction Penalty Winter Solar Reality Seasonal Solar Output

Solar panel cost in Monmouthshire (NP15)

See realistic solar installation costs, savings and payback for NP15 (Monmouthshire) 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
10.2 years
After this, it's pure profit
Upfront Cost
£9,767
What you pay to get started
Annual Benefit
£957
What you save every year
Profit Over 25 Years
£14,148
After paying itself off, you're this much ahead

Ready to Get Started?

Get your free quote from Blue Ape Renewables. They'll connect you with MCS-certified installers in your area and handle all the paperwork.

Get Solar Quote →
4.8★ Trustpilot • Octopus Energy trusted partner • MCS certified • No obligation
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 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 964 kWh/kW — 4 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 964 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)
964 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: £797, Upfront: £8,139, Break-even: 10.2 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1929 kWh 771 kWh 1157 kWh £203 £116 £319 £3,256 10.2 yrs £3,122
3 kW 2893 kWh 1157 kWh 1736 kWh £305 £174 £478 £4,883 10.2 yrs £4,682
4 kW 3857 kWh 1543 kWh 2314 kWh £406 £231 £638 £6,511 10.2 yrs £6,243
5 kW 4822 kWh 1929 kWh 2893 kWh £508 £289 £797 £8,139 10.2 yrs £7,804
6 kW 5786 kWh 2314 kWh 3472 kWh £609 £347 £957 £9,767 10.2 yrs £9,365
7 kW 6751 kWh 2700 kWh 4050 kWh £711 £405 £1,116 £11,394 10.2 yrs £10,926
8 kW 7715 kWh 3086 kWh 4629 kWh £813 £463 £1,275 £13,022 10.2 yrs £12,487

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: £955, Upfront: £10,239, Break-even: 10.7 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1929 kWh 1157 kWh 771 kWh £305 £77 £382 £5,356 14.0 yrs £2,282
3 kW 2893 kWh 1736 kWh 1157 kWh £457 £116 £573 £6,983 12.2 yrs £4,472
4 kW 3857 kWh 2314 kWh 1543 kWh £609 £154 £764 £8,611 11.3 yrs £6,663
5 kW 4822 kWh 2893 kWh 1929 kWh £762 £193 £955 £10,239 10.7 yrs £8,854
6 kW 5786 kWh 3472 kWh 2314 kWh £914 £231 £1,146 £11,867 10.4 yrs £11,045
7 kW 6751 kWh 4050 kWh 2700 kWh £1,066 £270 £1,336 £13,494 10.1 yrs £13,235
8 kW 7715 kWh 4629 kWh 3086 kWh £1,219 £309 £1,527 £15,122 9.9 yrs £15,426

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: £1,033, Upfront: £11,639, 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 1929 kWh 1350 kWh 579 kWh £355 £58 £413 £6,756 16.3 yrs £1,511
3 kW 2893 kWh 2025 kWh 868 kWh £533 £87 £620 £8,383 13.5 yrs £4,017
4 kW 3857 kWh 2700 kWh 1157 kWh £711 £116 £827 £10,011 12.1 yrs £6,523
5 kW 4822 kWh 3375 kWh 1447 kWh £889 £145 £1,033 £11,639 11.3 yrs £9,029
6 kW 5786 kWh 4050 kWh 1736 kWh £1,066 £174 £1,240 £13,267 10.7 yrs £11,534
7 kW 6751 kWh 4725 kWh 2025 kWh £1,244 £203 £1,447 £14,894 10.3 yrs £14,040
8 kW 7715 kWh 5400 kWh 2314 kWh £1,422 £231 £1,653 £16,522 10.0 yrs £16,546

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: £1,057, Upfront: £13,389, Break-even: 12.7 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1929 kWh 1408 kWh 521 kWh £371 £52 £423 £8,506 20.1 yrs £-50
3 kW 2893 kWh 2112 kWh 781 kWh £556 £78 £634 £10,133 16.0 yrs £2,551
4 kW 3857 kWh 2816 kWh 1042 kWh £741 £104 £846 £11,761 13.9 yrs £5,151
5 kW 4822 kWh 3520 kWh 1302 kWh £927 £130 £1,057 £13,389 12.7 yrs £7,751
6 kW 5786 kWh 4224 kWh 1562 kWh £1,112 £156 £1,268 £15,017 11.8 yrs £10,351
7 kW 6751 kWh 4928 kWh 1823 kWh £1,298 £182 £1,480 £16,644 11.2 yrs £12,951
8 kW 7715 kWh 5632 kWh 2083 kWh £1,483 £208 £1,691 £18,272 10.8 yrs £15,552

