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Solar panel cost in Southampton (SO18)

See realistic solar installation costs, savings and payback for SO18 (Southampton) 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
9.5 years
After this, it's pure profit
Upfront Cost
£8,139
What you pay to get started
Annual Benefit
£859
What you save every year
Profit Over 25 Years
£13,337
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 Southern, the current unit rate is 26.42p/kWh with a 49.70p/day standing charge. Your postcode’s south-facing sunshine yield is 1037 kWh/kW — 36 above the regional median (1001).

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 1037 kWh per year on a south-facing roof. We value self-used electricity at 26.4p and exported surplus at a baseline 10p via SEG. Use the calculator above for your exact tariff.

Unit rate
26.4p/kWh
Standing charge
49.7p/day
Sunshine yield (south)
1037 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: £859, Upfront: £8,139, Break-even: 9.5 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2074 kWh 830 kWh 1244 kWh £219 £124 £344 £3,256 9.5 yrs £3,617
3 kW 3111 kWh 1244 kWh 1867 kWh £329 £187 £515 £4,883 9.5 yrs £5,425
4 kW 4148 kWh 1659 kWh 2489 kWh £438 £249 £687 £6,511 9.5 yrs £7,234
5 kW 5185 kWh 2074 kWh 3111 kWh £548 £311 £859 £8,139 9.5 yrs £9,042
6 kW 6222 kWh 2489 kWh 3733 kWh £658 £373 £1,031 £9,767 9.5 yrs £10,850
7 kW 7259 kWh 2904 kWh 4355 kWh £767 £436 £1,203 £11,394 9.5 yrs £12,659
8 kW 8296 kWh 3318 kWh 4978 kWh £877 £498 £1,374 £13,022 9.5 yrs £14,467

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: £1,029, Upfront: £10,239, Break-even: 9.9 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2074 kWh 1244 kWh 830 kWh £329 £83 £412 £5,356 13.0 yrs £2,879
3 kW 3111 kWh 1867 kWh 1244 kWh £493 £124 £618 £6,983 11.3 yrs £5,368
4 kW 4148 kWh 2489 kWh 1659 kWh £658 £166 £823 £8,611 10.5 yrs £7,858
5 kW 5185 kWh 3111 kWh 2074 kWh £822 £207 £1,029 £10,239 9.9 yrs £10,347
6 kW 6222 kWh 3733 kWh 2489 kWh £986 £249 £1,235 £11,867 9.6 yrs £12,837
7 kW 7259 kWh 4355 kWh 2904 kWh £1,151 £290 £1,441 £13,494 9.4 yrs £15,326
8 kW 8296 kWh 4978 kWh 3318 kWh £1,315 £332 £1,647 £15,122 9.2 yrs £17,816

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: £1,114, Upfront: £11,639, Break-even: 10.4 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2074 kWh 1452 kWh 622 kWh £384 £62 £446 £6,756 15.2 yrs £2,160
3 kW 3111 kWh 2178 kWh 933 kWh £575 £93 £669 £8,383 12.5 yrs £4,990
4 kW 4148 kWh 2904 kWh 1244 kWh £767 £124 £892 £10,011 11.2 yrs £7,820
5 kW 5185 kWh 3629 kWh 1555 kWh £959 £156 £1,114 £11,639 10.4 yrs £10,650
6 kW 6222 kWh 4355 kWh 1867 kWh £1,151 £187 £1,337 £13,267 9.9 yrs £13,480
7 kW 7259 kWh 5081 kWh 2178 kWh £1,342 £218 £1,560 £14,894 9.5 yrs £16,310
8 kW 8296 kWh 5807 kWh 2489 kWh £1,534 £249 £1,783 £16,522 9.3 yrs £19,140

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: £1,140, Upfront: £13,389, Break-even: 11.7 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2074 kWh 1514 kWh 560 kWh £400 £56 £456 £8,506 18.7 yrs £614
3 kW 3111 kWh 2271 kWh 840 kWh £600 £84 £684 £10,133 14.8 yrs £3,547
4 kW 4148 kWh 3028 kWh 1120 kWh £800 £112 £912 £11,761 12.9 yrs £6,479
5 kW 5185 kWh 3785 kWh 1400 kWh £1,000 £140 £1,140 £13,389 11.7 yrs £9,411
6 kW 6222 kWh 4542 kWh 1680 kWh £1,200 £168 £1,368 £15,017 11.0 yrs £12,343
7 kW 7259 kWh 5299 kWh 1960 kWh £1,400 £196 £1,596 £16,644 10.4 yrs £15,275
8 kW 8296 kWh 6056 kWh 2240 kWh £1,600 £224 £1,824 £18,272 10.0 yrs £18,207

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: £1,157, Upfront: £15,139, Break-even: 13.1 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2074 kWh 1555 kWh 518 kWh £411 £52 £463 £10,256 22.2 yrs £-999
3 kW 3111 kWh 2333 kWh 778 kWh £616 £78 £694 £11,883 17.1 yrs £2,001
4 kW 4148 kWh 3111 kWh 1037 kWh £822 £104 £926 £13,511 14.6 yrs £5,001
5 kW 5185 kWh 3889 kWh 1296 kWh £1,027 £130 £1,157 £15,139 13.1 yrs £8,001
6 kW 6222 kWh 4666 kWh 1555 kWh £1,233 £156 £1,388 £16,767 12.1 yrs £11,002
7 kW 7259 kWh 5444 kWh 1815 kWh £1,438 £181 £1,620 £18,394 11.4 yrs £14,002
8 kW 8296 kWh 6222 kWh 2074 kWh £1,644 £207 £1,851 £20,022 10.8 yrs £17,002

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: £1,174, Upfront: £17,589, Break-even: 15.0 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2074 kWh 1597 kWh 477 kWh £422 £48 £470 £12,706 27.1 yrs £-3,313
3 kW 3111 kWh 2395 kWh 716 kWh £633 £72 £704 £14,333 20.3 yrs £-245
4 kW 4148 kWh 3194 kWh 954 kWh £844 £95 £939 £15,961 17.0 yrs £2,824
5 kW 5185 kWh 3992 kWh 1193 kWh £1,055 £119 £1,174 £17,589 15.0 yrs £5,892
6 kW 6222 kWh 4791 kWh 1431 kWh £1,266 £143 £1,409 £19,217 13.6 yrs £8,960
7 kW 7259 kWh 5589 kWh 1670 kWh £1,477 £167 £1,644 £20,844 12.7 yrs £12,029
8 kW 8296 kWh 6388 kWh 1908 kWh £1,688 £191 £1,878 £22,472 12.0 yrs £15,097

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 Southampton

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

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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.

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Insights for SO18

Figures below are tailored to SO18 — click through for full league tables.

Big-Roof Britain Rank #1946 of 2182
4.2 kWp (UK avg 5.1 kWp)
~9 panels (≈430 W)
Solar Payback Index Rank #313 of 2996
9.5 years (UK avg 10.8 years)
~£859 /yr • £8,139 upfront
Standing-Charge Drag Rank #729 of 2996
21.1% (UK avg 26.6%) drag on savings
£181 fixed • ~£859 /yr value
Aspect Penalty View ranking →
East −21.0% West −20.4%
Typical output loss versus a south-facing roof (lower is better)

Seasonal solar output in SO18

Monthly generation per kilowatt of solar panels

kWh 41 Jan 54 Feb 89 Mar 117 Apr 123 May 126 Jun 126 Jul 112 Aug 96 Sep 69 Oct 48 Nov 36 Dec
Best month Worst month Winter (Dec–Feb) Other months

Winter output: 50.7% of an average month (Dec–Feb)

Best / worst month: Jun / Dec

These figures show output per kilowatt (kW) of panels installed. In winter, a 1 kW system here produces about 44 kWh per month; the average month produces around 86 kWh. So a typical 4 kW home system would generate roughly 175 kWh in winter, or 346 kWh in an average month.

Your Area at a Glance

Your Electricity Rate
26.42p/kWh
Daily Fixed Charge
49.70p/day
Local Sunshine
1037kWh/kW
A 1 kW system generates ~1037 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: 47% • Flats: 38% • Bungalows: 7% Based on 9,512 properties

Coverage

Southampton (91%)|Eastleigh (9%)

Areas Covered

Bitterne Park, Harefield, West End South, Swaythling, Peartree, West End North, Bargate, Thornhill + 3 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 Southern

SO2 (Southampton)
≈0.3 km away
Local sunshine: ~1,031 kWh/kWp · -1% vs SO18
SO17 (Southampton)
≈1.9 km away
Local sunshine: ~1,031 kWh/kWp · -1% vs SO18
SO19 (Southampton)
≈2.0 km away
Local sunshine: ~1,063 kWh/kWp · +2% vs SO18
SO14 (Southampton)
≈2.5 km away
Local sunshine: ~1,037 kWh/kWp · -0% vs SO18
SO9 (Southampton)
≈2.7 km away
Local sunshine: ~1,050 kWh/kWp · +1% vs SO18
SO97 (Eastleigh)
≈3.2 km away
Local sunshine: ~1,038 kWh/kWp · +0% vs SO18

Similar sunshine across the UK

SS17 (Thurrock)
~1,037 kWh/kWp · -0% vs SO18
EX14 (East Devon)
~1,037 kWh/kWp · +0% vs SO18
EX2 (Exeter)
~1,038 kWh/kWp · +0% vs SO18