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: £1,073, Upfront: £15,139, Break-even: 14.1 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1929 kWh 1447 kWh 482 kWh £381 £48 £429 £10,256 23.9 yrs £-1,674
3 kW 2893 kWh 2170 kWh 723 kWh £571 £72 £644 £11,883 18.5 yrs £990
4 kW 3857 kWh 2893 kWh 964 kWh £762 £96 £858 £13,511 15.7 yrs £3,653
5 kW 4822 kWh 3616 kWh 1205 kWh £952 £121 £1,073 £15,139 14.1 yrs £6,316
6 kW 5786 kWh 4340 kWh 1447 kWh £1,143 £145 £1,287 £16,767 13.0 yrs £8,979
7 kW 6751 kWh 5063 kWh 1688 kWh £1,333 £169 £1,502 £18,394 12.2 yrs £11,642
8 kW 7715 kWh 5786 kWh 1929 kWh £1,524 £193 £1,716 £20,022 11.7 yrs £14,306

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: £1,088, Upfront: £17,589, Break-even: 16.2 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1929 kWh 1485 kWh 444 kWh £391 £44 £435 £12,706 29.2 yrs £-3,998
3 kW 2893 kWh 2228 kWh 665 kWh £587 £67 £653 £14,333 21.9 yrs £-1,271
4 kW 3857 kWh 2970 kWh 887 kWh £782 £89 £871 £15,961 18.3 yrs £1,455
5 kW 4822 kWh 3713 kWh 1109 kWh £978 £111 £1,088 £17,589 16.2 yrs £4,181
6 kW 5786 kWh 4455 kWh 1331 kWh £1,173 £133 £1,306 £19,217 14.7 yrs £6,907
7 kW 6751 kWh 5198 kWh 1553 kWh £1,369 £155 £1,524 £20,844 13.7 yrs £9,633
8 kW 7715 kWh 5941 kWh 1774 kWh £1,564 £177 £1,742 £22,472 12.9 yrs £12,360

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 Monmouthshire

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.

Compare solar quotes before you sign

Check what MCS certification means

Understand DNO, G98 and G99 export limits

New quote check

Want a quote sanity check for NP15?

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 NP15

Figures below are tailored to NP15 — click through for full league tables.

Big-Roof Britain Rank #154 of 2182
6.3 kWp (UK avg 5.1 kWp)
~13 panels (≈430 W)
Solar Payback Index Rank #1315 of 2996
10.2 years (UK avg 10.8 years)
~£956 /yr • £9,767 upfront
Standing-Charge Drag Rank #918 of 2996
22.1% (UK avg 26.6%) drag on savings
£211 fixed • ~£956 /yr value
Aspect Penalty View ranking →
East −19.7% West −19.6%
Typical output loss versus a south-facing roof (lower is better)

Seasonal solar output in NP15

Monthly generation per kilowatt of solar panels

kWh 35 Jan 50 Feb 82 Mar 110 Apr 120 May 119 Jun 120 Jul 104 Aug 90 Sep 62 Oct 41 Nov 30 Dec
Best month Worst month Winter (Dec–Feb) Other months

Winter output: 48.0% 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 39 kWh per month; the average month produces around 80 kWh. So a typical 4 kW home system would generate roughly 154 kWh in winter, or 321 kWh in an average month.

Your Area at a Glance

Your Electricity Rate
26.33p/kWh
Daily Fixed Charge
57.84p/day
Local Sunshine
964kWh/kW
A 1 kW system generates ~964 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: 75% • Flats: 12% • Bungalows: 13% Based on 1,856 properties

Coverage

Monmouthshire (100%)

Areas Covered

Llanbadoc and Usk, Raglan, Gobion Fawr, Llangybi Fawr, Devauden, Llantilio Crossenny, Mitchel Troy and Trellech United, Shirenewton + 1 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.

Compare nearby areas

Nearby in South Wales

NP4 (Torfaen)
≈9.6 km away
Local sunshine: ~966 kWh/kWp · +0% vs NP15
NP44 (Torfaen)
≈10.5 km away
Local sunshine: ~971 kWh/kWp · +1% vs NP15
NP18 (Newport)
≈11.4 km away
Local sunshine: ~997 kWh/kWp · +3% vs NP15
NP5 (Monmouthshire)
≈12.7 km away
Local sunshine: ~964 kWh/kWp · -0% vs NP15
NP19 (Newport)
≈14.1 km away
Local sunshine: ~1,000 kWh/kWp · +4% vs NP15
NP6 (Monmouthshire)
≈14.2 km away
Local sunshine: ~996 kWh/kWp · +3% vs NP15

Similar sunshine across the UK

EX37 (North Devon)
~964 kWh/kWp · -0% vs NP15
GL51 (Cheltenham)
~964 kWh/kWp · -0% vs NP15
PL34 (Cornwall)
~964 kWh/kWp · -0% vs NP15